Studies On Sex-lethal Gene Of Bombyx Mori And Bombyx Mandarina

The sex of female silkworm is determined by ZW chromosomes. The Fem gene hasnot been found up to now. Sxl gene of Drosophila plays a central role in sex-determiningpathway. Bm-Sxl of silkworm was published on NCBI web in 2006. RT-PCR was used tostudy the expression in different tissues at different times and sex differential expression todiscuss the function of Bm-Sxl in silkworm. The results probably can provide clues to findthe Fem gene.Silkworm Bm-Sxl gene did not expresse in midgut, but expressed in ovaries of fifthinstar silkworm and pupae of all stages, and there was no obviously difference. But in thefat body and blood of mature silkworm, the expression abundance was much lower thanthat of other periods obviously. Silkworm Bm-Sxl gene did not expresse in virgin motheggs and half-hour eggs. But it was detected in thirty-hour eggs. Before this time, theembryos of silkworm had developed into blastocyst. Sxl differential expression at the eggstage showed that expressional difference existed between male and female. The resultsshowed that silkworm Bm-Sxl gene was possibly related to sex-determining.Two DNA fragments of wild silkworm Bmand-Sxl gene were obtained. Theamplified fragments were 1 218 bp and 1 279 bp, which only had 11 and 7 bases differentfrom silkworm Bm-Sxl gene. Sequence homologous was 99.1% and 99.4% separately.Speculated fusion Protein contained 341 amino acid residues. Molecular weight was 37.77k. The destination band was detected by SDS-PAGE and Western blotting. The fusionprotein was expressed successfully, which provides the condition to study the proteinfunction In vitro.