Downregulation of telomerase activity is cell mediated A Lack of in Biology Diagrams In addition, elements in chromosome 3 seem to be important in telomerase suppression. Introduction of chromosome 3 into telomerase-positive renal carcinoma cells 32 or breast carcinoma cells 33 resulted in the repression of hTERT expression, down-regulation of telomerase activity, up-regulation of telomerase shortening, and cessation of cell Thus, the study of telomerase activity regulation at the level of enzymatic complex activity seems to give an alternative. Anyway, it is still supposed to use both, activity and expression regulation methods, as adjuvant therapies similarly to G-quadruplex stabilization. Understanding of telomerase activity may then bring a new insight into
Negative regulation of telomerase activity can be achieved by sequestration of the enzyme in the nucleolus. Following DNA damage, hTERT transiently moves from the nucleoplasm to the nucleolus . This re-localization is hypothesized to reduce the probability of de novo telomere formation at sites of DNA damage . PinX1, an Telomerase is the enzyme responsible for maintenance of the length of telomeres by addition of guanine-rich repetitive sequences. Telomerase activity is exhibited in gametes and stem and tumor cells. In human somatic cells proliferation potential is strictly limited and senescence follows approximately 50-70 cell divisions. In this Review, we discuss the transcriptional regulation of human TERT, hTR processing, assembly of the telomerase complex, the cellular localization of telomerase and its recruitment to telomeres, and the regulation of telomerase activity. We also discuss the disease relevance of each of these steps of telomerase biogenesis.
Telomerase Regulation Biology Diagrams
Regulation of TERT transcription. Transcription from the TERT promoter is highly regulated and is the primary means of controlling telomerase levels in diverse cell types and cellular states. TERT
modulating telomerase activity as well [51]. Posttransla-tional regulation of telomerase activity can occur via reversible phosphorylation of TERT catalytic subunit at speci๏ฌc serine/threonine or tyrosine residues [51]. Due to multiple kinase and phosphatase activators and inhibitors the telomerase phosphorylation status may affect its Human telomerase activity regulation Mol Biol Rep. 2011 Jun;38(5):3339-49. doi: 10.1007/s11033-010-0439-x. Epub 2010 Nov 18. Authors This review summarizes the current state of knowledge of numerous telomerase regulation mechanisms that take place after telomerase subunits coding genes transcription. Thus we show the possible mechanisms of
