Worm Breeder's Gazette 14(2): 27 (February 1, 1996)
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.
Department of Biology, McGill University, Montreal H3A1B1, PQ, Canada
In the course of narrowing the unc-14 rescuing region to a 5.2 kb Hind III - Sal I fragment that is mostly occupied by part of the YK363 gene (see also Ogura and Ohshima WBG 14(1) p51), we came across two unusual clones. We had established a restriction map across a 60 kb region, with particular attention to Eco RI sites, and had obtained 8 clones from this region from the LMB, which we mapped and tested for rescue. The first unusual clone, P1a74 (which uses a P1 phage-derived vector), was a clone which should have rescued. This clone has a wild-type restriction map, and the 11 kb Eco RI fragment which contains unc-14(+) is in the middle of this clone. However, 3/3 lines (and 18 F1 Rol) carrying this clone were not rescued, not even partially (since Unc-14 adults are strongly paralyzed this is a sensitive test). This suggests that the clone is not faithful to the genomic sequence and contains a mutation which completely inactivates unc-14(+). Of course this could just be a sporadic case, but we wonder if anyone else has noticed any odd behaviour of P1 clones? The other clone was cosmid K06F6. This clone rescues, but appeared on first inspection to be a chimera. It is a full-length cosmid and contains 7 contiguous Eco RI fragments from the unc-14 region spanning 24.5 kb, but at least 4 fragments clearly do not come from this region. There are also at least 4 Hind III fragments in this clone not shared by overlapping clones. The original fingerprint of this clone, however, does not appear problematic (Alan Coulson, pc). The simplest explanation is that this clone has rearranged without an apparent net loss of DNA. Bizarre.