Natural variation in the splice site strength of a clock gene and species-specific thermal adaptation.
We show that multiple suboptimal splice sites underlie the thermal-sensitive splicing of the period (per) 3'-terminal intron (dmpi8) from D. melanogaster, enabling this species to prolong its midday "siesta," a mechanism that likely diminishes the deleterious effects of heat during the longer summer days in temperate climates. In D. yakuba and D. santomea, which have a more ancestral distribution indigenous to Afro-equatorial regions wherein day length and temperature exhibit little fluctuation throughout the year, the splicing efficiencies of their per 3'-terminal introns do not exhibit thermal calibration, consistent with the little effect of temperature on the daily distribution of activity in these species. We propose that the weak splice sites on dmpi8 underlie a mechanism that facilitated the acclimation of the widely colonized D. melanogaster (and possibly D. simulans) to temperate climates and that natural selection operating at the level of splicing signals plays an important role in the thermal adaptation of life forms.
Low
Kwang Huei
KH
Department of Molecular Biology and Biochemistry, Rutgers University, Center for Advanced Biotechnology and Medicine, Piscataway, NJ 08854, USA.
Lim
Cecilia
C
Ko
Hyuk Wan
HW
Edery
Isaac
I
D020413:3' Untranslated Regions / Q000235:genetics; D000222:Adaptation, Physiological / Q000235:genetics*; D000704:Analysis of Variance; D000818:Animals; D030801:Animals, Genetically Modified; D002461:Cell Line, Transformed; D002940:Circadian Rhythm / Q000235:genetics; D004330:Drosophila / Q000235:genetics / Q000502:physiology*; D029721:Drosophila Proteins / Q000235:genetics; D005786:Gene Expression Regulation / Q000235:genetics; D007438:Introns / Q000235:genetics; D008297:Male; D009043:Motor Activity / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics*; D056950:Period Circadian Proteins; D017440:Photoperiod; D022821:RNA Splice Sites / Q000235:genetics; D012326:RNA Splicing / Q000235:genetics*; D013045:Species Specificity; D013697:Thermosensing / Q000235:genetics*; D014162:Transfection
D020413:3' Untranslated Regions; D029721:Drosophila Proteins; D009687:Nuclear Proteins; C539040:PER protein, Drosophila; D056950:Period Circadian Proteins; D022821:RNA Splice Sites