CELLULAR CLOCK: From left, University of Texas Southwestern Medical Center at Dallas investigators Michel Ouellette, Woodring Wright, Jerry Shay, and Shawn Holt continue to investigate how telomerase regulates human cell division.
Comments by Jerry W. Shay and Woodring E. Wright, department of cell biology and neuroscience, University of Texas Southwestern Medical Center at Dallas
Telomeres--the ends of chromosomes--shorten during each round of cell replication, suggesting that they dictate the number of times a cell can divide before it reaches senescence. Almost all cancer cells and other immortalized cells thwart that stop mechanism by expressing telomerase, an enzyme that, in effect, rebuilds the chromosomal tips.
In an earlier Hot Paper feature (The Scientist, 10:14, May 27, 1996), Jerry W....