The National Institute of Mental Health would like to call your attention to the first cloning of a gene that
codes for a biological clock responsible for daily rhythms in mammals. NIMH grantee Dr. Joseph
Takahashi and colleagues at Northwestern University report on their findings in the May 16 issue of Cell
(See Northwestern University press release at:
"The identification of a critical molecular switch controlling circadian rhythms in mammals is a major
scientific step," said NIMH Director Steven E. Hyman, M.D. "In addition to providing insights into normal
physiology, understanding biological clocks has important implications for human health. Biological clocks
are disturbed in problems ranging from the common, but trivial, such as jet lag, to devastating disorders,
such as manic depressive illness."
Takahashi and colleagues found expression of the mouse Clock gene not only in the brain and eyes, but
also in other tissue, suggesting a widespread role in timing-related regulation throughout the body. Similar
genetic material was also found in other vertebrates, including humans, suggesting that it has been conserved
Indeed, the Clock gene contains an amino acid sequence called the PAS domain that is present even in the
clock gene of a primitive single-cell organism, Neurospora, a type of bread mold, described by NIMH
grantee Dr. Jay Dunlap and colleagues at Dartmouth University in the May 2 issues of Cell and Science. All
biological clocks may thus share common molecular components, say the investigators.
For more information, call NIMH Office of Scientific Information (301) 443-4536.