Worm Breeder's Gazette 10(1): 35
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 unc-6 gene is required for guiding axons and migrating cells along the epidermis and for specifying certain epidermal cell fates. We have isolated two spontaneous unc-6 mutants, rh1035 and ev453, from the TR679 and RW7097 mutator strains, respectively. Using the flanking genes lev-9 and dpy-7 to select recombinants, the rh 1035 mutation was shown to be genetically inseparable from a Tc1 element contained in a 13 kb EcoRI fragment or a 2.8 kb XbaI fragment. The XbaI fragment was cloned into pUC19 and the Tc1 element excised with BalI. The resulting plasmid, pNJ6, retains an 18 bp palindrome derived from the terminal inverted repeats of the Tc1 element plus approximately 1200 bp of the presumptive unc-6 gene. When used as a probe for Southern analysis, the pNJ6 insert detects a 1.25 kb XbaI fragment in N2 Bristol DNA, a 2.8 kb fragment in both rh1035 and ev453 DNA, and a restored 1.25 kb fragment in DNA from spontaneous unc(+) revertants of both mutations. The insert detects an 11.5 kb EcoRI fragment in N2 Bristol DNA, a 13 kb fragment in rh1035 DNA, and two fragments of 6 and 7 kb in ev453 DNA. This suggests that Tc1(ev453) contains an internal EcoRI site. Spontaneous revertants of both rh1035 and ev453 restore the 11.5 kb EcoRI fragment observed in N2 Bristol. We have begun sequencing the pNJ6 insert. The site of Tc1(rh1035) insertion is 56 bp upstream of a consensus intron sequence suggesting that the element is in an unc-6 exon.