A variant Tc4 transposable element in the nematode C. elegans could encode a novel protein.
A variant C. elegans Tc4 transposable element, Tc4-rh1030, has been sequenced and is 3483 bp long. The Tc4 element that had been analyzed previously is 1605 bp long, consists of two 774-bp nearly perfect inverted terminal repeats connected by a 57-bp loop, and lacks significant open reading frames. In Tc4-rh1030, by comparison, a 2343-bp novel sequence is present in place of a 477-bp segment in one of the inverted repeats. The novel sequence of Tc4-rh1030 is present about five times per haploid genome and is invariably associated with Tc4 elements; we have used the designation Tc4v to denote this variant subfamily of Tc4 elements. Sequence analysis of three cDNA clones suggests that a Tc4v element contains at least five exons that could encode a novel basic protein of 537 amino acid residues. On northern blots, a 1.6-kb Tc4v-specific transcript was detected in the mutator strain TR679 but not in the wild-type strain N2; Tc4 elements are known to transpose in TR679 but appear to be quiescent in N2. We have analyzed transcripts produced by an unc-33 gene that has the Tc4-rh1030 insertional mutation in its transcribed region; all or almost all of the Tc4v sequence is frequently spliced out of the mutant unc-33 transcripts, sometimes by means of non-consensus splice acceptor sites.
Department of Genetics and Cell Biology, University of Minnesota, St Paul 55108.
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Shaw
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D017173:Caenorhabditis elegans / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins; D004247:DNA; D004251:DNA Transposable Elements; D015801:Helminth Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D012326:RNA Splicing; D012091:Repetitive Sequences, Nucleic Acid; D014158:Transcription, Genetic
D029742:Caenorhabditis elegans Proteins; D004251:DNA Transposable Elements; D015801:Helminth Proteins; C079857:Tc4-rh1030 protein, C elegans; D004247:DNA