부산대학교 도서관

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.yexcr.2008.05.007 Byline: Fay Minty (a)(b), Johanna K. Thurlow (a), Paul R. Harrison (a), E. Kenneth Parkinson (b) Keywords: Keratinocyte; Senescence; Telomere; TRF2; Microarray; DNA damage Abstract: The uncapping of telomeres has been shown to precipitate senescence in normal human fibroblasts and apoptosis in lymphocytes and p53-competent cancer cell lines. However, the effects of telomere uncapping on normal epithelial cells have not previously been examined. We have used the well characterised telomere repeat binding factor 2 (TRF2) dominant-negative mutant, TRF2.sup.[DELTA]B[DELTA]M, to deplete Normal Human Epidermal Keratinocytes (NHEK) telomeres of TRF2. We observed only a two fold increase in both phosphorylation of p53 at serine 15 and 53BP1 DNA damage foci and no detectable increase in p21.sup.WAF. Despite the weak DNA damage response, the keratinocytes growth arrest, demonstrate reduced colony formation and senescence. The small, abortive senescent colonies did not incorporate Brd-U within 48 h and expressed senescence-associated beta galactosidase (SA-[beta]-gal). Transcriptional profiling of TRF2-depleted keratinocytes showed a reproducible up-regulation of several genes. These included histones, genes associated with DNA damage and keratinocyte terminal differentiation. Several of the same genes were also shown to be up-regulated when keratinocytes undergo natural telomere-mediated senescence and down-regulated by ectopic telomerase expression. This study has thus revealed highly sensitive and specific candidate indicators of telomere dysfunction that may find use in identifying telomere-mediated keratinocyte senescence in ageing, cancer and other diseases. Author Affiliation: (a) Beatson Institute for Cancer Research Garscube Estate Switchback Road Bearsden, Glasgow G61 1BD, UK (b) Department of Clinical and Diagnostic Oral Sciences, Institute for Cell and Molecular Sciences, 4 Newark Street, London E1 2AT, UK Article History: Received 25 January 2008; Revised 24 April 2008; Accepted 13 May 2008