A Bombyx mori gene, BmChi-h, encodes a protein homologous to bacterial and baculovirus chitinases

Insect Biochem Mol Biol. 2003 Aug;33(8):749-59. doi: 10.1016/s0965-1748(03)00084-5.

Abstract

We have cloned and characterized a novel chitinase gene (BmChi-h) from the silkworm, Bombyx mori. BmChi-h cDNA has an open reading frame of 1,665 nucleotides, encoding a protein of 555 amino acid residues. The predicted protein shared extensive similarities with bacterial and baculovirus chitinases in both amino acid sequences (73% identity with Serratia marcescens chiA and 63% with Autographa californica nucleopolyhedrovirus chiA) and domain architectures. BmChi-h was a single-copy gene and located on chromosome 7. The expression of BmChi-h mRNA was observed in a stage- and tissue-specific manner that was almost identical to that of another chitinase gene previously cloned from B. mori. We further determined the overall genomic organization of BmChi-h. There was no intron in the ORF of BmChi-h. However, BmChi-h was transcribed from three promoters, which generated three isoforms in the 5'-UTR of the transcript. Phylogenetic analysis suggested that ancestral species of B. mori acquired the chitinase gene from a bacterium or an ancestral baculovirus via horizontal gene transfer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Bacterial Proteins / genetics*
  • Baculoviridae / chemistry
  • Baculoviridae / genetics*
  • Base Sequence
  • Biological Evolution
  • Blotting, Northern
  • Blotting, Southern
  • Bombyx / genetics*
  • Chitinases / genetics*
  • Cloning, Molecular
  • DNA, Complementary
  • Gene Transfer, Horizontal
  • Insect Proteins / genetics*
  • Molecular Sequence Data
  • Phylogeny
  • Polymerase Chain Reaction
  • Sequence Homology, Amino Acid

Substances

  • Bacterial Proteins
  • DNA, Complementary
  • Insect Proteins
  • Chitinases