title: period and timeless mRNA Splicing Profiles under Natural Conditions in Drosophila melanogaster.
abstract: Previous analysis of Drosophila circadian behavior under natural conditions has revealed a number of novel and unexpected features. Here we focus on the oscillations of per and tim mRNAs and their posttranscriptional regulation and observe significant differences in molecular cycling under laboratory and natural conditions. In particular, robust per mRNA cycling from fly heads is limited to the summers, whereas tim RNA cycling is observed throughout the year. When both transcripts do cycle, their phases are similar, except for the very warmest summer months. We also study the natural splicing profiles of per and tim transcripts and observe a clear relationship between temperature and splicing. In natural conditions, we confirm the relationship between accumulation of the per(spliced) variant, low temperature, and the onset of the evening component of locomotor activity, first described in laboratory conditions. Intriguingly, in the case of tim splicing, we detect the opposite relationship, with tim(spliced) expression increasing at higher temperatures. A first characterization of the 4 different TIM protein isoforms (resulting from the combination of the natural N-terminus length polymorphism and the C-terminus alternative splicing) using the 2-hybrid assay showed that the TIM(unspliced) isoforms have a stronger affinity for CRY, but not for PER, suggesting that the tim 3' splicing could have physiological significance, possibly in temperature entrainment and/or adaptation to seasonal environments.
authors.affiliation: Department of Biology, University of Padova, Padova, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Montelli
authors.affiliation: Department of Biology, University of Padova, Padova, Italy.
authors.forename: Gabriella
authors.initials: G
authors.lastname: Mazzotta
authors.affiliation: Department of Biology, University of Padova, Padova, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Vanin
authors.affiliation: Department of Biology, University of Padova, Padova, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Caccin
authors.affiliation: Department of Biology, University of Padova, Padova, Italy.
authors.forename: Samantha
authors.initials: S
authors.lastname: Corrà
authors.affiliation: Department of Biology, University of Padova, Padova, Italy.
authors.forename: Cristiano
authors.initials: C
authors.lastname: De Pittà
authors.affiliation: Laboratory of Genetics, The Rockefeller University, New York, NY, USA.
authors.forename: Catharine
authors.initials: C
authors.lastname: Boothroyd
authors.affiliation: Department of Genetics, University of Leicester, Leicester, UK.
authors.forename: Edward W
authors.initials: EW
authors.lastname: Green
authors.affiliation: Department of Genetics, University of Leicester, Leicester, UK.
authors.forename: Charalambos P
authors.initials: CP
authors.lastname: Kyriacou
authors.affiliation: Department of Biology, University of Padova, Padova, Italy rodolfo.costa@unipd.it.
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Costa
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D001683:Biological Clocks; D002940:Circadian Rhythm; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics* / Q000502:physiology; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D017344:Genes, Insect; D056950:Period Circadian Proteins / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D013696:Temperature
chemical_list: D029721:Drosophila Proteins; C539040:PER protein, Drosophila; D056950:Period Circadian Proteins; D012333:RNA, Messenger; C096445:tim protein, Drosophila
keywords: Drosophila melanogaster; circadian rhythms; mRNA cycling; natural conditions; splicing