Worm Breeder's Gazette 13(3): 84 (June 1, 1994)

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.


Chaobo Guo, Edward Hedgecock

Department of Biology, Johns Hopkins University, Baltimore, MD 21218

Cell migration and cell fate determination are two important and interdependent events during animal development. In mig-5 mutants, we observe abnormal migrations and transformation in cell fates in a variety of lineages. The descendants of the QL neuroblast fail to migrate posteriorly, but migrate anteriorly instead. Distal tip cells (DTCs) leading the gonad arms make precocious dorsal turns or migrate along abnormal tracks. DTCs are frequently missing and occasionally a third DTC is present. Rarely, two anchor cells are present in the hermaphrodite gonad and often two linker cells are present in the male. In vulval equivalence group, one or two secondary vulval precursor cells (VPCs) are often missing, and in the pre-anal equivalence group, P12 usually adopts a P11 -likesecondary fate rather than its normal primary fate. Interestingly, in mig-5 ,both cell migration and cell fate are affected in single type of cell (DTC).

We have two EMS-induced alleles of mig-5 , rh94 and rh147 . rh147 is the stronger allele. The DTC phenotype of rh147 /Dfis similar to that of rh147 homozygotes, consistent with the possibility that rh147 is a null allele. The mig-5 mutation shows both maternal and zygotic sufficiency at least for Q cell and DTC phenotypes. Preliminary data also suggest that the mig-5 DTC phenotype is temperature-sensitive in both alleles.

mig-5 is immediately right of fer-15 and emb-27 on LGII in a region covered by cosmids or YACs. In deficiency tests, mig-5 is complemented by mnDf91 ,92, 94, 97, 98 and 109, but not complemented by mnDf84 ,93, 99, 101, 103, 104, 106 and 108. So far, we have used the cosmids spanning the left half of the zyg-11 -- zyg-9 region as probes looking for the deficiency endpoints. In addition to the Southern analysis, PCR and cosmid rescue techniques are also being used in the effort to clone the mig-5 gene.