Identification and expression analysis of vitellogenin from silk-producing insect, <i>Actias selene</i> Hubner

Abstract

This study mainly shows the DNA sequence and expression analysis of vitellogenin in Actias selene (Ash-Vg). Specific primers were designed to amplify Ash-Vg gene by polymerase chain reaction (PCR) and the obtained DNA sequence was 7329 bp long, including 6 exons and 5 introns with an open reading frame encoding a 1774 amino acids peptide. A Bm DSX binding site and some conserved signatures such as CdxA and GATA-X were found in the 5Œ-flanking region of Ash-Vg gene. Meanwhile, the cDNA
encoding the small subunit of Ash-Vg protein was obtained by PCR and ligated to pET-28a vector for protein expression. A 45 KD recombinant protein was successfully expressed in Escherichia coli cells which were confirmed by sodium dodesyl sulfate- polyacrylamide gel electrophoresis (SDS-PAGE) and western blot analysis. The semi-quantitative PCR was also carried out to explore the specific expression of Ash-Vg and the results showed that the Ash-Vg gene expressed differently in various  developmental stages and tissues.

Key words: Actias selene Hubner, vitellogenin, DNA sequence, expression.