Asunto(s)

Antígenos Transformadores de Poliomavirus/genética , Ratones Transgénicos/genética , Ratones Transgénicos/virología , Virus 40 de los Simios/genética , Animales , ADN Viral/administración & dosificación , ADN Viral/genética , ADN Viral/aislamiento & purificación , Modelos Animales de Enfermedad , Femenino , Genes Virales , Vectores Genéticos , Humanos , Masculino , Ratones , Ratones Transgénicos/inmunología , Microinyecciones , Oncogenes , Fenotipo , Virus 40 de los Simios/inmunología , Transformación Genética

RESUMEN

The Ets transcription factor family is involved in a variety of mammalian developmental processes at the cellular, tissue and organ levels. They are implicated in cellular proliferation, differentiation, migration, apoptosis and cell - cell interactions. This article reviews recent studies that demonstrate the integral importance of Ets in the dosage dependent regulation of development. The expression of many Ets genes is associated with mesenchymal - epithelial interactions and changes in extracellular matrix proteins. These inductive processes contribute to tissue remodeling and integrity, particularly during embryonic development. Overlapping as well as unique patterns of Ets expression are evident in developing tissues, including development of the lymphoid and myeloid lineages, brain and central nervous system, bone and mammary gland. Integration of these data will allow the development of predictive models for the regulation of complex developmental processes.

Asunto(s)

Desarrollo Embrionario y Fetal/genética , Regulación del Desarrollo de la Expresión Génica , Mamíferos/genética , Familia de Multigenes , Factores de Transcripción/fisiología , Animales , Mama/embriología , Mama/crecimiento & desarrollo , Diferenciación Celular/genética , División Celular/genética , Linaje de la Célula , Movimiento Celular/genética , Endotelio Vascular/citología , Endotelio Vascular/embriología , Células Epiteliales/citología , Femenino , Proteínas Fetales/genética , Proteínas Fetales/fisiología , Hematopoyesis/genética , Humanos , Leucemia/genética , Mamíferos/embriología , Glándulas Mamarias Animales/embriología , Glándulas Mamarias Animales/crecimiento & desarrollo , Mesodermo/citología , Ratones , Morfogénesis/genética , Sistema Musculoesquelético/embriología , Neovascularización Fisiológica/genética , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/fisiología , Oncogenes , Especificidad de Órganos , Proto-Oncogenes , Factores de Transcripción/genética

RESUMEN

Transgenic mice which express the simian virus 40 large T-antigen (Tag) under the regulatory control of the hormone responsive rat C3(1) gene develop unusual lesions of heterotopic bone growth associated with mixed tumor formation arising from eccrine sweat glands found only in the foot pads of mice, ischiocavernosus muscle adjacent to bulbourethral glands and occasionally the salivary and mammary glands. These lesions are very similar to mixed tumors arising in several types of human cancers. Based upon electron microscopic examination and immunocytochemical analyses of cellular differentiation markers, the mixed proliferative lesions in this transgenic mouse model begin with the Tag-induced proliferation of epithelial and myoepithelial cells. The proliferation of these two types of cells results in hyperplasia and adenomatous transformation of the epithelial component, whereas the proliferating myoepithelial cells undergo metaplasia to form chondrocytes which deposit extracellular matrix, including collagen fibers. Cartilage develops focally between areas of epithelial proliferation and subsequently ossifies through a process of endochondrial bone formation. The metaplasia of myoepithelial cells to chondrocytes appears to require the inductive interaction of factors produced by the closely associated proliferating epithelial cells, including members of the TGF-beta superfamily. We demonstrate that TGF-beta1 protein accumulates in the extracellular matrix of the lesions, whereas RNA in situ hybridization reveals that BMP-2, another strong inducer of heterotopic bone formation, is overexpressed by the proliferating epithelial cells during the development of ectopic bone. The formation of sarcomatous tumors within the mixed tumors appears to be androgen-dependent and more frequent in mice lacking a normal allele of p53. This process of cartilage and bone induction may mimic epithelial-mesenchymal interactions which occur during embryonic bone formation. These transgenic mice may provide new insights into the processes of ectopic endochondrial bone formation associated with mixed tumor formation and serve as a useful model for human heterotopic bone disease.

Asunto(s)

Proteínas Morfogenéticas Óseas/fisiología , Osificación Heterotópica/genética , Factor de Crecimiento Transformador beta/fisiología , Actinas/análisis , Proteína de Unión a Andrógenos/genética , Animales , Antígenos Virales de Tumores/análisis , Antígenos Virales de Tumores/genética , Proteína Morfogenética Ósea 2 , Proteínas Morfogenéticas Óseas/biosíntesis , Ectodisplasinas , Femenino , Enfermedades del Pie/etiología , Enfermedades del Pie/genética , Enfermedades del Pie/patología , Hormonas Esteroides Gonadales/fisiología , Inmunohistoquímica , Hibridación in Situ , Queratinas/análisis , Masculino , Proteínas de la Membrana/genética , Ratones , Ratones Transgénicos , Mutación , Neoplasias Complejas y Mixtas/genética , Neoplasias Complejas y Mixtas/fisiopatología , Neoplasias Complejas y Mixtas/ultraestructura , Osificación Heterotópica/patología , Osificación Heterotópica/fisiopatología , Proteínas de Unión a Fosfatidiletanolamina , Antígeno Nuclear de Célula en Proliferación/análisis , Prostateína , Secretoglobinas , Cloruro de Tolonio , Factor de Crecimiento Transformador beta/biosíntesis , Proteína p53 Supresora de Tumor/análisis , Proteína p53 Supresora de Tumor/fisiología , Uteroglobina , Vimentina/análisis

RESUMEN

We have generated a transgenic mouse model in which female mice develop ductal mammary adenocarcinomas and male mice develop prostatic adenocarcinomas by using a transgene containing the hormone-responsive rat prostatic steroid binding protein 5' flanking region C3(1) fused to the simian virus 40 (SV40) large T antigen. We have identified some genetic alterations during mammary and prostate tumor progression: (i) p53 is functionally inactivated during mammary cancer development without p53 mutations; (ii) Alterations in apoptosis during mammary tumor progression are p53 and bcl-2 independent; (iii) Ha-ras mutations occur early in the development of prostate cancer. This unique animal model offers the opportunity to study multistep tumorigenesis in these organs.

Asunto(s)

Adenocarcinoma/genética , Neoplasias de la Mama/genética , Neoplasias Mamarias Animales/genética , Neoplasias de la Próstata/genética , Animales , Apoptosis/genética , Modelos Animales de Enfermedad , Femenino , Genes bcl-2/genética , Genes p53/genética , Genes ras/genética , Masculino , Ratones , Ratones Transgénicos , Mutación , Fenotipo , Ratas

RESUMEN

BACKGROUND: Tumor vaccines show promise as a new approach for treating cancer. We have developed a murine prostate cancer cell line which can be used to study growth factor and extracellular matrix regulation of prostate differentiation and will be useful for generating tumor vaccines using the C3(1)/TAG transgenic model of prostate cancer. METHODS: Pr-14 cells were established in defined growth media (GM) and grown in GM, GM + 2% fetal bovine serum (FBS) or DMEM + 10% FBS on plastic, collagen, or Matrigel. Immunofluorescence and Western blot analyses were performed using antibodies to cytokeratin, vimentin, SV40 large T-antigen, and androgen receptor (AR). RESULTS: Pr-14 cells are cytokeratin-positive, vimentin-negative, and express SV40 large T-antigen. These cells are tumorigenic when injected into athymic nude mice and appear to be androgen-independent. Pr-14 cell lines are nontumorigenic when injected into syngeneic FVB/N mice, but form tumors in transgenic TAG-expressing FVB/N mice. Cell growth and morphology are dependent on media composition which determines whether ductal or acinar structures form when grown on Matrigel. CONCLUSIONS: The mouse prostate adenocarcinoma cell line, Pr-14, undergoes alterations in the state of differentiation dependent upon serum concentration when grown on Matrigel. The Pr-14 cell line is a useful reagent to study prostate cell/extracellular matrix interactions, and for immunotherapy and cancer vaccine studies in C3(1)/TAG transgenic mice.

Asunto(s)

Adenocarcinoma/patología , Neoplasias de la Próstata/patología , Células Tumorales Cultivadas , Células 3T3 , Adenocarcinoma/genética , Adenocarcinoma/metabolismo , Animales , Antígenos Transformadores de Poliomavirus/metabolismo , Western Blotting , División Celular/efectos de los fármacos , Colágeno/farmacología , Medios de Cultivo , Combinación de Medicamentos , Matriz Extracelular , Femenino , Técnica del Anticuerpo Fluorescente Indirecta , Antígenos H-2/biosíntesis , Cariotipificación , Laminina/farmacología , Masculino , Ratones , Ratones Desnudos , Ratones Transgénicos , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/metabolismo , Proteoglicanos/farmacología , Receptores Androgénicos/metabolismo , Coloración y Etiquetado

RESUMEN

Transgenic mice expressing the simian virus 40 large T-antigen (TAG) under the regulatory control of the rat prostatic steroid binding protein C3(1) gene develop mammary carcinomas (in females) and prostate carcinomas (in males). The development of carcinomas occurs several months after the appearance of dysplastic lesions, suggesting that TAG is necessary but insufficient for tumor formation and that other genetic events are involved in this process. TAG is known to bind to p53 and to result in its functional inactivation, which is believed to be a critical step in TAG-induced transformation. We investigated whether the TAG-p53 interaction is rate limiting in the development of phenotypic changes in these transgenic mice by crossing C3(1)/TAG transgenics with mice carrying null mutations of the p53 gene. TAG-expressing animals with a p53+/- genotype developed much more aggressive mammary tumors, as evidenced by increased numbers and size of metastases, than did TAG-expressing animals carrying two wild-type p53 alleles. While p53 was expressed in primary tumors, p53 expression appeared to be reduced or lost in many metastases in mice carrying either the p53+/+ or p53+/- genotypes. The tumorigenic process did not appear to be due to the loss of the second wild-type p53 allele or the gain of dominant oncogenic mutations in p53, as no mutations were detected in either primary or metastatic tumors by polymerase chain reaction--single-strand conformation polymorphism analyses. These findings suggest that despite the presence of TAG, p53 levels influence the characteristics of the late stages of mammary tumor growth and accelerate metastases. Functional loss of p53 and not p53 mutations participates in TAG-induced mammary carcinoma development and progression.

Asunto(s)

Adenocarcinoma/genética , Adenocarcinoma/patología , Genes p53 , Neoplasias Mamarias Experimentales/genética , Neoplasias Mamarias Experimentales/patología , Alelos , Animales , Antígenos Transformadores de Poliomavirus/biosíntesis , Antígenos Transformadores de Poliomavirus/genética , Northern Blotting , División Celular/fisiología , Femenino , Inmunohistoquímica , Masculino , Ratones , Ratones Transgénicos , Metástasis de la Neoplasia , Proteína p53 Supresora de Tumor/análisis , Proteína p53 Supresora de Tumor/biosíntesis , Proteína p53 Supresora de Tumor/fisiología

RESUMEN

Ets-1, a developmentally-regulated protooncogene, is expressed in multiple tissues during different stages of mouse development and cellular differentiation including high levels in lymphoid organs and endothelium. The putative roles of this DNA-binding protein in lymphoid development and maturation, as well as in angiogenesis and tumor vascularization, suggest that the regulation of Ets-1 may be critical to understanding these important developmental processes. We have cloned the mouse Ets-1 5' flanking region which shows significant homology to the human 5' flanking region, including potential transcription factor binding sites. Various amounts of mouse Ets-1 5' flanking, exon and intron sequences have been fused to the E. coli lacZ reporter gene and introduced into the mouse germline to identify genomic regions which regulate the developmental and tissue-specific expression of Ets-1. The 2.4 kb 5' flanking region of Ets-1 directs lacZ expression to the folding neural tube of embryos at gestational day 8.5 which is identical to the endogenous expression pattern of Ets-1. However, at later times in gestation, up to 5.3 kb of 5' flanking region results only in aberrant expression and is not able to confer lacZ expression in lymphoid or vascular tissues. When the first exon and 9 kb of the first intron are included with 5' flanking sequences, using an enhancer-trap-strategy, lacZ expression is observed in developing vessels, meninges and choroid plexus which correlates to endogenous Ets-1 expression. Further characterization of the vascular-specific element contained within intron I will provide important insights into the mechanisms controlling gene expression during angiogenesis.

Asunto(s)

Regulación del Desarrollo de la Expresión Génica , Intrones/fisiología , Ratones/embriología , Regiones Promotoras Genéticas/fisiología , Proteínas Proto-Oncogénicas/metabolismo , Factores de Transcripción/metabolismo , Animales , Genes Reporteros/genética , Operón Lac/genética , Ratones Endogámicos DBA , Ratones Transgénicos , Proteína Proto-Oncogénica c-ets-1 , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas c-ets , Análisis de Secuencia de ADN , Factores de Transcripción/genética , Transgenes/genética , beta-Galactosidasa/metabolismo

RESUMEN

Alterations in apoptosis and associated mechanisms during mammary tumor progression were investigated in transgenic mice expressing the SV40 large T antigen (T(AG)) driven by the rat prostatic steroid-binding protein C3(1) 5'-flanking region. Apoptosis levels, assessed by in situ end labeling, were low in normal mammary epithelial cells, highest in atypical hyperplasias (preneoplastic lesions), and less pronounced in adenocarcinomas. Preneoplastic cells maintain the ability to undergo apoptosis as a mechanism of tumor growth suppression, but this critical control of apoptosis is lost as these lesions progress to carcinomas. These alterations in apoptosis occur during mammary tumor progression in mice containing wild-type p53+/+ genotype as well as in mice with the p53-/- genotype. Thus, apoptosis in this tumor model occurs through a p53-independent mechanism. Because other studies have demonstrated p53-dependent apoptosis in T(AG)-induced choroid plexus tumors of transgenic mice, we propose that the role of p53 in apoptosis may be tissue-specific. In addition, bcl-2 protein was not expressed in any mammary lesions. SV40 T(AG) expression, which correlated with the nuclear p53 protein at all stages of tumor progression, was low in normal mammary epithelial cells, moderately high in atypical hyperplasias, and strongly expressed in adenocarcinomas. No p53 mutations were found at any stage of mammary adenocarcinoma development, suggesting that tumor progression does not require a dominantly acting p53 mutation in this transgenic model. p2l(Waf1/Cip1), a cyclin-dependent kinase inhibitor, was expressed in normal mammary tissue but was not detected in the mammary carcinomas, despite high nuclear accumulation of wild-type p53 protein, suggesting functional loss of p53 due to binding of SV40 T(AG), to p53. These findings suggest that suppression of apoptosis during the transition from atypical hyperplasia to adenocarcinoma appears to be a critical event for mammary cancer development in C3(1)/T(AG) transgenic mice and occurs by p53- and bcl-2-independent pathways.

Asunto(s)

Proteína de Unión a Andrógenos/fisiología , Antígenos Transformadores de Poliomavirus/fisiología , Apoptosis/fisiología , Transformación Celular Neoplásica/patología , Neoplasias Mamarias Experimentales/patología , Lesiones Precancerosas/patología , Proteína p53 Supresora de Tumor/fisiología , Proteína de Unión a Andrógenos/biosíntesis , Proteína de Unión a Andrógenos/genética , Animales , Antígenos Transformadores de Poliomavirus/biosíntesis , Antígenos Transformadores de Poliomavirus/genética , Secuencia de Bases , Western Blotting , Ciclo Celular , División Celular/fisiología , Inhibidor p21 de las Quinasas Dependientes de la Ciclina , Ciclinas/biosíntesis , Progresión de la Enfermedad , Femenino , Genes p53 , Genotipo , Neoplasias Mamarias Experimentales/metabolismo , Ratones , Ratones Transgénicos , Datos de Secuencia Molecular , Mutación , Reacción en Cadena de la Polimerasa , Polimorfismo Conformacional Retorcido-Simple , Lesiones Precancerosas/metabolismo , Antígeno Nuclear de Célula en Proliferación , Prostateína , Proteínas Proto-Oncogénicas/biosíntesis , Proteínas Proto-Oncogénicas c-bcl-2 , Ratas , Secretoglobinas , Proteína p53 Supresora de Tumor/biosíntesis , Proteína p53 Supresora de Tumor/genética , Uteroglobina

RESUMEN

Using differential display method, we have isolated and characterized a novel gene, N8, encoding an approximately 24 kDa protein. It is located on human chromosome 8q13 region. N8 gene is expressed at high levels in tumor derived cell lines from multiple cancers. It is also expressed at higher levels in lung tumors than normal lung tissue. N8 is also differentially expressed in fetal and adult tissues. In adult, N8 is expressed at high levels in brain, kidney, prostate, pancreas and intestine and at very low levels in lung, liver, hematopoietic cells and gonads. During murine embryonic development N8 is expressed in the epithelium of the intestine, stomach, olfactory epithelium, neuronal layers of retina, kidney and salivary gland. Taken together, these results suggest that N8 may play different roles during embryogenesis and in the adult animals.

Asunto(s)

Cromosomas Humanos Par 8 , Proteínas de Neoplasias/genética , Neoplasias/genética , Proteínas Represoras/genética , Secuencia de Aminoácidos , Secuencia de Bases , Northern Blotting , Línea Celular , Mapeo Cromosómico , Secuencia de Consenso , Cartilla de ADN , ADN Complementario , Femenino , Expresión Génica , Humanos , Hibridación in Situ , Cariotipificación , Leucina Zippers , Pulmón/metabolismo , Neoplasias Pulmonares/genética , Masculino , Datos de Secuencia Molecular , Neoplasias/patología , Especificidad de Órganos , Reacción en Cadena de la Polimerasa , ARN Mensajero/análisis , ARN Mensajero/biosíntesis , Homología de Secuencia de Aminoácido , Homología de Secuencia de Ácido Nucleico , Células Tumorales Cultivadas

RESUMEN

The protein product of the DRA gene, a gene whose expression is down-regulated in colon adenomas and adenocarcinomas, is a membrane glycoprotein and a member of a family of sulfate transporters. It is expressed in the intestinal tract (duodenum, ileum, cecum, distal colon), but not in the esophagus or stomach. DRA mRNA expression is restricted to the mucosal epithelium, and DRA protein expression is further limited to the columnar epithelial cells, particularly to the brush border. Consistent with its expression in the differentiated columnar epithelium of the adult human colon, DRA is first expressed in the midgut of developing mouse embryos at day 16.5, corresponding with the time of differentiation of the epithelium of the small intestine. A model for the structure of the DRA protein is proposed and its possible role in colon tumorigenesis is discussed.

Asunto(s)

Antiportadores , Proteínas Portadoras/genética , Intestinos/química , Glicoproteínas de Membrana/genética , Proteínas de la Membrana/genética , Animales , Células Cultivadas , Colon/metabolismo , Neoplasias del Colon/genética , ADN Complementario/análisis , Embrión de Mamíferos/metabolismo , Glicosilación , Ratones , ARN Mensajero/análisis , Transportadores de Sulfato

RESUMEN

Epidermal growth factor family members are widely expressed in human breast cancer and are thought to play an important dual role in mammary gland development and tumorigenesis. Overexpression of two relatively new members of this family, amphiregulin (AR) and Cripto-1 (CR-1), has been previously shown to transform immortalized human and mouse mammary epithelial cells. Here, we extend these results and address the disregulated expression of AR and CR-1 in many types of transgenic neoplastic mouse mammary tissues. Transgenic mouse strains overexpressing the oncogenes transforming growth factor-alpha, neu, int-3, polyoma virus middle T antigen, and simian virus 40 large T antigen have been previously shown to develop spontaneous mammary neoplasia. These models were each examined for mammary-tumor expression of AR and CR-1 by reverse transcription-polymerase chain reaction, western blot, and immunocytochemical analyses. Mammary tumors from each source expressed AR and CR-1. Western blot analysis revealed that, in all mammary tumors, AR and CR-1 protein species were processed differently than in virgin and lactating mouse mammary tissue. In addition, immunohistochemical detection of AR and CR-1 in tumor tissue revealed different patterns of growth-factor localization in different types of transgenic mouse mammary-derived tumors. These findings are consistent with the possibility of widespread roles for AR and CR-1 in the promotion and/or progression stages of mouse mammary tumorigenesis.

Asunto(s)

Biomarcadores de Tumor , Factor de Crecimiento Epidérmico , Glicoproteínas/metabolismo , Sustancias de Crecimiento/metabolismo , Péptidos y Proteínas de Señalización Intercelular , Neoplasias Mamarias Experimentales/genética , Glicoproteínas de Membrana , Proteínas de Neoplasias/metabolismo , Anfirregulina , Animales , Western Blotting , Familia de Proteínas EGF , Femenino , Proteínas Ligadas a GPI , Regulación Neoplásica de la Expresión Génica , Glicoproteínas/genética , Sustancias de Crecimiento/genética , Humanos , Técnicas para Inmunoenzimas , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Proteínas de Neoplasias/genética , ARN Mensajero/genética , ARN Neoplásico/genética

RESUMEN

We have examined the expression of three members of the ets family of genes, ETS1, ETS2 and ERGB/Fli-1, in lymphocytes from patients with systemic lupus erythematosus and in two murine autoimmune model systems. The ERGB/Fli-1 gene is expressed at a higher level in lymphocytes from autoimmune disease patients than healthy individuals. In addition, we found that the ERGB/Fli-1 gene expression is higher in splenic T-cells from lupus prone mice and in infiltrating lymphocytes in the salivary glands of HTLV-I tax transgenic mice. Taken together, these results suggest that the elevated expression of the ERGB/Fli-1 gene in lymphocytes may be a prelude to the development of autoimmune diseases.

RESUMEN

Transgenic mice that carry the HTLV-I Tax gene develop an exocrinopathy with some similarities to Sjoegren's syndrome. Our experiments reveal that these mice have lymphadenopathy and splenomegaly composed primarily of B lymphocytes, as well as abnormal levels of secreted immunoglobulins. To gain insight into whether the lymphadenopathy manifested by these transgenic mice was the result of induction of cytokines by Tax, we utilized cell lines from these mice to study in vitro B-cell responses. Conditioned media (CM) derived from the cell lines caused B-cells to proliferate when a second signal, surface Ig cross-linking, was provided. The CM also caused a marked enhancement of IgM secretion by spleen cells or by purified B-cells treated with supplemental cytokines. The B-cell proliferative response and enhanced IgM secretion have not been attributed to a known cytokine. These results suggest that the CM from the cell lines contain a factor(s) involved in novel pathways of B-cell growth and differentiation that may participate in the pathologic development of autoimmune disease.

Asunto(s)

Linfocitos B/inmunología , Productos del Gen tax/genética , Virus Linfotrópico T Tipo 1 Humano/genética , Animales , Linfocitos B/citología , División Celular , Medios de Cultivo Condicionados , Inmunoglobulina M/biosíntesis , Inmunoglobulina M/sangre , Ganglios Linfáticos/citología , Ratones , Ratones Transgénicos , Bazo/citología , Células Tumorales Cultivadas

RESUMEN

Tumor necrosis factor alpha (TNF-alpha) and soluble lymphotoxin (LT) (also called LT-alpha or TNF-beta) are cytokines with similar biological activities that are encoded by related and closely linked genes. TNF-alpha, a mediator of the inflammatory response, exists in soluble and transmembrane forms. LT-alpha can be secreted or retained at the cell surface by binding to a 33-kDa transmembrane subunit, LT-beta. The recently cloned human LT-beta gene encodes another TNF family member and is linked to the TNF/LT locus within the major histocompatibility complex locus. The cell surface LT is a heterotrimer consisting of LT-alpha and LT-beta, whose physiological function is not yet clearly defined. We now report the sequence analysis of the genomic region and cDNA of murine LT-beta gene, which is closely associated with the TNF-alpha and LT-alpha genes within the murine major histocompatibility complex locus. Unlike the TNF-alpha, LT-alpha, and human LT-beta genes, which contain four exons, the murine LT-beta contains three exons and encodes a 244-amino acid polypeptide with a 66-amino acid insert that is absent from the human homologue. In situ hybridization demonstrates constitutive expression of LT-beta in lymphoid and hematopoietic tissues. LT-beta transcription is maximal in the thymic medulla and in splenic white pulp. LT-beta mRNA is also detected in the skin and in specific regions of the brain. The LT-beta promoter region contains putative Ets-binding sites, suggesting that the expression of LT-beta may be regulated in part by Ets transcription factors whose pattern of lymphoid expression overlaps that of LT-beta.

Asunto(s)

Clonación Molecular , Regulación del Desarrollo de la Expresión Génica , Linfotoxina-alfa/genética , Complejo Mayor de Histocompatibilidad/genética , Proteínas de la Membrana/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , ADN Complementario/genética , Exones/genética , Humanos , Linfotoxina-alfa/biosíntesis , Linfotoxina beta , Proteínas de la Membrana/biosíntesis , Ratones , Datos de Secuencia Molecular , Especificidad de Órganos , Empalme del ARN , ARN Mensajero/biosíntesis , ARN Mensajero/metabolismo , Mapeo Restrictivo , Análisis de Secuencia de ADN , Factor de Necrosis Tumoral alfa/genética

RESUMEN

A transgenic mouse model for prostate and mammary cancer has been developed in mice containing a recombinant gene expressing the simian virus 40 early-region transforming sequences under the regulatory control of the rat prostatic steroid binding protein [C3(1)] gene. Male transgenic mice develop prostatic hyperplasia in early life that progresses to adenoma or adenocarcinoma in most animals surviving to longer than 7 months of age. Prostate cancer metastases to lung have been observed. Female animals from the same founder lines generally develop mammary hyperplasia by 3 months of age with subsequent development of mammary adenocarcinoma by 6 months of age in 100% of the animals. The development of tumors correlates with the expression of the transgene as determined by Northern blot and immunohistochemical analyses. The results of these experiments demonstrate that the C3(1) regulatory region used in these experiments is useful for targeting expression to the prostate and mammary gland. To our knowledge, this experimental system is the first reported transgenic mouse model for prostate cancer. These transgenic animals offer the opportunity to study hormone response elements in vivo and the multistage progression from normal tissue to carcinoma in the prostate and mammary glands.

Asunto(s)

Adenocarcinoma/genética , Proteína de Unión a Andrógenos/genética , Antígenos Transformadores de Poliomavirus/genética , Neoplasias Mamarias Experimentales/genética , Neoplasias de la Próstata/genética , Animales , Secuencia de Bases , Cartilla de ADN/química , Modelos Animales de Enfermedad , Femenino , Regulación Neoplásica de la Expresión Génica , Masculino , Neoplasias Mamarias Experimentales/patología , Ratones , Ratones Transgénicos , Datos de Secuencia Molecular , Regiones Promotoras Genéticas , Prostateína , Neoplasias de la Próstata/patología , Proteínas Recombinantes de Fusión , Secretoglobinas , Distribución Tisular , Uteroglobina

RESUMEN

ets-1 and ets-2 genes have previously been identified by their sequence homology to the v-ets oncogene of the avian erythroblastosis virus, E26. These cellular genes have been shown to function as transcription factors important in lymphoid differentiation and activation and cellular proliferation. In this study, we have broadly analysed the differential expression of ets-1 and ets-2 during murine development using in situ hybridization. Our results indicate that these transcription factors are expressed in multiple tissues during critical stages of embryo formation and organogenesis, suggesting that these genes may serve multiple functions during mouse development. The patterns of expression of both genes are quite different as early as day 8.0 of gestation. ets-1 expression is clearly observed during a narrow developmental stage in the developing nervous system, including the presumptive hindbrain regions, the neural tube, as well as neural crest and the first and second branchial arches, ets-2 expression is limited to the developing limb buds and distal tail. At later times, ets-1 expression is observed in developing vascular structures, including the heart, arteries, capillaries and meninges, whereas ets-2 is highly expressed in developing bone, tooth buds, epithelial layers of the gut, nasal sinus and uterus, and several regions of the developing brain. Both ets-1 and ets-2 are expressed in developing lung, gut and skin. High levels of expression in both genes is observed in adult lymphoid tissues, but in different tissue subsets. ets-1 is expressed in the adult lung, gut mesenchyme and bone marrow. ets-2 continues to be expressed at low levels in several adult tissues, except in the differentiated brain, where substantial levels of expression are found in particular regions of the mature brain. These results demonstrate that ets-1 and ets-2 are differentially regulated, are widely expressed in many tissues during murine embryogenesis and may play important roles in cellular proliferation and differentiation during mouse development.

Asunto(s)

Proteínas de Unión al ADN , Desarrollo Embrionario y Fetal , Regulación de la Expresión Génica , Proteínas Proto-Oncogénicas/genética , Proto-Oncogenes , Proteínas Represoras , Transactivadores , Factores de Transcripción , Animales , Femenino , Ratones , Proteína Proto-Oncogénica c-ets-1 , Proteína Proto-Oncogénica c-ets-2 , Proteínas Proto-Oncogénicas c-ets

RESUMEN

Glucocorticoid actions in the brain, particularly in the hippocampus and the hypothalamus, are critically involved in the response of the organism to stress. The key molecules in this process are the corticosteroid receptors, which upon activation, migrate and act in the nucleus. We have investigated the effect of stress on the activated form of the cytosolic glucocorticoid receptor from the above brain areas, using anion exchange chromatography. Exposure of rats to chronic stress resulted in the disappearance of the chromatographic peak, which corresponds to the activated form (DE II) of the hormone-receptor complex. For this phenomenon to occur, 1) the animal must be exposed to chronic, and not to acute stress, and 2) the adrenals of the animal must be intact. The disappearance of the activated form of the hormone-receptor complex (DE II) following chronic stress is most probably due to proteolysis of the receptor molecule, since it is specifically inhibited by the protease inhibitor leupeptin. This phenomenon may represent an adaptive mechanism which helps the organism cope with a repeated stressor.

RESUMEN

Glutamic acid decarboxylase (GAD) enzyme activity was measured in synaptosomes prepared from the hypothalamus, the hippocampus, the striatum and the cerebral cortex of control, adrenalectomized and rats exposed to a thermal stress. Adrenalectomy caused a statistically significant decrease in the enzyme activity in the striatum, while it had no effect in the other three brain areas. On the other hand, exposure to the thermal stress resulted in a dramatic increase of GAD specific activity in all brain areas examined. This thermal stress-induced increase in enzyme activity was observed in both non-operated and adrenalectomized animals, which implies that it is not mediated by glucocorticoids.

Asunto(s)

Adrenalectomía , Encéfalo/enzimología , Glutamato Descarboxilasa/metabolismo , Calor , Estrés Fisiológico/enzimología , Animales , Corteza Cerebral/enzimología , Cuerpo Estriado/enzimología , Hipocampo/enzimología , Hipotálamo/enzimología , Masculino , Ratas , Ratas Endogámicas , Estrés Fisiológico/etiología , Sinaptosomas/enzimología

RESUMEN

Previous studies have shown that turkey erythrocyte lamin B is anchored to the nuclear envelope via a 58-kD integral membrane protein termed p58 or lamin B receptor (Worman H. J., J. Yuan, G. Blobel, and S. D. Georgatos. 1988. Proc. Natl. Acad. Sci. USA. 85:8531-8534). We now identify a p58 analogue in the yeast Saccharomyces cerevisiae. Turkey erythrocyte lamin B binds to yeast urea-extracted nuclear envelopes with high affinity, associating predominantly with a 58-kD polypeptide. This yeast polypeptide is recognized by polyclonal antibodies against turkey p58, partitions entirely with the nuclear fraction, remains membrane bound after urea extraction of the nuclear envelopes, and is structurally similar to turkey p58 by peptide mapping criteria. Using polyclonal antibodies against turkey erythrocyte lamins A and B, we also identify two yeast lamin forms. The yeast lamin B analogue has a molecular mass of 66 kD and is structurally related to erythrocyte lamin B. Moreover, the yeast lamin B analogue partitions exclusively with the nuclear envelope fraction, is quantitatively removed from the envelopes by urea extraction, and binds to turkey lamin A and vimentin. As many higher eukaryotic lamin B forms, the yeast analogue is chemically heterogeneous comprising two serologically related species with different charge characteristics. Antibodies against turkey lamin A detect a 74-kD yeast protein, slightly larger than the turkey lamin A. It is more abundant than the yeast lamin B analogue and partitions between a soluble cytoplasmic fraction and a nuclear envelope fraction. The yeast lamin A analogue can be extracted from the nuclear envelope by urea, shows structural similarity to turkey and rat lamin A, and binds to isolated turkey lamin B. These data indicate that analogues of typical nuclear lamina components (lamins A and B, as well as lamin B receptor) are present in yeast and behave as their vertebrate counterparts.

Asunto(s)

Núcleo Celular/ultraestructura , Membrana Nuclear/metabolismo , Proteínas Nucleares/inmunología , Receptores de Superficie Celular/inmunología , Saccharomyces cerevisiae/fisiología , Animales , Fraccionamiento Celular , Citoplasma/inmunología , Immunoblotting , Lamina Tipo A , Lamina Tipo B , Laminas , Peso Molecular , Membrana Nuclear/inmunología , Proteínas Nucleares/metabolismo , Receptores de Superficie Celular/metabolismo , Especificidad de la Especie , Pavos