|Budget Amount *help
¥14,400,000 (Direct Cost: ¥14,400,000)
Fiscal Year 2001: ¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2000: ¥10,900,000 (Direct Cost: ¥10,900,000)
An orthologue for clock (BmClock), a Drosophila circadian clock gene, was found in the Bombyx mori EST database. The nucleotide sequence of the BmClock cDNA was determined. The full length cDNA was 7521 bp in length and encoded a putative 585 amino acid sequence, which contained three conserved domains, a basic helix-loop-helix, PAS-1, and PAS-2. BmClock mRNA was expressed with circadian rythmicity, and the mRNA peak was observed in the evening.
We also found an orthologue (BmCry-α) of mammalian cryptochrome genes in the B. mori EST database. The cDNA was 4509 bp in length and encoded a complete 730-amino acid protein. The aa sequence conserved the domains for binding to DNA, MTHF, and FAD, respectively. Another kind of cryptochrome-like sequence was also found in the ESTs, it was an orthologue of the Drosophila cryptochrome gene. The length of cDNA was 1587 bp. It encoded 308 amino acid residues. RT-PCR analyzes of the brains demonstrated that both two chryptochrome mRNAs are expressed in a circadian fashion, and their peak appeared in the night. Another kind of cryptochrome (BmCry-γ) has just been found i as an EST. Additionally a member of the DNA 6-4 photolyase gene family (including cryptochromes) was found.
The cDNA microarray was utilized to find circadian rhythm in the larval fat body of B. mori. We found 11 genes that expressed mRNAs in the circadian fashion. On the other hand, we also did a crossing experiment between a polyvoltine strain and a bivoltine strain, and found that not only sex-linked gene but also autosomal gene(s) regulates the photoperiodism.