Identification of vitellogenin gene from female Ascaris suum cDNA library using a PCR-based screening method.

The vitellogenin gene of female Ascaris suum was identified from a female A. suum specific subtractive cDNA library by PCR-based screening method using primers derived froma female A. suum-specific EST sequences. A positive clone F993-G10-A10 was obtained and sequenced. This clone contained 621 bp nucleotide encoding a protein homologous to the vitellogenin structural protein (yolk protein) family (Vit1,Vit2,Vit3,Vit4 and Vit5) in Caenorhabditis elegans,and shared 35%,35%,34%,34% and 35% amino acid identities with proteins,respectively. The PCR-based screening method was effective,simple and rapid for identifying genes from cDNA libraries.