Worm Breeder's Gazette 13(1): 34 (October 1, 1993)

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.

LINE like retrotransposon element in Caenorhabditis elegans

Sandra Youngman, Ronald H.A. Plasterk

Figure 1

Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam.

While sequencing the genomic prk-1 gene we found that it contains a large intron which is not A-T rich. It is 3.6 kb in length and it contains an open reading frame (in the opposite orientation of prk-1 )of 714 triplets. Searching the data bases with the ORF revealed that the sequence has homology with non LTR retrotransposons (LlNE-like elements) and highest homology with the rat retrotransposons L1 (L1-R: percentage identity 24% and percentage similarity 46%). The regions of strongest homology are at and around the amino acid domains of the reverse transcriptase sequence. Xiong and Eickbush 1990 (EMBO 9:3353-3362) have described 7 amino acid domains for reverse transcriptase. The figure shows the alignment of the putative retransposon element that we call rte-1 with L1 -Rand the seven amino acid domains of reverse transcriptase as described by Xiong and Eickbush. Non LTR retrotransposons lack long terminal repeats, but in contrast the element rte-1 is flanked by a 200 bp direct repeat of which 94 bp are also represented once in the cDNA clone of prk-1 .The significance of this direct repeat is unknown at present. As far as we know this retro-element is the first to be described in C. elegans. Work is in progress to determine the copy number of this element in C. elegans and to determine whether this element is present in other nematode species

Figure 1