Worm Breeder's Gazette 12(3): 87 (June 15, 1992)

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 Transposable Element Tc1 Encodes a Protein that Specifically Binds to Tc1 DNA Ends

J. Chris Vos, Henri G.A.M. van Luenen, Jose T.M. Groenen, Ronald H.A. Plasterk

Figure 1

The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam

Originally a 273 triplet ORF has been identified in the first sequence of the transposable element Tc 1 of C. elegans (Rosenzweig et al., NAR 11: 4201, 1983). However, analysis of other Tc1 elements and a related element in C. briggsae suggested the presence of a longer ORF which would be interrupted by an intron (Schukkink and Plasterk, NAR 18: 895, 1990; Prasad et al., Genome 34: 6, 1991). Attempts to directly clarify the identity of the ORF by either RNA or protein analysis in C. elegans have been unsuccessful due to the very low level of expression. In order to increase the level of expression, we fused the most 5' ATG start codon in Tc1 to the hsp-16 promoter (Russnak et al., MCB 5: 1268, 1985). After establishing a transgenic worm with this construct, we analyzed the heat shock induced RNA. A 41 nt intron was removed from the primary transcripts for which the 3' splice site was as predicted previously [See Figure 1]. We conclude that Tc1 encodes a 343 amino acid polypeptide, the putative transposase, which we will refer to as Tc1A .Currently, we are investigating the expression of Tc 1 A in the transgenic worm and the effect on Tc1 transposition. We have expressed the 343 amino acid Tc1 A protein in E. coli. A soluble protein was partially purified and it could be shown by gel retardation assays that it binds in a sequence-specific fashion to the 55 bp inverted repeat of Tc1 .The binding properties of Tc1A will be further analyzed and the protein will be tested for its ability to act in an in vitro transposition assay either on its own or together with extracts prepared from C. elegans.

Literature Cited:

Rosenzweig et al., NAR 11: 4201, 1983

Schukkink and Plasterk, NAR 18: 895, 1990

Prasad et al., Genome 34: 6, 1991

Russnak et al., MCB 5: 1268, 1985

Figure 1