title: Two novel doubletime mutants alter circadian properties and eliminate the delay between RNA and protein in Drosophila.
abstract: Phosphorylation is an important feature of pacemaker organization in Drosophila. Genetic and biochemical evidence suggests involvement of the casein kinase I homolog doubletime (dbt) in the Drosophila circadian pacemaker. We have characterized two novel dbt mutants. Both cause a lengthening of behavioral period and profoundly alter period (per) and timeless (tim) transcript and protein profiles. The PER profile shows a major difference from the wild-type program only during the morning hours, consistent with a prominent role for DBT during the PER monomer degradation phase. The transcript profiles are delayed, but there is little effect on the protein accumulation profiles, resulting in the elimination of the characteristic lag between the mRNA and protein profiles. These results and others indicate that light and post-transcriptional regulation play major roles in defining the temporal properties of the protein curves and suggest that this lag is unnecessary for the feedback regulation of per and tim protein on per and tim transcription.
authors.affiliation: Graduate Departments of Biochemistry and Biology, Howard Hughes Medical Institute, and National Science Foundation Center for Biological Timing, Brandeis University, Waltham, Massachusetts 02454, USA.
authors.forename: V
authors.initials: V
authors.lastname: Suri
authors.forename: J C
authors.initials: JC
authors.lastname: Hall
authors.forename: M
authors.initials: M
authors.lastname: Rosbash
mesh_terms: D000483:Alleles; D000818:Animals; D001683:Biological Clocks / Q000502:physiology; D048149:Casein Kinase 1 epsilon; D002940:Circadian Rhythm / Q000235:genetics*; D003624:Darkness; D004330:Drosophila; D029721:Drosophila Proteins; D005246:Feedback; D005786:Gene Expression Regulation; D019476:Insect Proteins / Q000378:metabolism; D008027:Light; D009687:Nuclear Proteins / Q000378:metabolism; D056950:Period Circadian Proteins; D010766:Phosphorylation; D011494:Protein Kinases / Q000096:biosynthesis* / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism*; D013997:Time Factors
chemical_list: D029721:Drosophila Proteins; D019476:Insect Proteins; D009687:Nuclear Proteins; C539040:PER protein, Drosophila; D056950:Period Circadian Proteins; D012333:RNA, Messenger; C113519:dco protein, Drosophila; C096445:tim protein, Drosophila; D011494:Protein Kinases; D048149:Casein Kinase 1 epsilon