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
                had to do with the link between the length of the
chromosome tips,
                cancer, and aging. Telomeres shorten with aging and
                their length in cancer cells. The cellular mechanisms
that influence
                telomeres might be exploited by those seeking cancer
                and by those seeking to counter the effects of aging.
                experiments indicate that telomerase activity alone is
not sufficient
                for the immortalization of human keratinocytes or
                epithelial cells. Immortalization also requires the
inactivation of
                an enzyme designated Rb/p16INK4a.

                    Reference: Kiyono, T., Foster, S.A., Koop, J.I. et
                    1998. Both Rb/p16INK4a inactivation and telomerase
                    activity are required to immortalize human
                    cells. Nature 396(6706):84-88.

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