From EST analysis to potential silk gene discovery

Abstract

Spider silks are renowned for their excellent mechanical properties. Although several spider fibroin genes, mainly from dragline and capture silks, have been identified, there are still many members in the spider fibroin gene family remain uncharacterized. In this study, a cDNA library from a pool of all seven silk glands from a local tropical species, Nephila antipodiana, was constructed and an expressed sequence tag (EST) approach was used to isolate genes involved in spider silk production, approximately 1000 clones with inserts of 1 Kb were selected for sequencing. A novel silk cDNA clone from the golden web spider Nephila antipodiana was isolated, both in situ hybridization and immunoblot analyses have shown that it is specifically expressed in the tubuliform gland and likely encodes one fibroin protein from the tubuliform gland, which supplies the main component of the inner egg case. In addition, some other clones with novel repetitive amino acid sequences are described.