Researchers have determined that a gene present in mouse cells limits the number of times that a cell can divide. The gene is involved in a process, called senescence, which is thought to ensure that aging cells do not pass on harmful mutations. The researchers said the gene, known as SIRT1, suppresses longevity, and may play a role in regulating the aging process. But they caution against interpreting the results too broadly, because dividing mouse cells in culture are an imperfect model of how aging affects human cells.There is, however, some indication from the new studies that suppressing SIRT1 could prove important in techniques that researchers use to generate large numbers of normal cells for research. In this context, the SIRT1-deficient cells hold an advantage over other highly proliferative cell types, such as cancer cells, because although they divide indefinitely, they otherwise appear normal.The research team, led by Frederick W. Alt, a Howard Hughes Medical Institute investigator at Children’s Hospital, Boston, and Harvard Medical School, published its findings in the July 2005 issue of the journal Cell Metabolism. Katrin Chua and Raul Mostoslavsky in Alt’s laboratory were joint first authors of the article, which also included co-authors from the National Institutes of Health and Brigham and Women’s Hospital.
