The mechanism of sex-specific splicing at the doublesex gene is different between Drosophila melanogaster and Bombyx mori.
We have previously reported that Bmdsx, a homologue of the sex-determining gene, doublesex (dsx), was found to be sex-specifically expressed in various tissues at larval, pupal, and adult stages in the silkworm, Bombyx mori, and was alternatively spliced to yield male- and female-specific mRNAs. To reveal sex-specific differences in splicing patterns of Bmdsx pre-mRNA, the genomic sequence was determined and compared with male- and female-specific Bmdsx cDNA sequences. The open reading frame (ORF) consisted of five exons. Exons 3 and 4 were specifically incorporated into the female type of Bmdsx mRNA. On the other hand, exon 2 was spliced to exon 5 to produce the male type mRNA of Bmdsx. As in the case of Drosophila dsx, the OD2 domain was separated by a female-specific intron into sex-independent and sex-dependent regions. Sex-specific splicing occurred in equivalent positions in the Drosophila dsx gene. However, unlike Drosophila dsx, the female-specific introns showed no weak 3' splice sites, and the TRA/TRA-2 binding site related sequences were not found in the female-specific exon, nor even in any other regions of the Bmdsx gene. Moreover, an in vitro splicing reaction consisting of HeLa cell nuclear extracts showed that the female-type of Bmdsx mRNA represented the default splicing. These findings suggest that the structural features of the sex-specific splicing patterns of Bmdsx pre-mRNA are similar to those of Drosophila dsx but the regulation of sex-specific alternative splicing of Bmdsx pre-mRNA is different.
Suzuki
M G
MG
Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, 113-8657, Tokyo, Japan.
Ohbayashi
F
F
Mita
K
K
Shimada
T
T
D017398:Alternative Splicing; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D012831:Bombyx / Q000235:genetics*; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000235:genetics*; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics*; D005091:Exons; D017344:Genes, Insect; D006367:HeLa Cells; D006801:Humans; D019476:Insect Proteins / Q000235:genetics*; D007438:Introns; D008969:Molecular Sequence Data; D014176:Protein Biosynthesis; D022821:RNA Splice Sites; D012333:RNA, Messenger; D012261:Ribonucleoproteins / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D012737:Sex Factors; D024363:Transcription Initiation Site
C442431:Bmdsx protein, Bombyx mori; D004268:DNA-Binding Proteins; C070369:DSX protein, Drosophila; D029721:Drosophila Proteins; D019476:Insect Proteins; D022821:RNA Splice Sites; D012333:RNA, Messenger; D012261:Ribonucleoproteins; C066174:tra2 protein, Drosophila