Tremendous intron length differences of the BmKBT and a novel BmKBT-like peptide genes provide a mechanical basis for the rapid or constitutive expression of the peptides.
The cDNA sequence encoding a novel BmKBT-like peptide (referred to as BmKBy) was cloned and sequenced from the scorpion Mesobuthus martensii Karsch. Functional analysis indicated that both BmKBT and BmKBy possess strong toxicity in mice, but very weak toxicity in cotton bollworm. Phylogenetic analysis showed that BmKBy and BmKBT represent evolutionary intermediates between the α- and β-toxins from scorpions. The genomic sequences of BmKBT and BmKBy were also obtained. It is interesting to see that two genes, which contain an intron of 225 and 1529bp, respectively, exactly code for the BmKBT peptide. One gene, which contains an intron of 1312bp, codes for BmKBy. Given that genes with long introns favor constitutive expression, whereas those with short introns are rapidly regulated in response to stimulations, the BmKBT_a and BmKBT_b genes provide a mechanical basis for either constitutive expression or rapid generation of the toxic peptides in response to different signals.
Department of Biological Science and Technology, School of Environmental Studies & State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Wuhan), Wuhan 430074, China.
Yao
Y
Nie
Xian-Chun
XC
Zeng
Xuesong
X
Luo
Shifen
S
Wu
Lei
L
Zhang
Hanjun
H
Cao
Jianping
J
Zhou
Lingli
L
Zhou
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D007438:Introns; D007814:Larva / Q000187:drug effects; D007928:Lethal Dose 50; D051379:Mice; D008969:Molecular Sequence Data; D009036:Moths; D058974:Phylogeography; D014176:Protein Biosynthesis; D012604:Scorpion Venoms / Q000096:biosynthesis / Q000235:genetics* / Q000633:toxicity; D012605:Scorpions / Q000235:genetics*; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
C418407:KBT toxin, Buthus martensii; D012604:Scorpion Venoms