Worm Breeder's Gazette 9(2): 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.
At the last worm meeting we reported the finding of a repetitive element in C. elegans that had strain number differences reminiscent of those found for the transposon Tc1. This new element was found in an experiment in which we looked for larger variants of Tc1, hoping to find a sequence that might be to Tc1 what the autonomous Ac element is to the non-autonomous Ds element in maize. Subsequent experiments in which we cloned several of the elements from Bergerac and Bristol phage libraries suggested that this is not the case. The new element, tentatively named Tc2, is not physically associated with Tc1 except in the single case in which we picked it up. Restriction maps of five of the members of the family do not reveal any simple pattern among them; e.g., they do not appear to be simple deletion variants of one 'master' form. We are currently pursuing a line of evidence which may enable us to prove conclusively that Tc2 is actively transposing in the germline of Bristol/Bergerac recombinants. A number of such recombinants were kindly sent to us by Ikue Mori and Don Moerman in Robert Waterston's lab at Washington University. These recombinants have either retained or lost a single well-mapped locus which confers germline transposition activity on Tc1 (as assayed by reversion of unc-22( st136::Tc1)). While doing Southern blot experiments to see if Tc1 activity correlates with a member of the Tc2 family, we noticed three cases in which recombinant strains contained Tc2 bands which are not present in either Bergerac or Bristol. It is possible that these bands represent new insertions into germline DNA. We are now cloning one of these bands in hopes of isolating an active version of Tc2. We will demonstrate that it is a new insertion (if it is) by using its flanking sequence to pull out its empty site from a parent strain.