Worm Breeder's Gazette 9(3): 91
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.
In the last WORM BREEDER'S GAZETTE (Vol. 9, NO. 2, p.63), we reported on five genetic loci affecting the embryonic migration of the neurons CAN, HSN, and ALM. Since then we have more closely examined ( Nomarski of newly-hatched L1's) the cellular phenotype of one mutation, mig-3(ct73)V, that appeared to affect only CAN migration with high penetrance. We have found that ALM is misplaced toward the anterior with low penetrance in mig-3(ct73)V, and we have also discovered a possible effect on the embryonic migration of M, the postembryonic mesoblast. In 2 of 17 animals examined a nucleus with the morphology characteristic of M was found misplaced. In one animal it was found misplaced toward the anterior and in the other it was found to be in its proper position along the anterior-posterior axis, but on the left side of the intestine. In 7 of the 17 animals examined, M was not seen, suggesting more drastic misplacement. We have also constructed the double mutant mig(ct78)III;vab- 8(ct33)V ) ln previously as mig(7a)III] and examined its cellular phenotype in newly-hatched L1's. Both single mutants affect CAN migration primarily. In the double mutant, only CAN migration is apparently affected with high penetrance. On all 9 sides examined CAN is not seen, suggesting that it is misplaced over the nerve ring as in vab- 8(ct33). ALM was found misplaced toward the anterior on 2 of 9 sides examined. In the future, we would like to define the null phenotypes of the mig loci we are currently studying (only for vab-8 do we know that the alleles we have studied behave like nulls when placed over a deficiency). Knowledge of null phenotypes will be useful both for defining more precisely the roles of these loci in embryonic cell migrations and in planning strategies for isolating Tc1-induced alleles for use in possible cloning.