Identification of crotasin, a crotamine-related gene of Crotalus durissus terrificus.
Crotamine is a cationic peptide (4.9 kDa, pI 9.5) of South American rattlesnake, Crotalus durissus terrificus' venom. Its presence varies according to the subspecies or the geographical locality of a given species. At the genomic level, we observed the presence of 1.8 kb gene, Crt-p1, in crotamine-positive specimens and its absence in crotamine-negative ones. In this work, we described a crotamine-related 2.5 kb gene, crotasin (Cts-p2), isolated from crotamine-negative specimens. Reverse transcription coupled to polymerase chain reaction indicates that Cts-p2 is abundantly expressed in several snake tissues, but scarcely expressed in the venom gland. The genome of crotamine-positive specimen contains both Crt-p1 and Cts-p2 genes. The present data suggest that both crotamine and crotasin have evolved by duplication of a common ancestor gene, and the conservation of their three disulfide bonds indicates that they might adopt the same fold as beta-defensin. The physiological function of the crotasin is not yet known.
Molecular Toxinology Laboratory, Butantan Institute, Av. Vital Brazil 1500, São Paulo 05503-900, Brazil. radisbra@butantan.gov.br
G
G
Rádis-Baptista
T
T
Kubo
N
N
Oguiura
A R B
AR
Prieto da Silva
M A F
MA
Hayashi
E B
EB
Oliveira
T
T
Yamane
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001938:Brazil; D003435:Crotalid Venoms / Q000235:genetics*; D017839:Crotalus / Q000235:genetics*; D017931:DNA Primers; D019143:Evolution, Molecular; D040461:Gene Components; D020869:Gene Expression Profiling; D015698:Genomic Library; D008969:Molecular Sequence Data; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
D003435:Crotalid Venoms; D017931:DNA Primers; C010563:crotamine