Structure and chromosomal localization of the gene for crotamine, a toxin from the South American rattlesnake, Crotalus durissus terrificus.
Crotamine is a 42 amino acid-long basic polypeptide, one of the major components of the South American rattlesnake, Crotalus durissus terrificus, venom. The mRNA has about 340 nucleotides and codifies a pre-crotamine, including the signal peptide, the mature crotamine, and a final lysine. In this report, we describe the crotamine gene with 1.8 kb organized into three exons separated by a long phase-1 (900 bp) and a short phase-2 (140 bp) introns. Exon 1 includes the 5'-untranslated region and codifies the first 19 amino acids of the signal peptide. Exon 2 codifies 42 amino acids, three belonging to the signal peptide and 39 to the mature crotamine. Exon 3 codifies the last three amino acids of the mature toxin and the terminal lysine. The crotamine gene was mapped by in situ hybridization to the end of the long arm of chromosome 2, the intensity of signals differing between the two homologues. This may reflect a difference in gene copy numbers between chromosomes, a possible explanation for the variable amounts of crotamine found in the venom.
Rádis-Baptista
Gandhi
G
Laboratório de Toxinologia Molecular, Instituto Butantan, Av. Vital Brazil, 1500, São Paulo 05503-900, Brazil.
Kubo
Tai
T
Oguiura
Nancy
N
Svartman
Marta
M
Almeida
Therezinha M B
TM
Batistic
Radenka F
RF
Oliveira
Eduardo B
EB
Vianna-Morgante
Angela M
AM
Yamane
Tetsuo
T
D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D003435:Crotalid Venoms / Q000737:chemistry / Q000235:genetics*; D017839:Crotalus; D018076:DNA, Complementary / Q000737:chemistry; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000032:analysis*; D016415:Sequence Alignment
D003435:Crotalid Venoms; D018076:DNA, Complementary; D012333:RNA, Messenger; C010563:crotamine