X-Message-Number: 10708 Date: Fri, 06 Nov 1998 20:21:41 -0500 From: Jan Coetzee <> Subject: Immortality postponed Immortality postponed Not long ago, telomerase, the enzyme that builds up telomeres - the tips of chromosomes - was in the news. The media excitement had to do with the link between the length of the chromosome tips, cancer, and aging. Telomeres shorten with aging and maintain their length in cancer cells. The cellular mechanisms that influence telomeres might be exploited by those seeking cancer treatments and by those seeking to counter the effects of aging. New experiments indicate that telomerase activity alone is not sufficient for the immortalization of human keratinocytes or mammary epithelial cells. Immortalization also requires the inactivation of an enzyme designated Rb/p16INK4a. Reference: Kiyono, T., Foster, S.A., Koop, J.I. et al. 1998. Both Rb/p16INK4a inactivation and telomerase activity are required to immortalize human epithelial cells. Nature 396(6706):84-88. Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=10708