Scientists Identify New Gene That Controls Sleep/...( i> and tim genes become active makin...)

i> and tim genes become active, making RNA--molecules essential to create the PER and TIM proteins--but only after sunset does the accumulated RNA prompt the cell to stockpile the PER and TIM proteins. At night, the proteins pair in the cytoplasm and then migrate into the nucleus, home to cells' genetic material. It is this movement to the nucleus that signals the per and tim genes to stop making RNA and, hence, new PER and TIM proteins. Near dawn, the old PER/TIM protein pairs disintegrate. With the proteins depleted, the per and tim genes begin to make RNA again by midday.

The pace of the clock is set by a time lag: while the per and tim genes are freed to make RNA early in the day, PER and TIM protein pairs form at night.

Previous work by Young's laboratory hinted that this delay was caused by the late arrival of one of the two protein partners, PER. Accumulation of PER is postponed because PER proteins are rapidly broken down in the cytoplasm when they are not paired with TIM. The new gene, double-time, regulates this process.

Young and co-workers named double-time after the way in which it affects the length of the fly's daily cycle. Both fruit flies and humans have activity rhythms that adapt perfectly to a 24-hour cycle of night and day, but the researchers identified three mutants of double-time that alter this cycle. The first produces an 18 hour clock, among the fastest of all other fruit fly clock mutants. The second mutation slows down the fly's clock, to about 28 hours. The third mutant blocks the circadian cycle altogether. The last mutant, which lacks the protein product of the double-time gene, provided the clues to deciphering the mechanism behind the circadian oscillations.

The researchers found that, in the mutants lacking double-time protein, very high levels of PER protein accumulate in the cytoplasm and these PER proteins no longer disintegrate when not paired with TIM, meaning that both PE
'"/>

Contact: Joseph Bonner or Paul Focazio
runews@rockvax.rockefeller.edu
212-327-7900
Rockefeller University
10-Jul-1998

Page: 1 2 3 4
Related biology news :

1. Scientists to prototype cyberinfrastructure for research and education access to ocean observatories
2. Scientists sequence genome of kind of organism central to biospheres carbon cycle
3. Scientists find nanowires capable of detecting individual viruses
4. Scientists discover potential new way to control drug-resistant bacteria
5. Scientists explore genome of methane-breathing microbe
6. Scientists decipher genetic code of biothreat pathogen
7. Stuck on you: Scientists lay bare secrets of bacterial attachment proteins
8. Scientists discover proteins involved in spread of HIV-1 infection
9. Scientists fear new Ebola outbreak may explain sudden gorilla disappearance
10. Scientists reinvent DNA as template to produce organic molecules
11. Scientists visualise cellular handmaiden that restores shape to proteins