Worm Breeder's Gazette 11(4): 34
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 proretrovirus like element TAS is found in about 50 copies in the haploid genome of the nematode A. Lumbricoides. One complete copy was sequenced. The putative gag region near the 5' LTR contains a 1962 bp long open reading frame which codes for a RNA binding domain. Near the center of the element we found on the +1 frame (relative to the gag frame) a region which shares some characteristics with known pol genes. However, this part of the sequence is interrupted by four stop codons. One of the putative polypeptides contains.the amino acid sequence YVDN, a slightly mutated version of the box YXDD which is present in almost all known reverse transcriptases. We conclude that stop codons as well as the change in the sequence of the YXDD box are the result of occasional point mutations and that the sequenced element may represent a nonfunctional copy of TAS. The YVDN box is carboxyterminally flanked by a conserved RNase H and a zinc finger motif. The latter characterizes a possible endonuclease domain. A further 2061 base pair spanning ORF near the 3' LTR of TAS corresponds to an env region. TAS represents obviously a retrovirus related sequence with a similar gene arrangement as, e.g., that of the mobile element 17.6 in the Drosophila genome and that found in some genomes of retroviruses.