Worm Breeder's Gazette 10(2): 60
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 zyg-11 gene, on chromosome II, is required for proper cytoplasmic organization in early embryos. Mutations in the gene have a strict maternal-effect lethal phenotype. In embryos from zyg-11 mothers, meiosis arrests at metaphase II, there is a delay in the appearance of pronuclei, the position of the first cleavage furrow is abnormal, and P granules fail to segregate properly (Kemphues et al., Dev. Biol. 113, 449 (1986)). We believe that a molecular analysis of this gene will help us to understand the nature and function of maternally-encoded factors in the egg. To identify a zyg-11 clone, we made use of a 400kb contig from Alan Coulson and John Sulston that we thought likely to contain zyg-11. We had previously shown that the left-most cosmid of the contig overlapped the left end of mnDf103, and the remainder of the contig extended to the right on the genetic map ( toward zyg-11). The contig also covered the sites of 2 Tc1 elements identified in a mutator strain by Ikue Mori, Don Moerman and Bob Waterston (WBG 10 #1, p.47). Ikue kindly sent us a worm strain containing the two Tc1 's, and we showed by 3-factor crosses that zyg- 11 mapped to the left of Tc1 #40 (RW#200L). Therefore, zyg-11 had to be in the contig somewhere. We decided to find the position of zyg-11 in the contig by using individual cosmids as probes of a Southern blot containing DNA from 2 mut-2 induced zyg-11 mutants (it50 and it65) that we had found earlier. The first cosmid that we tested, DH11, must contain at least part of zyg-11 since it detected DNA rearrangements in both it50 and it65. The rearrangement in it50 appeared to be a 2.9kb insertion, while the rearrangement in it65 appeared to be a 1.6kb insertion. Both insertions occurred within a 3. 0kb EcoRI fragment. Additional Southern analysis narrowed down the points of insertion to an 800-base EcoRI-BglII fragment. We are now sequencing that fragment. We will also use the clone as a probe to study transcription of zyg-11. The cosmid DH11 also seems to cover an endpoint of mnDf104 since it detects a novel restriction fragment when used as a probe against mnDf104 DNA. The figure below shows some clones of the contig, along with some genetic markers. [See Figure 1]