Worm Breeder's Gazette 10(1): 52
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
The Tc1 transposable element of C. elegans has been sequenced ( Rozenzweig and Hirsch, NAR 11, 4201). It is 1610bp long and contains one major ORF, encoding a 273 amino acid protein. All C. elegans strains contain copies of Tc1, though not all strains are active in transposition (e.g. the strain Bristol is inactive). The Bergerac strain shows active transposition of Tc1, and contains approximately 300 copies of Tc1 that seem to have (almost) all the same restriction pattern (Liao et al., PNAS 80, 3585). We are interested in the major ORF that -we think- may encode the transposase (TcA) of the element. I sequenced the TcA gene of an element that had inserted into the unc22 gene of the Bergerac strain (st137, kindly provided by Dr. D. Moerman). As shown below there are a few differences in the coding sequence. One of them is an amber triplet in this copy of the TcA gene, that results in a much shorter version of the gene. It has been suggested by several authors that the Tc1 activating gene in Bergerac may itself be a copy of Tc1. Possibly the difference between trans- active and inactive elements is not (like in the maize Ac/Ds system) in the size of the elements but in the primary sequence of the TcA. [See Figure 1]