Worm Breeder's Gazette 9(2): 73

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.

Isolation of Maternal Effect Lethal Mutations in mut-2(r459) and mut-3(r456) Backgrounds

D. Levitan and D. Stinchcomb

We have utilized a screen for maternal effect lethal mutations (
Preiss, J., Kemphues, K., Wolf, N., and Hirsh, D.  (1984) WBG 8(2),5) 
to search for mutations that may be due to Tc1 transposition.  The egg-
laying defective mutation, egl-23 (n601) IV, was crossed into strains 
bearing the mutators mut-2 (r459) or mut-3 (r456) (Phil Anderson, 
Bonnie Saari, and John Collins (1985) WBG 9(1), 29).  New maternal 
effect mutations that arose during propagation were identified as 
heterozygotes: 1/4 of their progeny produced dead eggs and were not 
consumed by larva (they did not 'bag').  In our preliminary screens, 
we picked 1500 egl-23; and 600 egl-23;mut-3 
worms.   We identified three maternal effect mutations in the mut-2 
background: jb2, jb3, and jb7.  Homozygous jb2 hermaphrodites will 
produce a few progeny (~1-10) inevitably sterile.  Early divisions of 
eggs from which are jb2 hermaphrodites are symmetric and synchronous, 
reminiscent of mutations in the par loci.  Indeed, jb2 fails to 
complement par-2 (it5) III (Niansheng Cheng, Diane Morton, and Ken 
Kemphues, this issue).  Hermaphrodites homozygous for the mutation jb3 
(which maps to chromosome III) produce eggs with variable terminal 
phenotypes; no clear defect in early divisions can be seen.  Strains 
homozygous for the jb7 mutation produce eggs whose early divisions are 
far slower than wild type.  We've isolated one maternal effect 
mutation from the mut-3 background, jb6.  The jb6 mutants produce eggs 
whose first observable defects are in gastrulation and/or the timing 
of the second round of division of the E lineage.  Genetic and 
molecular analysis of these maternal effect alleles and screens to 
identify additional mutations are in progress.