RESUMEN

Natural products have been used in the treatment of illnesses throughout the history of humankind. Exploitation of bioactive compounds from natural sources can aid in the discovery of new drugs, provide the scaffold of new medicines. In the face of challenging diseases, such as the COVID-19 pandemic, for which there was no effective treatment, nature could offer insights as to novel therapeutic options for control measures. However, the environmental impact and supply chain of bioactive production must be carefully evaluated to ensure the detrimental effects will not outweigh the potential benefits gained. History has already proven that highly bioactive compounds can be rare and not suitable for medicinal exploitation; therefore, the sustainability must be accessed before expensive, time-demanding, and large trials can be initialized. A sustainable option to readily produce a phytotherapy with minimal environmental stress is the use of agro-industry wastes, a by-product produced in high quantities. In this review we evaluate the sustainability issues associated with the production of phytotherapy as a readily available tool for pandemic control.

RESUMEN

BACKGROUND: Muscles of individuals with Cerebral Palsy (CP) undergo structural changes over their lifespan including an increase in muscle stiffness, decreased strength and coordination. Being able to identify these changes non-invasively would be beneficial to improve understanding of CP and assess therapy effectiveness over time. This study aims to adapt an existing EMG-driven Hill-type muscle model for neuromuscular characterisation during isometric contractions of the elbow joint. METHODS: Participants with (n = 2) and without CP (n = 8) performed isometric force ramps with contraction levels ranging between 15 and 70% of their maximum torque. During these contractions, high-density EMG data were collected from the M. Biceps and Triceps brachii with 64 electrodes on each muscle. The EMG-driven Hill-type muscle model was used to predict torques around the elbow joint, and muscle characterisation was performed by applying a genetic algorithm that tuned individuals' parameters to reduce the RMS error between observed and predicted torque data. RESULTS: Observed torques could be predicted accurately with an overall mean error of 1.24Nm ± 0.53Nm when modelling individual force ramps. The first four parameters of the model could be identified relatively reliably across different experimental protocols with a full-scale variation of below 20%. CONCLUSION: An HD-EMG muscle modelling approach to evaluating neuromuscular properties in participants with and without CP has been presented. This pilot study confirms the feasibility of the experimental protocol and demonstrates some parameters can be identified robustly using the isometric contraction force ramps.

Asunto(s)

Parálisis Cerebral/fisiopatología , Contracción Isométrica/fisiología , Modelos Biológicos , Músculo Esquelético/fisiopatología , Adulto , Algoritmos , Articulación del Codo/fisiopatología , Electromiografía , Femenino , Humanos , Masculino , Dinamómetro de Fuerza Muscular , Procesamiento de Señales Asistido por Computador , Adulto Joven

RESUMEN

The Capsicum genus is one of the most popular plants consumed and cultivated worldwide, containing approximately 50 000 varieties of pepper. Due to its wide biodiversity, the chemical composition within the genus also presents a great variability. Its major applications are in food and pharmacological industry, as pepper presents a chemical composition rich in capsaicinoids, carotenoids, flavonoids and volatile compounds which is attributed to the ability of the fruit to remove insipidity, produce aromas and act against oxidative diseases. Due the existence of several cultivars there is a huge intraspecific chemical variability within each species, which can be considered as an obstacle when selecting and cultivating a species to be applied as a natural product source for a specific objective. The usage of pepper-based products in different industrial areas requires pre-established ranges of chemical compounds, such as capsaicinoids, which in high concentration are toxic when consumed by humans. Applying a pepper with a chemical profile closely related to the concentration that is required after industrial processing can improve efficacy and effectiveness of the process. An insight into the chemical characteristics of major secondary bioactive compounds within Capsicum, the factors that affect their concentration and their chemosystematic implication are reported and discussed.

RESUMEN

OBJECTIVE: Non-invasive neuromuscular characterization aims to provide greater insight into the effectiveness of existing and emerging rehabilitation therapies by quantifying neuromuscular characteristics relating to force production, muscle viscoelasticity and voluntary neural activation. In this paper, we propose a novel approach to evaluate neuromuscular characteristics, such as muscle fiber stiffness and viscosity, by combining robotic and HD-sEMG measurements with computational musculoskeletal modeling. This pilot study investigates the efficacy of this approach on a healthy population and provides new insight on potential limitations of conventional musculoskeletal models for this application. METHODS: Subject-specific neuromuscular characteristics of the biceps and triceps brachii were evaluated using robot-measured kinetics, kinematics and EMG activity as inputs to a musculoskeletal model. RESULTS: Repeatability experiments in five participants revealed large variability within each subjects evaluated characteristics, with almost all experiencing variation greater than 50% of full scale when repeating the same task. CONCLUSION: The use of robotics and HD-sEMG, in conjunction with musculoskeletal modeling, to quantify neuromuscular characteristics has been explored. Despite the ability to predict joint kinematics with relatively high accuracy, parameter characterization was inconsistent i.e. many parameter combinations gave rise to minimal kinematic error. SIGNIFICANCE: The proposed technique is a novel approach for in vivo neuromuscular characterization and is a step towards the realization of objective in-home robot-assisted rehabilitation. Importantly, the results have confirmed the technical (robot and HD-sEMG) feasibility while highlighting the need to develop new musculoskeletal models and optimization techniques capable of achieving consistent results across a range of dynamic tasks.

Asunto(s)

Dispositivo Exoesqueleto , Modelos Biológicos , Fuerza Muscular , Músculo Esquelético/fisiopatología , Rehabilitación/instrumentación , Adulto , Fenómenos Biomecánicos , Humanos , Masculino , Proyectos Piloto , Rehabilitación/métodos

RESUMEN

PURPOSE: Aim of the present study was to investigate the sensitivity of high resolution ultrasound (HRU), standard contrast-enhanced ultrasound (CEUS) and CEUS using a novel vascular endothelial growth factor receptor 2 (VEGFR2)-targeted contrast agent for the detection of hepatic metastases in a mouse model of colorectal cancer using clinical standard technology. MATERIALS AND METHODS: The human colon cancer cell line HT29, transfected with luciferase cDNA for in vivo bioluminescence monitoring, was injected intrasplenically into CB17.SCID mice. Mice were monitored weekly by bioluminescence and after 2 and 4.5 weeks by HRU and CEUS. Contrast media (untargeted BR1, targeted BR55) was applied and digital cine loops from the arterial phase (15 - 45 sec), portal venous phase (50 - 120 s) and late phases (3 - 5 min, 1hour) of the whole liver were analyzed. Data were correlated with postmortem histopathology. RESULTS: Without contrast enhancement, lesions > 4 mm were reliably detected. After use of untargeted CEUS, lesions > 2 mm were reliably detected and enhanced rim vascularization and late-phase wash-out was shown. With BR55, lesions > 0.8 mm were reliably detected with excellent documentation of vascularization. A persistent contrast enhancement was seen > 30 min after injection. Contrast-enhancement patterns with BR55 significantly correlated with CD31 (R2 = 0.74) and VEGFR2-immunohistochemistry (R2 = 0.66). CONCLUSION: Detection of metastases by HRU and CEUS was earlier and more accurate than monitoring via bioluminescence. In vivo monitoring of hepatic micrometastases can thus be performed without prior modification of cancer cells using standard technology.

Asunto(s)

Neoplasias del Colon/diagnóstico por imagen , Medios de Contraste , Aumento de la Imagen , Lipopéptidos/administración & dosificación , Neoplasias Hepáticas/diagnóstico por imagen , Neoplasias Hepáticas/secundario , Hígado/diagnóstico por imagen , Imagen Molecular , Ultrasonografía , Receptor 2 de Factores de Crecimiento Endotelial Vascular , Animales , Femenino , Células HT29 , Humanos , Mediciones Luminiscentes , Ratones , Ratones Endogámicos , Microburbujas , Trasplante de Neoplasias

RESUMEN

The oviposition behaviour of Gryon gallardoi (Hymenoptera; Scelionidae) on Spartocera dentiventris (Hemiptera; Coreidae) host eggs was investigated in the laboratory. Masses of 12 non-parasitized freshly laid (less than 24 h old) eggs were exposed to 2-5 days old mated females with previous oviposition experience (n = 10). Behaviour was observed for 2 h under the stereomicroscope. The eggs were Then kept individually at 25 degrees +/- 1 degree C/12 h photophase till hatching. The mean number of parasitized eggs was 7.8 +/- 0.81 (mean +/- SE). Five distinct kinds of behaviour were observed: drumming with antennae on the eggs, ovipositor insertion, egg marking, walking and resting. On average, ovipositor insertion was not followed by marking 4.3 +/- 0.76 times per female. In nearly all of these events, parasitism was unsuccessful. Walking and resting were observed less frequently than the other behaviours (1.6 +/- 0.56 and 2.1 +/- 0.48 times/female, respectively). Superparasitism occurred on average 3.6 +/- 0.88 times per egg mass, with 2.7 +/- 0.57 eggs being superparasitized. Among these, on average 87.4 +/- 5.37% led to successful development of an adult parasitoid. The average time spent on the each kind of oviposition behaviour was 1.5 +/- 0.57 min for drumming, 3.9 +/- 0.56 min for ovipositor insertion and 0.4 +/- 0.06 min for marking. There was no significant variation on the duration of each behaviour as the parasitoid progressed in parasitizing an egg mass. Ovipositor insertion almost always (87.58%) occurred in the longitudinal extremities of the egg. In average 31.1 +/- 7.21% of the individual emerging per egg mass were males, the larger proportion of males originating from the 2nd oviposition. The results show a range of oviposition behaviours common to the Scelionidae family. Egg marking behaviour was a good indicator of the effective oviposition by females. Superparasitism is only partially avoided, but its occurrence does not imply a failure of parasitoid emergence. The sex ratio is skewed towards females, and most males come from the first ovipositions.

Asunto(s)

Hemípteros/parasitología , Himenópteros/anatomía & histología , Oviposición/fisiología , Óvulo/parasitología , Animales , Conducta Animal , Femenino , Himenópteros/fisiología , Masculino

RESUMEN

The oviposition behaviour of Gryon gallardoi (Hymenoptera; Scelionidae) on Spartocera dentiventris (Hemiptera; Coreidae) host eggs was investigated in the laboratory. Masses of 12 non-parasitized freshly laid (less than 24 h old) eggs were exposed to 2-5 days old mated females with previous oviposition experience (n = 10). Behaviour was observed for 2 h under the stereomicroscope. The eggs were Then kept individually at 25 + or -1C/12 h photophase till hatching. The mean number of parasitized eggs was 7.8 + or - 0.81 (IMG01 + or - SE). Five distinct kinds of behaviour were observed: drumming with antennae on the eggs, ovipositor insertion, egg marking, walking and resting. On average, ovipositor insertion was not followed by marking 4.3 + or -imes per female. In nearly all of these events, parasitism was unsuccessful. Walking and resting were observed less frequently than the other behaviours (1.6 + or - 0.56 and 2.1 + or 0.48 times/female, respectively). Superparasitism occurred on average 3.6 + or - 0.88 times per egg mass, with 2.7 + or - 0.57 eggs being superparasitized. Among these, on average 87.4 + or - 5.37 percent led to successful development of an adult parasitoid. The average time spent on the each kind of oviposition behaviour was 1.5 + or - 0.57 min for drumming, 3.9 + or - 0.56 min for ovipositor insertion and 0.4 + or - 0.06 min for marking. There was no significant variation on the duration of each behaviour as the parasitoid progressed in parasitizing an egg mass. Ovipositor insertion almost always (87.58 percent) occurred in the longitudinal extremities of the egg. In average 31.1 + or - 7.21 percent of the individual emerging per egg mass were males, the larger proportion of males originating from the 2nd oviposition. The results show a range of oviposition behaviours common to the Scelionidae family. Egg marking behaviour was a good indicator of the effective oviposition by females. Superparasitism is only partially avoided, but its occurrence does not imply a failure of parasitoid emergence. The sex ratio is skewed towards females, and most males come from the first ovipositions

Asunto(s)

Animales , Femenino , Hemípteros , Himenópteros , Oviposición , Óvulo , Conducta Animal , Himenópteros

RESUMEN

The t(12;21)(p13;q22) chromosomal translocation is the most frequent illegitimate gene recombination in a pediatric cancer and occurs in approximately 25% of common acute lymphoblastic leukemia (cALL) cases. This rearrangement results in the in frame fusion of the 5'-region of the ETS-related gene, TEL (ETV6), to almost the entire acute myeloid leukemia 1 (AML1) (also called CBFA2 or PEBP2AB1) locus and expression of the TEL-AML1 chimeric protein. Although AML1 stimulates transcription, TEL-AML1 functions as a repressor of some AML1 target genes. In contrast to the wild type AML1 protein, both TEL and TEL-AML1 interact with N-CoR, a component of the nuclear receptor corepressor complex with histone deacetylase activity. The interaction between TEL and N-CoR requires the central region of TEL, which is retained in TEL-AML1, and TEL lacking this domain is impaired in transcriptional repression. Taken together, our results suggest that TEL-AML1 may contribute to leukemogenesis by recruiting N-CoR to AML1 target genes and thus imposing an altered pattern of their expression.

Asunto(s)

Proteínas de Unión al ADN/fisiología , Proteínas Nucleares/metabolismo , Proteínas de Fusión Oncogénica/fisiología , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Proteínas Proto-Oncogénicas , Proteínas Represoras/metabolismo , Factores de Transcripción/fisiología , Subunidad alfa 2 del Factor de Unión al Sitio Principal , Proteínas de Unión al ADN/genética , Expresión Génica , Humanos , Técnicas de Inmunoadsorción , Proteínas Nucleares/genética , Co-Represor 1 de Receptor Nuclear , Proteínas de Fusión Oncogénica/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Proteínas Proto-Oncogénicas c-ets , Proteínas Recombinantes , Proteínas Represoras/genética , Proteínas Represoras/fisiología , Factores de Transcripción/genética , Transfección , Proteína ETS de Variante de Translocación 6

RESUMEN

EEN, identified initially as a fusion partner to the mixed-lineage leukaemia gene in human leukaemia, and its related members, EEN-B1 and EEN-B2, have recently been shown to interact with two endocytic molecules, dynamin and synaptojanin, as well as with the huntingtin protein. In the present study, we show that the expression of the EEN gene-family members is differentially regulated. Multiple-spliced variants were identified for EEN-B2. In the brain, EEN-B1 and EEN-B2 mRNA are preferentially expressed in the cerebellar Purkinje and granule cells, dentate gyrus cells, hippocampal pyramidal neurons and cerebral granule cells. The expression patterns of EEN-B1 and EEN-B2 mRNA in the brain overlap with those of dynamin-I/III, synaptojanin-I and huntingtin, whereas the ubiquitous expression of EEN is consistent with that of dynamin-II. In testes, members of the EEN family are co-expressed with testis-type dynamin and huntingtin in Sertoli cells and germ cells respectively. Our results on the overlapping expression patterns are consistent with the proposed interaction of EEN family members with dynamin, synaptojanin and huntingtin protein in vivo. Although all three EEN family members bind to dynamin and synaptojanin, EEN-B1 has the highest affinity for binding, followed by EEN and EEN-B2. We also demonstrate that amphiphysin, a major synaptojanin-binding protein in brain, can compete with the EEN family for binding to synaptojanin and dynamin. We propose that recruitment of the EEN family by dynamin/synaptojanin to clathrin-coated pits can be regulated by amphiphysin.

Asunto(s)

Encéfalo/metabolismo , GTP Fosfohidrolasas/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Proteínas Nucleares/metabolismo , Monoéster Fosfórico Hidrolasas/metabolismo , Proteínas/genética , Proteínas/metabolismo , Empalme Alternativo , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Clonación Molecular , Dinamina I , Dinamina III , Dinaminas , Desarrollo Embrionario y Fetal , Inhibidores Enzimáticos/metabolismo , Regulación del Desarrollo de la Expresión Génica , Variación Genética , Humanos , Proteína Huntingtina , Enfermedad de Huntington/genética , Péptidos y Proteínas de Señalización Intracelular , Ratones , Datos de Secuencia Molecular , Familia de Multigenes , Neuronas/metabolismo , Unión Proteica , Proteínas Recombinantes de Fusión/metabolismo , Transcripción Genética

RESUMEN

Inappropriate activation of Abl family kinases plays a crucial role in different human leukaemias. In addition to the well known oncoproteins p190Bcr-Abl and p210Bcr-Abl, Tel-Abl, a novel fusion protein resulting from a different chromosomal translocation, has recently been described. In this study, the kinase specificities of the Bcr-Abl and Tel-Abl proteins were compared to the physiological Abl family kinases c-Abl and Arg (abl related gene). Using short peptides which correspond to the target epitopes in known substrate proteins of Abl family kinases, we found a higher catalytic promiscuity of Bcr-Abl and Tel-Abl. Similar to Bcr-Abl, Tel-Abl was found in complexes with the adapter protein CRKL. In addition, c-Crk II and CRKL are tyrosine phosphorylated and complexed with numerous other tyrosine phosphorylated proteins in Tel-Abl expressing Ba/F3 cells. GTPase analysis with a Ras-GTP-specific precipitation assay showed constitutive elevation of GTP-loaded Ras in cells expressing the leukaemic Abl proteins. The mitogenic MAPK/Erk kinases as well as Akt/PKB, a kinase implicated to negatively regulate apoptosis, were also constitutively activated by both Bcr-Abl and Tel-Abl. The results indicate that the leukaemic Abl-fusion proteins have catalytic specificities different from the normal kinases c-Abl and Arg and that Tel-Abl is capable to activate at least some pathways which are also upregulated by Bcr-Abl.

Asunto(s)

Proteínas Adaptadoras Transductoras de Señales , Sistema de Señalización de MAP Quinasas , Proteínas de Fusión Oncogénica/metabolismo , Fragmentos de Péptidos/metabolismo , Proteínas Serina-Treonina Quinasas , Células 3T3 , Secuencia de Aminoácidos , Animales , Catálisis , Línea Celular , Epítopos/metabolismo , GTP Fosfohidrolasas/metabolismo , Guanosina Trifosfato/fisiología , Células Madre Hematopoyéticas , Humanos , Sustancias Macromoleculares , Ratones , Datos de Secuencia Molecular , Proteínas Nucleares/metabolismo , Fragmentos de Péptidos/síntesis química , Fragmentos de Péptidos/química , Fosforilación , Procesamiento Proteico-Postraduccional , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Proto-Oncogénicas c-abl/metabolismo , Proteínas Proto-Oncogénicas c-akt , Proteínas Proto-Oncogénicas c-crk , Proteínas Proto-Oncogénicas p21(ras)/metabolismo , Especificidad por Sustrato , Translocación Genética

Asunto(s)

Genes Homeobox/genética , Proteínas de Homeodominio/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Mapeo Cromosómico , Clonación Molecular , Cruzamientos Genéticos , Ligamiento Genético , Marcadores Genéticos , Proteínas de Homeodominio/química , Hibridación Fluorescente in Situ , Hígado/metabolismo , Ratones , Ratones Endogámicos , Datos de Secuencia Molecular , Mapeo Restrictivo , Análisis de Secuencia , Factores de Transcripción

RESUMEN

Rearrangements of the MLL gene are associated with both myeloid and lymphoid acute leukaemia. The gene is commonly involved in reciprocal translocations leading to the creation of chimaeric genes encoding novel protein products. An alternative mechanism of MLL gene rearrangement is due to intragenic duplication, leading to partial duplication of the amino-terminal portion of the protein. This occurs in leukaemia, but it has recently been shown that partial duplications of the MLL gene are detectable in peripheral blood and bone marrow of healthy donors and in normal non-haemopoietic tissues. Sequence analysis of the 45 kb of the 5' end of the MLL locus encompassing the breakpoints of these genomic duplications has failed to show a definitive reason as to why this region is such a frequent target of rearrangement. Indeed, although the majority of the breakpoint joins are the result of apparent Alu-mediated homologous recombination, several joins do not involve Alu elements in the region, despite a high density of these repetitive elements in the sequence.

Asunto(s)

Cromosomas Humanos Par 11/genética , Duplicación de Gen , Proteínas de Fusión Oncogénica/genética , Secuencia de Bases , Humanos , Datos de Secuencia Molecular , Proteína de la Leucemia Mieloide-Linfoide , Análisis de Secuencia de ADN

Asunto(s)

Proteínas de Fusión Oncogénica/análisis , Médula Ósea/química , Médula Ósea/embriología , Enfermedades en Gemelos , Sangre Fetal/química , Humanos , Recién Nacido , Hígado/química , Hígado/embriología , Proteína de la Leucemia Mieloide-Linfoide , Proteínas de Fusión Oncogénica/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/sangre , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/patología , ARN Mensajero/sangre , Valores de Referencia , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa

RESUMEN

The Mixed Lineage Leukemia (MLL) gene is commonly involved in translocations in infantile leukemia and is amplified in some cases of adult myeloid leukemia. A homolog of MLL denoted MLL2, which represents the second human homolog of the Drosophila trithorax gene, was characterized by assembling ESTs, the KIAA0304 cDNA clone, RT - PCR fragments and a new clone isolated from a cDNA phage library and compared to the available genomic sequence. The MLL2 gene maps to 19q13.1, a region of frequent rearrangement or amplification in solid tumors. MLL2 consists of an 8.5 - 9 kb transcript and spans 20 kb of genomic DNA. The predicted MLL2 protein possesses all of the major domains defined in MLL and the two genes have a similar genomic structure. We find that MLL2 is amplified in two of 14 pancreatic carcinoma cell lines and one of five glioblastoma cell lines and is a likely critical gene in 19q13.1 amplifications. It is also a candidate for chromosomal rearrangements involving this chromosome locus. MLL2 is one additional mammalian trithorax-group gene with involvement in human cancer.

Asunto(s)

Cromosomas Humanos Par 19 , Proteínas de Unión al ADN/genética , Proteínas de Drosophila , Glioblastoma/genética , Neoplasias Pancreáticas/genética , Factores de Transcripción , Adulto , Secuencia de Aminoácidos , Animales , Mapeo Cromosómico , Proteínas de Unión al ADN/química , Drosophila/genética , Exones , Humanos , Hibridación Fluorescente in Situ , Intrones , Datos de Secuencia Molecular , Proteínas de Neoplasias/genética , Reacción en Cadena de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Alineación de Secuencia , Homología de Secuencia de Aminoácido , Transcripción Genética , Células Tumorales Cultivadas

RESUMEN

Rare, novel forms of activated ABL kinase, the result of a fusion between TEL (or ETV6, a member of the ETS transcription factor family), and the non-receptor tyrosine kinase ABL, have been identified. We have analysed the TEL/ABL fusion protein (type A) cloned from an acute lymphoblastic leukaemia patient. In contrast to a second TEL/ABL fusion (type B) identified in two cases of myeloid leukaemia, the portion of TEL contained in the type A TEL/ABL fusion was smaller and did not contain a potential Grb2 binding site. The type A TEL/ABL cDNA we used in this study encoded a 155 kD protein with elevated tyrosine kinase activity and was responsible for the phosphorylation of a number of proteins in vivo. Its expression in factor-dependent murine haemopoietic precursor cells efficiently converted these cells to factor independence for both survival and growth. These cells continued to express high levels of myc mRNA after growth factor depletion. We also demonstrated that type A TEL/ABL self-associated in stably expressing haemopoietic cells. Although the TEL portion of the TEL/ABL fusion protein has no sequence similarity to that of BCR in the BCR/ABL protein, all forms of these fusion proteins contain a structure implicated in oligomerization. Our results support the conclusion that the protein interaction domain of BCR and TEL, but not the Grb2 binding site, are the important functional components in the activation of ABL kinase in haemopoietic discase.

Asunto(s)

Transformación Celular Neoplásica , Proteínas de Unión al ADN/genética , Proteínas de Fusión bcr-abl/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Proteínas Tirosina Quinasas/genética , Proteínas Represoras , Factores de Transcripción/genética , Células Clonales , Hematopoyesis , Células Madre Hematopoyéticas/enzimología , Humanos , Fosforilación/efectos de los fármacos , Leucemia-Linfoma Linfoblástico de Células Precursoras/enzimología , Proteínas Tirosina Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-ets , Proteínas Proto-Oncogénicas c-myc/metabolismo , Proteína ETS de Variante de Translocación 6

RESUMEN

The MLL gene is interrupted and fused to a number of partner genes as a result of chromosomal translocations in human leukemias. MLL is a very large protein with a unique domain structure and large regions of homology to Drosophila trx. To define the key structural and functional domains of the MLL protein in vertebrates, we have cloned the genomic region encoding an MLL-like gene in the compact model vertebrate genome of Fugu rubripes. While the similarity between the mouse and human MLL proteins is very high, a lower overall similarity is present between the Fugu and mammalian proteins. Several new highly conserved regions were identified in the portion of the protein included in the MLL leukemia-associated fusion proteins. The conserved nature of regions of similarity between vertebrate forms of MLL and the Drosophila TRX proteins, as well as other domains previously suggested to have a functional role in MLL (including the AT hooks and the DNA methyltransferase domain), was also observed. Therefore, strong evolutionary constraints limited sequence divergence within these domains. The information derived from this comparative analysis will form the basis for the functional study of the MLL protein, particularly as it relates to human leukemogenesis.

Asunto(s)

Proteínas de Unión al ADN/genética , ADN/aislamiento & purificación , Proteínas de Drosophila , Drosophila/genética , Peces Venenosos/genética , Genes de Insecto , Genes/genética , Proto-Oncogenes , Factores de Transcripción , Secuencia de Aminoácidos , Animales , Secuencia Conservada/genética , ADN/química , ADN/genética , Evolución Molecular , Genoma , Datos de Secuencia Molecular , Proteína de la Leucemia Mieloide-Linfoide , Alineación de Secuencia , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido

RESUMEN

The MLL gene is frequently rearranged in acute human leukemia of both the myeloid and lymphoid lineages. Using a sensitive reverse transcriptase-polymerase chain reaction (RT-PCR) assay, we identified several abnormally spliced transcripts in which MLL exons were joined in an order different from the genomic orientation (scrambled exons). Mis-splicing of MLL was present in both normal and malignant tissues. Although the majority of these scrambled transcripts were joined accurately at consensus splice sites, there were several examples in which the junctions of exons spliced in aberrant order were at non-consensus sites. A number of features differentiate mis-splicing of MLL from the previously described cases of scrambled exons and circular RNAs. Some scrambled transcripts appear to be present in the polyadenylated fraction of RNA. No correlation of exon scrambling with exon skipping was found, and there was no particular tendency for the exons involved to be near large introns. Our data show that splicing of MLL is extremely complex. The presence of scrambled transcripts in both normal and leukemic cells, indistinguishable from transcripts resulting from genomic MLL rearrangements, precludes the use of nested RT-PCR as a screening method for detection of tandem duplication of tandem duplication of MLL.

Asunto(s)

Empalme Alternativo , Proteínas de Unión al ADN/biosíntesis , Proteínas de Unión al ADN/genética , Exones , Leucemia/genética , Familia de Multigenes , Proto-Oncogenes , Factores de Transcripción , Transcripción Genética , Enfermedad Aguda , Secuencia de Bases , Línea Celular , N-Metiltransferasa de Histona-Lisina , Humanos , Proteína de la Leucemia Mieloide-Linfoide , Reacción en Cadena de la Polimerasa , Sensibilidad y Especificidad , Células Tumorales Cultivadas , Dedos de Zinc

RESUMEN

The ETV6 (TEL) locus at chromosome band 12p 13 is a major site of translocations in acute leukemia, particularly in childhood acute lymphoblastic leukemia (ALL). In cases with translocations involving ETV6, the normal ETV6 allele is often deleted. In addition, loss of heterozygosity of ETV6 is frequently observed in childhood'ALL. Thus, it has been suggested that ETV6 may have an anti-oncogenic role to play, in addition to its oncogenic role. We have described an unusual case of ALL in which ETV6 is found fused to the ABL gene; ABL is normally activated by fusion to the BCR gene in the 9:22 translocation. We expanded the primary cells from this ETV6/ABL rearranged case of ALL in SCID animals and analyzed them for expression of both ETV6/ABL and the normal ETV6 mRNA. We found that both the rearranged and normal ETV6 mRNAs are expressed in the expanded cell population. Furthermore, sequence analysis of the ETV6 PCR product revealed no point mutations which would influence the amino acid sequence. Thus, deletion of the second ETV6 allele is not necessary for the transformation to leukemia by ETV6/ABL.

Asunto(s)

Alelos , Proteínas de Unión al ADN/genética , Genes abl/genética , Leucemia/genética , Proteínas Represoras , Proteínas Oncogénicas de Retroviridae/genética , Eliminación de Secuencia/genética , Factores de Transcripción/genética , Translocación Genética , Enfermedad Aguda , Humanos , Proteínas Proto-Oncogénicas c-ets , Proteína ETS de Variante de Translocación 6