Comparison of chromosomal DNA composing timeless in Drosophila melanogaster and D. virilis suggests a new conserved structure for the TIMELESS protein.
Two proteins, TIM and PER, physically interact to control circadian cycles of tim and per transcription in Drosophila melanogaster. In the present study the structure of TIM protein expressed by D. virilis was determined by isolation and sequence analysis of genomic DNA (gDNA) corresponding to the D. virilis tim locus (v tim ). Comparison of v tim and m tim gDNA revealed high conservation of the TIM protein. This contrasts with poor sequence conservation previously observed for the TIM partner protein PER in these species. Inspection of the v tim sequence suggests an alternative structure for most TIM proteins. Sequences forming an intron in a previously characterized D. melanogaster tim cDNA appear to be most often translated to produce a longer TIM protein in both species. The N-terminal sequence of vTIM and sequence analysis of genomic DNA from several strains of D. melanogaster suggest that only one of two possible translation initiation sites found in tim mRNA is sufficient to generate circadian rhythms in D. melanogaster. TIM translation may be affected by multiple AUG codons that appear to have been conserved in sequences composing the 5'-untranslated tim mRNA leader.
Myers
M P
MP
National Science Foundation Science and Technology Center for Biological Timing and Laboratory of Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.
Rothenfluh
A
A
Chang
M
M
Young
M W
MW
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001683:Biological Clocks; D002940:Circadian Rhythm; D018387:Codon, Initiator; D004247:DNA; D004330:Drosophila; D029721:Drosophila Proteins; D004331:Drosophila melanogaster; D019476:Insect Proteins / Q000737:chemistry* / Q000235:genetics; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics; D056950:Period Circadian Proteins; D015183:Restriction Mapping; D016415:Sequence Alignment
D018387:Codon, Initiator; D029721:Drosophila Proteins; D019476:Insect Proteins; D009687:Nuclear Proteins; C539040:PER protein, Drosophila; D056950:Period Circadian Proteins; C096445:tim protein, Drosophila; D004247:DNA