Hunting for new spider silk genes in the black widow spider, Latrodectus hesperus

Spider silk has the potential to be used in many applications such as sutures, fishing nets, body armor and drug delivery systems. The purpose of the study was to find new silk genes by screening a cDNA library that was constructed from the silk-producing glands of the black widow spider,Latrodectus hesperus. To search for novel silk genes, we plated our cDNA library and randomly isolated individual plaques that carried different spider genes. In order to remove the spider genes from the viral chromosome, we coinfected bacteria with a single library virus along with a helper phage to excise a portion of the viral chromosome that corresponded to the spider gene and embedded plasmid. Following the excision process, these plasmids were transformed into bacteria, inoculated, then purified using traditional plasmid miniprep procedures. Restriction digestion was done to verify the presence of a cDNA insert (spider gene) and the plasmids that carried cDNA inserts were subject to DNA sequence analysis. Sequences were then analyzed using bioinformatics programs. After the analysis of over 50 different spider cDNAs, we found three interesting genes. Translation of the retrieved cDNA sequences indicated we found a novel silk fibroin, a glue protein, and a variant of the egg case fibroin TuSp1