How a circadian clock adapts to seasonal decreases in temperature and day length.
We show that a thermosensitive splicing event in the 3' untranslated region of the mRNA from the period (per) gene plays an important role in how a circadian clock in Drosophila adapts to seasonally cold days (low temperatures and short day lengths). The enhanced splicing of this intron at low temperatures advances the steady state phases of the per mRNA and protein cycles, events that significantly contribute to the preferential daytime activity of flies on cold days. Because the accumulation of PER is also dependent on the photosensitive TIMELESS (TIM) protein, long photoperiods partially counteract the cold-induced advances in the oscillatory mechanism by delaying the daily increases in the levels of TIM. Our findings also indicate that there is a temperature-dependent switch in the molecular logic governing cycles in per mRNA levels.
Majercak
J
J
Graduate Program in Biochemistry, Rutgers University, Piscataway, New Jersey 08854, USA.
Sidote
D
D
Hardin
P E
PE
Edery
I
I
D000222:Adaptation, Physiological; D017398:Alternative Splicing; D000818:Animals; D002940:Circadian Rhythm / Q000235:genetics*; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics*; D005786:Gene Expression Regulation; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism; D007438:Introns; D009043:Motor Activity; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D056950:Period Circadian Proteins; D017440:Photoperiod; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012621:Seasons; D013696:Temperature
D029721:Drosophila Proteins; D019476:Insect Proteins; D009687:Nuclear Proteins; C539040:PER protein, Drosophila; D056950:Period Circadian Proteins; D012333:RNA, Messenger; C096445:tim protein, Drosophila