title: Common evolution of waprin and kunitz-like toxin families in Australian venomous snakes.
abstract: The venoms of Australian snakes contain a myriad of pharmacologically active toxin components. This study describes the identification and comparative analysis of two distinct toxin families, the kunitztype serine protease inhibitors and waprins, and demonstrates a previously unknown evolutionary link between the two. Multiple cDNA and full-length gene isoforms were cloned and shown to be composed of three exons separated by two introns. A high degree of identity was observed solely within the first exon which coded for the propeptide sequence and its cleavage site, and indicates that each toxin family has arisen from a gene duplication event followed by diversification only within the portion of the gene coding for the functional toxin. It is proposed that while the mechanism of toxin secretion is highly conserved, diversification of mature toxin sequences allows for the existence of multiple protein isoforms in the venom to adapt to variations within the prey environment.
authors.affiliation: The Queensland Cancer Fund Research Unit, The Queensland Institute of Medical Research, Herston, Brisbane, Australia.
authors.forename: L
authors.initials: L
authors.lastname: St Pierre
authors.forename: S T
authors.initials: ST
authors.lastname: Earl
authors.forename: I
authors.initials: I
authors.lastname: Filippovich
authors.forename: N
authors.initials: N
authors.lastname: Sorokina
authors.forename: P P
authors.initials: PP
authors.lastname: Masci
authors.forename: J
authors.initials: J
authors.lastname: De Jersey
authors.forename: M F
authors.initials: MF
authors.lastname: Lavin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001315:Australia; D001483:Base Sequence; D018076:DNA, Complementary / Q000235:genetics; D004546:Elapid Venoms / Q000737:chemistry / Q000235:genetics*; D019143:Evolution, Molecular; D016678:Genome; D015151:Immunoblotting; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000235:genetics*; D011480:Protease Inhibitors / Q000737:chemistry*; D016415:Sequence Alignment
chemical_list: D018076:DNA, Complementary; D004546:Elapid Venoms; D010455:Peptides; D011480:Protease Inhibitors