Browsing by Subject "Telomeres"

Now showing 1 - 3 of 3
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    Cytological and functional aspects of telornere maintenance
    (Murcia : F. Hernández, 1999) Dandjinou, A.T.; Dionne, I.; Gravel, S.; LeBel, C.; Parenteau, J.; Wellinger, R.J.
    The fact that eukaryotic chromosomes are linear poses a special problem for their maintenance: the natural ends of chromosomes must be distinguished from ends generated by chromosomal breakage and somehow, the chromosome ends must also be fully replicated to maintain their integrity. Telomeres, the complex structures at the ends of chromosomes are thought to be instrumental for both of these functions. However, recent insights in telomere biology suggest that these terminal structures do much more than just fulfil1 these two basic functions. Cytological data demonstrate that telomeres may play leading roles in chromatin organization and nuclear architecture during mitosis and meiosis. Moreover, non-functional telomeres may lead to genetic instability, a common prelude to cancer. Here, we review the basic functions of telomeres during chromosome replication and discuss the cytological aspects of telomere function during mitosis and meiosis.
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    Envejecimiento : un vistazo bajo la superficie.
    (Comunidad Autónoma de la Región de Murcia, Consejería de Educación y Cultura, Servicio de Publicaciones., 2024) Aparicio Sánchez, Marta
    Con el avance en las técnicas biomédicas se ha conseguido un aumento de la esperanza de la vida. No obstante, esto lleva consigo una serie de consecuencias y un impacto en el deterioro de nuestro organismo. Por ello, el modelo de pez cebra (Danio reiro) como modelo de investigación, no solo nos abre infinitas puertas para mejorar las condiciones de vida agravadas durante nuestra vejez, sino que también nos ayuda a entender de manera más comprensible las causas que lo provoca. Entre estas causas destaca una inactividad de una enzima presente en los extremos de las estructuras cromosómicas (telomerasa). Por ello, mediante la generación de líneas mutantes y transgénicas de Pez Cebra se pretende analizar su repercusión en el proceso de envejecimiento.
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    Telomerase activity in cancer as a diagnostic and therapeutic target
    (F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2000) Kyo, S.; Takakura, M.; Inoue, M.
    Major advances have been made in understanding the role of telomerase in cellular immortalization and carcinogenesis. Human telomeres undergo progressive shortening with cell division, and critical shortening of telomeres with cellular aging triggers a signal for cells to stop dividing and senesce. Telomerase is an enzyme that adds telomeric-repeated sequences to the ends of human chromosome DNA. Telomerase is active in the vast majority of tumors, but not in normal somatic tissues, and prevents progressive shortening of telomeres with cell division, probably giving tumor cells a growth advantage over normal cells. Highly-sensitive PCR-based TRAP (telomeric repeat amplification protocol) assay provided the means to analyze telomerase in a wide variety of tissues. Evidence has been accumulated that this assay may be useful as a potential diagnostic tool for cancer. The constituents of telomerase complex have recently been identified, and human telomerase reverse transcriptase (hTERT) has been found to be responsible for the enzymatic activity of telomerase. Detection of hTERT mRNA may therefore be useful for the screening and diagnosis of cancers. The mechanisms regulating hTERT expression have been extensively analyzed, and transcriptional regulation of hTERT has been found to be essential for hTERT expression, in which several nuclear factors including c-Myc play crucial roles. Understanding of such mechanisms might provide insight into molecular basis of human carcinogenesis and contributes to the development of novel cancer gene therapy targeting telomerase.