1. Interspecific studies of circadian genes period and timeless in Drosophila
- Author
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Faisal Nouroz, Mirko Pegoraro, Eran Tauber, Charalambos P. Kyriacou, and Shumaila Noreen
- Subjects
bp, base pair ,0301 basic medicine ,CRY, cryptochrome ,Time Factors ,Circadian clock ,DD, continuous dark ,CYC, cycle ,Timeless ,ns, not significant ,DD, constant darkness ,Animals, Genetically Modified ,DNA, deoxyribonucleic acid ,PCR, polymerase chain reaction ,Drosophila Proteins ,Phylogeny ,D. pseudoobscura ,Genetics ,biology ,Temperature ,Period Circadian Proteins ,General Medicine ,D. ps, D. pseudoobscura ,Circadian Rhythm ,CLOCK ,Drosophila melanogaster ,h, hour ,Period ,ZT, Zeitgeber time ,DAM, Drosophila activity monitoring ,Drosophila ,PAS, Per Ant Sim ,EP, evening peak ,Period (gene) ,L, litre ,LD, light dark cycle ,sec, second ,tim, timeless ,M, morning ,Motor Activity ,SEM, standard error of the mean ,Article ,03 medical and health sciences ,g, grams ,Species Specificity ,Animals ,Circadian rhythms ,CLOCK Proteins ,Circadian rhythm ,E, evening ,n.a., not available ,D., Drosophila ,min, minute ,Pers comm, personal communication ,Genetic Complementation Test ,fungi ,MP, morning peak ,biology.organism_classification ,CLK, clock ,030104 developmental biology ,D. mel, D. melanogaster ,Mutation ,RNA, ribonucleic acid ,TTFL, transcriptional translational feedback loop ,SD, standard deviation ,per, period ,Coevolution - Abstract
The level of rescue of clock function in genetically arrhythmic Drosophila melanogaster hosts using interspecific clock gene transformation was used to study the putative intermolecular coevolution between interacting clock proteins. Among them PER and TIM are the two important negative regulators of the circadian clock feedback loop. We transformed either the D. pseudoobscura per or tim transgenes into the corresponding arrhythmic D. melanogaster mutant (per01 or tim01) and observed >50% rhythmicity but the period of activity rhythm was either longer (D. pseudoobscura-per) or shorter than 24 h (D. pseudoobscura-tim) compared to controls. By introducing both transgenes simultaneously into double mutants, we observed that the period of the activity rhythm was rescued by the pair of hemizygous transgenes (~24 h). These flies also showed a more optimal level of temperature compensation for the period. Under LD 12:12 these flies have a D. pseudoobscura like activity profile with the absence of morning anticipation as well as a very prominent earlier evening peak of activity rhythm. These observation are consistent with the view that TIM and PER form a heterospecific coevolved module at least for the circadian period of activity rhythms. However the strength of rhythmicity was reduced by having both transgenes present, so while evidence for a coevolution between PER and TIM is observed for some characters it is not for others., Highlights • To understand the mechanism of intermolecular coevolution between period and its partner timeless, transgenes from D. pseudoobscura were introduced into D. melanogaster null mutants. • The single D. melanogaster transformants containing either per or tim from D. pseudoobscura displayed less than 50% rhythmicity and the period of locomotor activity rhythms was also either very long (26-31h for perps) or very short (21-22h for timps). • The two heterospecific transgenes together in the double mutant D. melanogaster flies could not show a significant increase in levels of rhythmicity however a significant improvement in the average period of locomotor activity was obtained (~24h). • Temperature compensation in the period of locomotor activity was also improved in these double tranformants. The Western blots and qPCR confirmed the expression of these transgenes.
- Published
- 2018