title: Evidence from Multiple Species that Spider Silk Glue Component ASG2 is a Spidroin.
abstract: Spiders in the superfamily Araneoidea produce viscous glue from aggregate silk glands. Aggregate glue coats prey-capture threads and hampers the escape of prey from webs, thereby increasing the foraging success of spiders. cDNAs for Aggregate Spider Glue 1 (ASG1) and 2 (ASG2) have been previously described from the golden orb-weaver, Nephila clavipes, and Western black widow, Latrodectus hesperus. To further investigate aggregate glues, we assembled ASG1 and ASG2 from genomic target capture libraries constructed from three species of cob-web weavers and three species of orb-web weavers, all araneoids. We show that ASG1 is unlikely to be a glue, but rather is part of a widespread arthropod gene family, the peritrophic matrix proteins. For ASG2, we demonstrate its remarkable architectural and sequence similarities to spider silk fibroins, indicating that ASG2 is a member of the spidroin gene family. Thus, spidroins have diversified into glues in addition to task-specific, high performance fibers.
authors.affiliation: University of California, Riverside, Department of Biology, Riverside, California 92521, United States.
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Collin
authors.affiliation: University of California, Riverside, Department of Biology, Riverside, California 92521, United States.|Washington and Lee University, Department of Biology, Lexington, Virginia 24450, United States.
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Clarke
authors.affiliation: Washington and Lee University, Department of Biology, Lexington, Virginia 24450, United States.
authors.forename: Nadia A
authors.initials: NA
authors.lastname: Ayoub
authors.affiliation: University of California, Riverside, Department of Biology, Riverside, California 92521, United States.
authors.forename: Cheryl Y
authors.initials: CY
authors.lastname: Hayashi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019143:Evolution, Molecular; D005349:Fibroins / Q000235:genetics*; D023281:Genomics; D017386:Sequence Homology, Amino Acid; D047011:Silk / Q000235:genetics*; D013045:Species Specificity; D013112:Spiders
chemical_list: D047011:Silk; D005349:Fibroins