ABSTRACT
La telomerasa es la enzima responsable del mantenimiento de la longitud de los telómeros mediante la adición de secuencias repetitivas ricas en guanina, y su actividad se observa principalmente en gametos, células madre y células tumorales. En las células somáticas humanas el potencial de proliferación es limitado, alcanzando la senescencia luego de 50-70 divisiones celulares, debido a que la ADN polimerasa no es capaz de copiar el ADN en los extremos de los cromosomas. Por el contrario, en la mayoría de las células tumorales el potencial de replicación es ilimitado debido al mantenimiento de la longitud telomérica dado por la telomerasa. Los telómeros tienen proteínas adicionales que regulan la unión de la telomerasa. De la misma manera la telomerasa también se asocia con un complejo de proteínas que regulan su actividad. Este trabajo se centra en la estructura y función del complejo telómero/telomerasa y a cómo las alteraciones en su comportamiento conducen al desarrollo de diversas enfermedades, principalmente cáncer. El desarrollo de inhibidores del sistema telómero / telomerasa podría ser un blanco con posibilidades prometedoras.
Telomerase is the enzyme responsible for the maintenance of telomere length by adding guanine-rich repetitive sequences. Its activity can be seen in gametes, stem cells and tumor cells. In human somatic cells the proliferative potential is limited, reaching senescence after 50-70 cell divisions, because the DNA polymerase is not able to copy the DNA at the ends of chromosomes. By contrast, in most tumor cells the replicative potential is unlimited due to the maintenance of the telomeric length given by telomerase. Telomeres have additional proteins that regulate the binding of telomerase, likewise telomerase associates, with a protein complex that regulates its activity. This work focuses on the structure and function of the telomere/telomerase complex and how changes in its behavior lead to the development of different diseases, mainly cancer. Development of inhibitors of the telomere/telomerase complex could be a target with promising possibilities.
Subject(s)
Animals , Humans , Neoplasms/genetics , Telomerase/genetics , Telomere/physiology , Cellular Senescence/genetics , Cell Division/physiology , Neoplasms/enzymology , Telomerase/metabolism , Telomeric Repeat Binding Protein 1/physiology , /physiologyABSTRACT
Hypoxia-inducible factor-1 (HIF-1) is a critical nuclear transcriptional factor mediating cell adaptive response to hypoxia in mammalian and human .It is the key mediator which modulates oxygen homeostasis exclusively .In the one hand , HIF-1 can protect and promote kinds of physiological processes , such as embryo normal development , cartilage and bone formation .In the other hand, it is also involved in lots of human deceases which is caused by ischemia and hypoxia , such as tumor, diabetes and its complica-tions.The molecular mechanisms of HIF-1 involved in these diseases have become a research hotspot and such studies will provide the new therapeutic means for these diseases , recent new drug researches have been focused on HIF-1 related signal pathway inhibitors , HIF-1 activity inhibitors, HIF-1 targeted therapy, etc.
ABSTRACT
Aquaporins (AQP), abundant in diversity, are the member of the major intrinsic proteins (MIPs) family with extraordinary ability to transport water, and thus, play important roles in modulation of water relations in plants. The recent advances in classification, structural characteristics, and physiological functions during plant growth and development as well as the various regulation modes of the activity and the effects of several abiotic stresses (water stress and salt stress) and phytohormones (ABA, GA and ethylene) on the gene expression of AQP were reviewed.
ABSTRACT
Objective To construct pGL4.14-1uc eukaryotic expression vector for HLA-B27 promoter gene and explore the activity regulation of this promoter in Hela cells.Methods The HLA-B27 gene promot- er(-419 bp～1 bp)was amplified by polymerase chain reaction and was cloned into pGL4.14-luc vector to construct eukaryotic expression vector pGL4.14/B27 pro-luc.The purified pGL4.14/B27 pro-luc was stablely transfected into HeLa cells and the activity of HLA-B27 gene promoter was detected by luminometer.Results About 432 bp gene fragment was amplified by PCR from genomie DNA and pGL4.14/B27 pro-luc vector was constructed successfully.The activity of HLA-B27 promoter was 1.67?0.20,1.79?0.71,2.94?0.68,1.98?0.45 in Hela stable cells after treated with TNF-?,IFN-?,IFN-?and IFN-?for 48 hours.Conclusion TNF-?. IFN-?,IFN-?and IFN-?can regulate the B27 promoter activity.The high specific activity of constructed HLA-B27 promoter eukaryotic expression vector may be a good method for further research.