A naturally occurring non-coding fusion transcript derived from scorpion venom gland: implication for the regulation of scorpion toxin gene expression.
Scorpion venom glands synthesize and secrete a great number of low molecular mass toxic peptides for prey and defense. Many cDNAs and genomic genes encoding these toxins have been isolated and sequenced. However, their expression regulation mechanism is not yet known at present. During screening of a cDNA library prepared from venom glands of the scorpion Buthus martensii Karsch, we isolated a natural fusion cDNA composed of the 5'-untranslated region (UTR) and upstream coding sequence of a long-chain toxin transcript and the downstream coding sequence and 3'-UTR of a short-chain toxin transcript. The junction site is just the overlapping region of 11 nucleotides (GGCAAGGAAAT) between the two wild transcripts, and thus leads to the formation of an early stop codon, which will cause premature translation. Based on the above observations, combined with the genomic data, we proposed a characteristic regulation mechanism of scorpion toxin genes, in which trans-splicing and nonsense mediated mRNA decay are involved.
Zhu
S
S
Department of Biotechnology, College of Life Sciences, Wuhan University 430072, Wuhan, Hubei Province, PR China. shunyizhu@hotmail.com
Li
W
W
Cao
Z
Z
D020413:3' Untranslated Regions / Q000235:genetics; D020121:5' Untranslated Regions / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018389:Codon, Nonsense / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D022821:RNA Splice Sites / Q000235:genetics; D020871:RNA Stability; D012342:RNA, Small Nuclear / Q000235:genetics; D022661:RNA, Untranslated / Q000235:genetics*; D011995:Recombination, Genetic / Q000235:genetics; D012604:Scorpion Venoms / Q000378:metabolism*; D012605:Scorpions / Q000033:anatomy & histology / Q000235:genetics*; D020040:Trans-Splicing / Q000235:genetics; D014158:Transcription, Genetic / Q000235:genetics
D020413:3' Untranslated Regions; D020121:5' Untranslated Regions; D018389:Codon, Nonsense; D018076:DNA, Complementary; D022821:RNA Splice Sites; D012342:RNA, Small Nuclear; D022661:RNA, Untranslated; D012604:Scorpion Venoms; C405484:U2 small nuclear RNA