Dutch scientists' development of a mouse model with brittle, prematurely gray hair, described in the April 11 issue of Science, provides "strong evidence" for the developing theory that longevity depends on how well our genes can repair our own DNA. Two researchers at The University of Texas Health Science Center at San Antonio (UTHSC) make that comment in an invited editorial also in Science.
Jan Vijg, Ph.D., of the Health Science Center's Sam and Ann Barshop Center for Longevity and Aging Studies, and Paul Hasty, D.V.M., of UTHSC's Institute of Biotechnology, discussed research by Drs. Jan Hoeijmakers and Jan De Boer of Erasmus University in Rotterdam, The Netherlands. The Dutch scientists describe mice engineered with a defect in Xpd, a gene important for gene transcription (the translation of genetic material into proteins) and repair. The mice show deficits in both activities.
"This group engineered a small mutation that mimics a mutation found in humans," Dr. Hasty said. "The mutation causes trichothiodystrophy, a condition marked by brittle hair." In addition, the Dutch group observed that these mice prematurely exhibit signs of aging that include early graying, osteoporosis, infertility, muscle wasting and reduced life span. The group saw these symptoms earlier in the mutant mice than in the control mice. The mutant mice lived about a year, compared to two years for controls.
Most children with trichothiodystrophy die within five years of birth. Dr. Hasty has engineered a similar mouse mutating a different gene, Ku80, which is involved in repairing breakages in DNA. Deletion of Ku80 affects production of cells important to immune function. These mutant mice exhibit premature aging similar to that of the mice described by the Dutch group.
Dr. Vijg is collaborating with Drs. Hoeijmakers and De Boer in a joint research project. The results will be presented at an upcoming conference, "Functional Genomics of Aging," to be held April 24-27 in Seville, Spain. Dr. Vijg is a conference organizer and co-chair.
Dr. Vijg is director of the Human Genetics Program at the Barshop Center, professor in the UTHSC department of physiology and research health scientist with the South Texas Veterans Health Care System. Dr. Hasty is associate professor in the department of molecular medicine at the Health Science Center.
Note: Copies of the editorial and Dutch paper are available through the American Association for the Advancement of Science (AAAS) News & Information Office at (202) 326-6440.