Purification and cDNA Cloning of Vitellogenin of the Wild Silkworm, Saturnia japonica (Lepidoptera: Saturniidae)

抄録

We purified the major yolk protein, vitellin, from Saturnia japonica, by column chromatographies. SDS-PAGE and immunoblot analysis of the S. japonica vitellin (SjVn) showed that SjVn consisted of only a large subunit with a molecular size of approximately 200kDa. We then cloned and sequenced cDNA of the S. japonica vitellogenin (SjVg), a SjVn precursor. The SjVg cDNA was 5731 nucleotides long and encoded 1776 amino acids for the entire subunit. The molecular weight of the predicted polypeptide was 200,000. Consensus motifs, such as GL/ICG (at the amino acid position 1592) and DGGR (located 17 residues upstream from the GL/ICG motif) were found in the deduced amino acid sequence. There is no RXRR motif, which is a cleavage site between the small and large subunits. Two polyserine regions were found in the deduced amino acid sequence.