Characterization of a novel cDNA encoding a short venom peptide derived from venom gland of scorpion Buthus martensii Karsch: trans-splicing may play an important role in the diversification of scorpion venom peptides.
A novel cDNA clone (named BmKT-u) which is a hybrid molecule of the 5'-terminal region of BmKT' cDNA and the 3'-terminal region of an undocumented cDNA (named BmKu), was isolated from a cDNA library made from the venom gland of scorpion Buthus martensii Karsch. BmKT-u codes for a 30 amino acid residue precursor peptide composed of a 20-residue signal sequence, and a putative 10-residue novel mature peptide. Northern blot hybridization showed BmKT-u cDNA is generated from a transcript. RT-PCR experiments excluded the possibility that BmKT-u cDNA is an artifact generated during reverse transcription. Genomic amplifications performed with three pairs of BmKT-u gene-specific primers showed the BmKT-u gene does not exist in the genome of the scorpion as a single transcriptional unit. Genomic cloning for BmKT' showed that the BmKT' gene contains an intron of 509 bp inserted into the region encoding the C-terminal region of the signal peptide. A sequence alignment comparison of the cDNA of BmKT-u with genomic BmKT' revealed that the junction site of the hybrid molecule is located at the 5'-splicing site of the intron. The data suggest that the BmKT-u transcript is a naturally occurring mature mRNA that is generated by trans-splicing. Trans-splicing may contribute to the diversity of venom peptides from venomous animals.
Zeng
Xian-Chun
XC
State Key Laboratory of Virology, Institute of Virology, Department of Biotechnology, College of Life Sciences, Wuhan University, Wuhan 430072, PR China. andy88zeng@gmail.com
Luo
Feng
F
Li
Wen-Xin
WX
D000595:Amino Acid Sequence; D000818:Animals; D016477:Artifacts; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics*; D015723:Gene Library; D016678:Genome; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D012333:RNA, Messenger / Q000235:genetics; D012604:Scorpion Venoms / Q000737:chemistry / Q000235:genetics*; D012605:Scorpions / Q000033:anatomy & histology* / Q000737:chemistry / Q000235:genetics*; D016415:Sequence Alignment; D013698:Templates, Genetic; D020040:Trans-Splicing / Q000235:genetics*
D018076:DNA, Complementary; D010455:Peptides; D012333:RNA, Messenger; D012604:Scorpion Venoms