Worm Breeder's Gazette 10(2): 132
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.
As reported in the last WBG, Southern blots of EcoRI/PstI digests made from a TR679-derived unc-33 mutant showed two extra Tc4- containing bands (Tc4 is itself cut by PstI), and the bands were eliminated by reversion of the unc-33 mutation. We cloned one of these bands, a 1.7 kb fragment, and then used EcoRI plus XbaI to release a 0.6 kb unique worm sequence. When this 0.6 kb fragment was used to probe Southern blots of EcoRI digests, the unc-33 mutant DNA showed a 6.2 kb band, whereas N2 and several independent revertants of unc-33 showed a 4.2 kb band. The 0.6 kb probe was then used to screen an N2 genomic library (from Chris Link). A positive lambda recombinant phage was identified, and a 4.2 kb EcoRI fragment was subcloned from it. This fragment as probe identified the expected EcoRI bands from unc-33 strains, revertants and N2. In addition, it identified two EcoRI bands, 3.1 kb and 4.6 kb, from an unc-33 mutant kindly sent to us by Ed Hedgecock. Ed also sent us a revertant of his mutant; it has only the normal 4.2 kb EcoRI band. Thus the two mutants have different insertions in the same 4.2 kb EcoRI fragment. We have not yet determined the identity of the second insertion. In our effort to clone unc-3, we have identified an extra Tc1- containing BamHI fragment that is associated with an unc-3 mutation derived from TR679. Revertants of this allele in a largely-TR674 genetic background have recently been obtained and arise at a frequency in the range of 10+E-3-10+E-4. The revertants should now help determine if the Tc1-containing BamHI fragment we have focused on is responsible for the unc-3 mutation. In the last WBG we noted that we are generating a collection of TR679-derived mutants that are defective in the uptake of FITC. We now have a total of nine mutations: three on LGI, two on LGII, one on LGV, two on X, and one as yet unassigned to a linkage group. Mutations assigned to genes include a previously described daf-10 allele, a che-2 X allele, and a mutation that defines a new gene on X, which we propose calling ftc-1, located near and to the right of dpy-6.