Cloning and expression analysis of the Bombyx mori !-amylase gene (Amy) from the Indigenous Thai silkworm Strain, Nanglai

Abstract

″#$&′()*+(*,*,-$ $ -.*)./%$)*0-1*2%31-&%/+.4*(5′1,26 *7.*52) * (+& 89 - 1$.*Bombyx mori L. (Lepidoptera: Bombycidae), !″,$ %&′() is found in both digestive fluid and hemolymph. Here, the complete genomic sequence of the Amy gene encoding !″'$ %&′ from a local Thai silkworm, the Nanglai strain, was obtained. This gene was 7981 bp long with 9 exons. The full length Amy cDNA sequence was 1749 bp containing a 1503 bp open reading frame. The ORF encoded 500 amino acid residues. The deduced protein showed 8154% identity to other insect !″'$ %&′()s and more than 50% identity to mammalian enzymes. Southern blot analysis revealed that in the Nanglai strain Amy is a single-copy gene. RT- PCR showed that Amy was transcribed only in the foregut. Transgenic B. mori also showed that the Amy promoter activates expression of the transgene only in the foregut.