A homologue of the Drosophila doublesex gene is transcribed into sex-specific mRNA isoforms in the silkworm, Bombyx mori

Comp Biochem Physiol B Biochem Mol Biol. 2001 Jan;128(1):145-58. doi: 10.1016/s1096-4959(00)00304-3.


The doublesex (dsx) gene is known as the final gene of the sex-determining cascade in Drosophila melanogaster. We have isolated a homologue of dsx in the silkworm, Bombyx mori, which has an epistatic feminizing gene located on the W chromosome. RT-PCR analysis indicated that B. mori dsx (Bmdsx) was transcribed in all the examined tissues, and the size of the amplified products was different between males and females. In Northern blot hybridization of poly(A)(+) RNA, the Bmdsx probe also detected a band with a sex-specific size difference. The male-specific cDNA lacked the sequence between 713 and 961nt of the female-specific cDNA. An RNase protection assay indicated that this sequence was male-specifically removed from the Bmdsx pre-mRNA. Southern blot analysis showed that Bmdsx is present at a single copy in the genome. These results suggested that the primary Bmdsx transcript is alternatively spliced to yield male- and female-specific mRNA isoforms. These sex-specific isoforms encode polypeptides with a common amino-terminal sequence but sex-specific carboxyl termini. DNA binding domain (DM domain) of BmDSX has 80% identity with D. melanogaster DSX proteins. These results suggest the Bmdsx would also regulate sexual differentiation, as does the Drosophila dsx gene.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternative Splicing
  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Blotting, Northern
  • Blotting, Southern
  • Bombyx
  • Chromosomes / metabolism
  • DNA, Complementary / metabolism
  • DNA-Binding Proteins / biosynthesis
  • DNA-Binding Proteins / chemistry
  • DNA-Binding Proteins / genetics*
  • Drosophila / genetics*
  • Drosophila Proteins*
  • Expressed Sequence Tags
  • Female
  • Gene Library
  • Insect Proteins / biosynthesis
  • Insect Proteins / chemistry
  • Insect Proteins / genetics*
  • Male
  • Models, Genetic
  • Molecular Sequence Data
  • Protein Isoforms
  • RNA / metabolism
  • RNA, Messenger / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Ribonucleases / metabolism
  • Sequence Homology, Amino Acid
  • Sequence Homology, Nucleic Acid
  • Sex Determination Processes
  • Sex Factors
  • Testis / metabolism
  • Time Factors
  • Tissue Distribution
  • Transcription, Genetic


  • DNA, Complementary
  • DNA-Binding Proteins
  • DSX protein, Drosophila
  • Drosophila Proteins
  • Insect Proteins
  • Protein Isoforms
  • RNA, Messenger
  • RNA
  • Ribonucleases