RESUMEN
Repetitive DNA regions are known as fragile chromosomal sites which present a high flexibility and low stability. Our focus was characterize fragile sites in 5S rDNA regions. The Ancistrus sp. species shows a diploid number of 50 and an indicative Robertsonian fusion at chromosomal pair 1. Two sequences of 5S rDNA were identified: 5S.1 rDNA and 5S.2 rDNA. The first sequence gathers the necessary structures to gene expression and shows a functional secondary structure prediction. Otherwise, the 5S.2 rDNA sequence does not contain the upstream sequences that are required to expression, furthermore its structure prediction reveals a nonfunctional ribosomal RNA. The chromosomal mapping revealed several 5S.1 and 5S.2 rDNA clusters. In addition, the 5S.2 rDNA clusters were found in acrocentric and metacentric chromosomes proximal regions. The pair 1 5S.2 rDNA cluster is co-located with interstitial telomeric sites (ITS). Our results indicate that its clusters are hotspots to chromosomal breaks. During the meiotic prophase bouquet arrangement, double strand breaks (DSBs) at proximal 5S.2 rDNA of acrocentric chromosomes could lead to homologous and non-homologous repair mechanisms as Robertsonian fusions. Still, ITS sites provides chromosomal instability, resulting in telomeric recombination via TRF2 shelterin protein and a series of breakage-fusion-bridge cycles. Our proposal is that 5S rDNA derived sequences, act as chromosomal fragile sites in association with some chromosomal rearrangements of Loricariidae.
Asunto(s)
Sitios Frágiles del Cromosoma , Fusión Génica/genética , ARN Ribosómico 5S/fisiología , Recombinación Genética/fisiología , Telómero/metabolismo , Animales , Inestabilidad Cromosómica , Diploidia , Evolución Molecular , Humanos , Hibridación Fluorescente in Situ , Conformación de Ácido Nucleico , Telómero/genéticaRESUMEN
Introducción: el continuo desarrollo molecular ha restado protagonismo a otras clasificaciones de la leucemia mieloide aguda (LMA) basadas en la morfología e histoquímica general. En el caso de la LMA existe un subtipo donde el gen AML1 (RUNX1), esencial para la normal hematopoyesis, se fusiona con el gen co-represor transcripcional ETO (RUNX1T1) generando una proteína anormal con múltiples efectos en la mielopoyesis.Objetivo:analizar el comportamiento del gen de fusión RUNX1-RUNX1T1.Métodos: se analizó el comportamiento de este gen de fusión en 174 pacientes con LMA, estudiados por reacción en cadena de la polimerasa con reverso transcripción (RT-PCR) en el laboratorio de Biología Molecular del Instituto de Hematología e Inmunología (IHI) entre enero del 2000 y agosto del 2013.Resultados: el 13,8 por ciento (24 pacientes) fue positivo al RUNX1-RUNX1T1. En dicho grupo la edad osciló entre los 3 y los 62 años, con una media de 20,9 años aunque la mayor incidencia fue en pacientes de edad pediátrica (1-19 años) con un 66,7 por ciento. Predominó el sexo masculino y el color de la piel no blanca con 62,5 por ciento y 58,3 por ciento respectivamente. De estos pacientes, el 37,5 por ciento presentaron un diagnóstico morfológico de M2, el 12,5 por ciento de M4 y la mitad de los casos 50 por ciento habían tenido un diagnóstico al debut, sugestivo de leucemia promielocítica (LPM); a este último grupo se le determinó la presencia del gen quimérico PML/RARα, para los que fueron negativos, demostrándose posteriormente el RUNX1-RUNX1T1. En un solo paciente se encontró la asociación de la duplicación interna en tándem (DIT) del FLT3 con el RUNK1-RUNX1T1...
Introduction: the molecular development has reduced importance to other classifications of acute myeloid leukemia (AML) based on morphology and general histochemistry. When AML1 (RUNX1) gene, essential for normal hematopoiesis, is fused to the transcriptional co-repressor ETO (RUNX1T1) gene, an abnormal protein with multiple effects on myelopoiesis is synthesized.Objective: analyze the behavior of the fusion gene RUNX1 - RUNX1T1 in our patients.Methods: this fusion gene was evaluated in 174 patients with AML studied by polymerase chain reaction with reverse transcription (RT - PCR) at the laboratory of Molecular Biology of the Institute of Hematology and Immunology (IHI), between January 2002 and August 2013.Results: twenty four patients (13,8 percent) were positive to RUNX1-RUNX1T1. In this group age ranged from 3 to 62 years with a mean of 20.9 years, although the incidence was higher in pediatric patients (1 - 19 years), 66,7 percent. Males and non-white individuals were predominant with 62,5 percent and 58,3 percent, respectively. Of these patients, 37,5 percent had a morphological diagnosis of AML M2; 12,5 percent of M4; and half of the patients (50 percent) had a diagnosis suggestive of promyelocytic leukemia (PML). In the latter group, the presence of the chimeric gene PML / RARα was determined; all these patients were negative for this fusion gene and later the RUNX1 - RUNX1T1 was demonstrated. The association of internal tandem duplication (ITD) - FLT3 with RUNK1 - RUNX1T1 was found in 8,3 percent.Conclusions: the fusion gene RUNX1 - RUNX1T1 in patients with morphological appearance of M3, once again confirms that molecular techniques are vital for the diagnosis of AML and morphology is relegated to cases where cytogenetic and molecular biology fails to define a genetic alteration(AU)
Asunto(s)
Humanos , Leucemia Mieloide Aguda/diagnóstico , Fusión Génica/genética , Proteínas Represoras , Leucemia Promielocítica Aguda/diagnósticoRESUMEN
Recurrent gene fusions between the genes TMPRSS2 and ERG have been described in prostate cancer (PCa) and are found in 27% to 79% of radical prostatectomy. This fusion transcription results in ERG overexpression, which can be detected by immunohistochemistry (IHC) and provide a potential diagnostic marker for PCa. Three tissue microarrays (TMAs) containing samples from 98 patients with PCa and one TMA of 27 samples from individuals without PCa were tested for ERG immunostaining, and the presence of TMPRSS2:ERG transcripts was confirmed by quantitative real time PCR (qRT-PCR). The results showed that 46.9% of tumors tested positive for ERG immunostaining, and this finding was consistent with the results of qRT-PCR testing (k = 0.694, p < 0.001). IHC had a specificity of 83.3% and a sensitivity of 81% in detecting TMPRSS2:ERG fusion. Patients with PSA < 4.0 ng/mL showed positive immunoreactivity for ERG (p = 0.031). Kaplan-Meier analysis suggested that ERG expression did not influence the time of biochemical recurrence. This study demonstrates that both IHC and qRT-PCR are useful tools in detecting TMPRSS2:ERG fusions. A correlation between ERG expression and clinical and pathological parameters was not found, but the frequency, specificity and recurrence of ERG in PCa suggests that it may be a potential adjunct diagnostic tool.
Asunto(s)
Fusión Génica/genética , Neoplasias de la Próstata/diagnóstico , Neoplasias de la Próstata/genética , Serina Endopeptidasas/genética , Transactivadores/genética , Biomarcadores de Tumor/genética , Brasil , Estudios de Casos y Controles , Humanos , Estimación de Kaplan-Meier , Masculino , Recurrencia Local de Neoplasia/genética , Sensibilidad y Especificidad , Transcripción Genética/genética , Regulador Transcripcional ERGRESUMEN
Ageneiosus is the most widely distributed genus of the family Auchenipteridae among South American river basins. Although chromosome studies in the family are scarce, this genus has the largest number of analyzed species, with 2n = 54 to 56 chromosomes, differing from the rest of the family (2n = 58). This study aimed to analyze Ageneiosus inermis from the Araguaia River basin. The diploid number found was of 56 chromosomes. Heterochromatin was allocated in terminal region of most chromosomes, plus a pericentromeric heterochromatic block in pair 1, a pair distinguished by size in relation to other chromosomes pairs. AgNORs were detected in only one submetacentric chromosome pair, which was confirmed by FISH. 5S rDNA was present in only one metacentric chromosome pair. Hybridization with [TTAGGG]n sequence marked the telomeres of all chromosomes, in addition to an ITS in the proximal region of the short arm of pair 1. The repetitive [GATA]n sequence was dispersed, with preferential location in terminal region of the chromosomes. Ageneiosus has a genomic organization somewhat different when compared to other Auchenipteridae species. Evidences indicate that a chromosomal fusion originated the first metacentric chromosome pair in A. inermis, rearrangement which may be a basal event for the genus.
Ageneiosus é o gênero da família Auchenipteridae mais amplamente distribuído em bacias da América do Sul. Apesar dos estudos cromossômicos nesta família serem escassos, este gênero tem o maior número de espécies analisadas, com número diploide variando de 54 a 56 cromossomos, o que difere do restante da família (2n = 58). Este estudo objetivou analisar Ageneiosus inermis da bacia do rio Araguaia. O número diploide encontrado foi de 56 cromossomos. A heterocromatina se mostrou localizada na região terminal da maioria dos cromossomos, além de um bloco heterocromático pericentromérico no par 1, um par facilmente distinguível no cariótipo pelo seu maior tamanho quando comparado aos outros pares do complemento. AgRONs foram detectadas em somente um par de cromossomos submetacêntricos, que foi confirmado pela FISH. 5S rDNA se mostrou presente em somente um par de cromossomos metacêntricos. A hibridização com a sequência [TTAGGG]n marcou os telômeros de todos os cromossomos, além de um ITS (sequência telomérica intersticial) na região proximal do braço curto do par 1. A sequência repetitiva [GATA]n se mostrou dispersa, com localização preferencial na região terminal dos cromossomos. Ageneiosus apresenta uma organização genômica um pouco diferente quando comparada a outras espécies de Auchenipteridae. As evidências indicam que uma fusão cromossômica originou o primeiro par de cromossomos metacêntricos de A. inermis, rearranjo que parece ser um evento basal para o gênero.
Asunto(s)
Animales , Fusión Génica/genética , Mapeo Cromosómico/veterinaria , Bagres/genética , Análisis Citogenético/veterinariaRESUMEN
Ageneiosus is the most widely distributed genus of the family Auchenipteridae among South American river basins. Although chromosome studies in the family are scarce, this genus has the largest number of analyzed species, with 2n = 54 to 56 chromosomes, differing from the rest of the family (2n = 58). This study aimed to analyze Ageneiosus inermis from the Araguaia River basin. The diploid number found was of 56 chromosomes. Heterochromatin was allocated in terminal region of most chromosomes, plus a pericentromeric heterochromatic block in pair 1, a pair distinguished by size in relation to other chromosomes pairs. AgNORs were detected in only one submetacentric chromosome pair, which was confirmed by FISH. 5S rDNA was present in only one metacentric chromosome pair. Hybridization with [TTAGGG]n sequence marked the telomeres of all chromosomes, in addition to an ITS in the proximal region of the short arm of pair 1. The repetitive [GATA]n sequence was dispersed, with preferential location in terminal region of the chromosomes. Ageneiosus has a genomic organization somewhat different when compared to other Auchenipteridae species. Evidences indicate that a chromosomal fusion originated the first metacentric chromosome pair in A. inermis, rearrangement which may be a basal event for the genus.(AU)
Ageneiosus é o gênero da família Auchenipteridae mais amplamente distribuído em bacias da América do Sul. Apesar dos estudos cromossômicos nesta família serem escassos, este gênero tem o maior número de espécies analisadas, com número diploide variando de 54 a 56 cromossomos, o que difere do restante da família (2n = 58). Este estudo objetivou analisar Ageneiosus inermis da bacia do rio Araguaia. O número diploide encontrado foi de 56 cromossomos. A heterocromatina se mostrou localizada na região terminal da maioria dos cromossomos, além de um bloco heterocromático pericentromérico no par 1, um par facilmente distinguível no cariótipo pelo seu maior tamanho quando comparado aos outros pares do complemento. AgRONs foram detectadas em somente um par de cromossomos submetacêntricos, que foi confirmado pela FISH. 5S rDNA se mostrou presente em somente um par de cromossomos metacêntricos. A hibridização com a sequência [TTAGGG]n marcou os telômeros de todos os cromossomos, além de um ITS (sequência telomérica intersticial) na região proximal do braço curto do par 1. A sequência repetitiva [GATA]n se mostrou dispersa, com localização preferencial na região terminal dos cromossomos. Ageneiosus apresenta uma organização genômica um pouco diferente quando comparada a outras espécies de Auchenipteridae. As evidências indicam que uma fusão cromossômica originou o primeiro par de cromossomos metacêntricos de A. inermis, rearranjo que parece ser um evento basal para o gênero.(AU)
Asunto(s)
Animales , Bagres/genética , Mapeo Cromosómico/veterinaria , Fusión Génica/genética , Análisis Citogenético/veterinariaRESUMEN
La leucemia mieloide crónica (LMC) es una neoplasia mieloproliferativa asociada a la presencia del gen de fusión BCR-ABL1 en la célula madre hematopoyética producto de la translocación t(9;22) 8q34;q11.2). Este nuevo gen codifica para una proteína tirosin quinasa con actividad oncogénica. Este estudio descriptivo de corte transverso tuvo como objetivo identificar y cuantificar los transcriptos BCR-ABL1 mediante técnicas de biología molecular en pacientes con sospecha clínica y en tratamiento de LMC, que concurrieron al laboratorio de Genética Molecular del Instituto de Investigaciones en Ciencias de la Salud desde tres hospitales públicos de referencia. Se estudiaron un total de 69 pacientes a partir de los cuales se obtuvieron 19 muestras antes del inicio del tratamiento y 57 a distintos tiempo durante el tratamiento con inhibidor de tirosin quinasa. Se analizó el tipo de transcripto en 42 muestras hallándose la isoforma b3a2 en el 64%, la b2a2 en el 31% y ambas en el 5%. A partir de las cuantificaciones realizadas en 57 muestras en tratamiento se determinó la respuesta molecular a los inhibidores de la tirosina quinsa. El 61% no alcanzó la RM Mayor y el 30% obtuvo una RM Mayor o Completa. Este estudio logró implementar por primera vez a nivel nacional la detección y cuantificación del transcripto BCR-ABL1 en pacientes con LMC, introduciéndose una herramientanecesaria para el diagnóstico y seguimiento de la respuesta al tratamiento.
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Fusión Génica/genética , Reacción en Cadena de la Polimerasa , Transcripción Reversa , Tesis Académicas como AsuntoRESUMEN
Breast carcinoma is the leading cause of cancer-related mortality in women worldwide, with an estimated 1.38 million new cases and 458,000 deaths in 2008 alone. This malignancy represents a heterogeneous group of tumours with characteristic molecular features, prognosis and responses to available therapy. Recurrent somatic alterations in breast cancer have been described, including mutations and copy number alterations, notably ERBB2 amplifications, the first successful therapy target defined by a genomic aberration. Previous DNA sequencing studies of breast cancer genomes have revealed additional candidate mutations and gene rearrangements. Here we report the whole-exome sequences of DNA from 103 human breast cancers of diverse subtypes from patients in Mexico and Vietnam compared to matched-normal DNA, together with whole-genome sequences of 22 breast cancer/normal pairs. Beyond confirming recurrent somatic mutations in PIK3CA, TP53, AKT1, GATA3 and MAP3K1, we discovered recurrent mutations in the CBFB transcription factor gene and deletions of its partner RUNX1. Furthermore, we have identified a recurrent MAGI3-AKT3 fusion enriched in triple-negative breast cancer lacking oestrogen and progesterone receptors and ERBB2 expression. The MAGI3-AKT3 fusion leads to constitutive activation of AKT kinase, which is abolished by treatment with an ATP-competitive AKT small-molecule inhibitor.
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Neoplasias de la Mama/clasificación , Neoplasias de la Mama/genética , Mutación/genética , Translocación Genética/genética , Algoritmos , Neoplasias de la Mama/patología , Subunidad alfa 2 del Factor de Unión al Sitio Principal/genética , Subunidad beta del Factor de Unión al Sitio Principal/genética , Análisis Mutacional de ADN , Exoma/genética , Femenino , Fusión Génica/genética , Humanos , Proteínas de la Membrana/genética , México , Proteínas Proto-Oncogénicas c-akt/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-akt/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , VietnamRESUMEN
We report the first quantitative and qualitative analysis of the poly (A)⺠transcriptome of two human mammary cell lines, differentially expressing (human epidermal growth factor receptor) an oncogene over-expressed in approximately 25% of human breast tumors. Full-length cDNA populations from the two cell lines were digested enzymatically, individually tagged according to a customized method for library construction, and simultaneously sequenced by the use of the Titanium 454-Roche-platform. Comprehensive bioinformatics analysis followed by experimental validation confirmed novel genes, splicing variants, single nucleotide polymorphisms, and gene fusions indicated by RNA-seq data from both samples. Moreover, comparative analysis showed enrichment in alternative events, especially in the exon usage category, in ERBB2 over-expressing cells, data indicating regulation of alternative splicing mediated by the oncogene. Alterations in expression levels of genes, such as LOX, ATP5L, GALNT3, and MME revealed by large-scale sequencing were confirmed between cell lines as well as in tumor specimens with different ERBB2 backgrounds. This approach was shown to be suitable for structural, quantitative, and qualitative assessment of complex transcriptomes and revealed new events mediated by ERBB2 overexpression, in addition to potential molecular targets for breast cancer that are driven by this oncogene.
Asunto(s)
Mama/citología , Mama/metabolismo , Perfilación de la Expresión Génica , Poli A/metabolismo , Receptor ErbB-2/metabolismo , Empalme Alternativo/genética , Secuencia de Bases , Línea Celular , Biología Computacional , Femenino , Fusión Génica/genética , Biblioteca de Genes , Genoma Humano/genética , Humanos , Polimorfismo de Nucleótido Simple/genética , Receptor ErbB-2/genética , Reproducibilidad de los ResultadosRESUMEN
Familial hyperaldosteronism type 1 is an autosomal dominant disorder attributed to a chimeric CYP11B1/CYP11B2 gene (CG). Its prevalence and manifestation in the pediatric population has not been established. We aimed to investigate the prevalence of familial hyperaldosteronism type 1 in Chilean hypertensive children and to describe their clinical and biochemical characteristics. We studied 130 untreated hypertensive children (4 to 16 years old). Blood samples for measuring plasma potassium, serum aldosterone, plasma renin activity, aldosterone/renin ratio, and DNA were collected. The detection of CG was performed using long-extension PCR. We found 4 (3.08%) of 130 children with CG who belonged to 4 unrelated families. The 4 patients with CG had very high aldosterone/renin ratio (49 to 242). In addition, we found 4 children and 5 adults who were affected among 21 first-degree relatives. Of the 8 affected children, 6 presented severe hypertension, 1 presented prehypertension, and 1 presented normotension. High serum aldosterone levels (>17.7 ng/dL) were detected in 6 of 8 subjects (range: 18.6 to 48.4 ng/dL) and suppressed plasma renin activity (≤0.5 ng/mL per hour) and high aldosterone/renin ratio (>10) in 8 of 8 children (range: 49 to 242). Hypokalemia was observed in only 1 of 8 children. We demonstrated that the prevalence of familial hyperaldosteronism type 1 in a pediatric hypertensive pediatric population was surprisingly high. We found a high variability in the clinical and biochemical characteristics of the affected patients, which suggests that familial hyperaldosteronism type 1 is a heterogeneous disease with a wide spectrum of presentations even within the same family group.
Asunto(s)
Presión Sanguínea/fisiología , Hiperaldosteronismo/genética , Hipertensión/fisiopatología , Adolescente , Adulto , Aldosterona/sangre , Niño , Preescolar , Chile/epidemiología , Comorbilidad , Estudios Transversales , Citocromo P-450 CYP11B2/genética , Salud de la Familia , Fusión Génica/genética , Humanos , Hiperaldosteronismo/epidemiología , Hiperaldosteronismo/patología , Hipertensión/sangre , Hipertensión/epidemiología , Reacción en Cadena de la Polimerasa , Potasio/sangre , Prevalencia , Renina/sangre , Esteroide 11-beta-Hidroxilasa/genéticaAsunto(s)
Presión Sanguínea/fisiología , Hiperaldosteronismo/genética , Hipertensión/fisiopatología , Aldosterona/sangre , Niño , Chile/epidemiología , Comorbilidad , Citocromo P-450 CYP11B2/genética , Salud de la Familia , Fusión Génica/genética , Humanos , Hiperaldosteronismo/epidemiología , Hiperaldosteronismo/patología , Hipertensión/sangre , Hipertensión/epidemiología , Potasio/sangre , Prevalencia , Renina/sangre , Esteroide 11-beta-Hidroxilasa/genéticaRESUMEN
Leptospirosis is a zoonotic infectious disease that affects both humans and animals. The existing genetic toolsfor Leptospira spp. have improved our understanding of the biology of this spirochete as well as the interaction ofpathogenic leptospires with the mammalian host. However, new tools are necessary to provide novel and useful information to the field. A series of promoter-probe vectors carrying a reporter gene encoding greenfluorescent protein (GFP) were constructed for use in L. biflexa. They were tested by constructing transcriptional fusions between the lipL41, Leptospiral Immunoglobulin-like A (ligA) and Sphingomielynase 2 (sph2) promoters from L. interrogansand the reporter gene. ligA and sph2 promoters were the most active, in comparison to the lipL41 promoter and the noninduced controls. The results obtained are in agreement with LigA expression from the L. interrogans Fiocruz L1-130 strain. The novel vectors facilitated the in vitro evaluation of L. interrogans promoter activity under defined growth conditions which simulate the mammalian host environment. The fluorescence and rt-PCR data obtained closely reflectedtranscriptional regulation of the promoters, thus demonstrating the suitability of these vectors for assessing promoter activity in L. biflexa.
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Animales , Fusión Génica/genética , Leptospira interrogans/genética , Leptospira interrogans/patogenicidad , Regiones Promotoras Genéticas/genéticaRESUMEN
Point mutations and small deletions and insertions in BRCA1 and BRCA2 genes are responsible of about 20% of hereditary breast cancer cases in Chilean population. Studies in other populations have identified the amplification and/or deletion of one or more exons in these genes as the cause of the disease. In this study the authors determined the presence of these types of alterations in BRCA1 and BRCA2, in 74 Chilean families with breast/ovarian cancer that were negative for germline mutations in these genes. Since these alterations are not detectable using the conventional PCR-based methods, the authors use MLPA (multiplex ligation-dependent probe amplification) to detect amplifications and/or deletions in BRCA1 and BRCA2 genes. The authors identified two different alterations in BRCA1: exon 10 duplication in one family and amplification of exons 3, 5, and 6 in two families. Duplication of exon 10 contains intronic adjacent sequences suggesting gene duplication. The second rearrangement consist of a 4 times amplification of a fragment containing exons 3, 5, and 6 joined together with no introns, suggesting the presence of a processed pseudogene. No alterations were detected in BRCA2. In order to validate the MLPA results and characterize the genomic alterations the authors performed qPCR, long range PCR, and sequencing.