Mutations affecting the meiotic and mitotic divisions of the early Caenorhabditis elegans embryo.
We describe interactions between maternal-effect lethal mutations in four genes of Caenorhabditis elegans whose products appear to be involved in the meiotic and mitotic divisions of the one-cell embryo. Mitosis is disrupted by two dominant temperature-sensitive gain-of-function maternal-effect lethal mutations, mei-1(ct46) and mel-26(ct61), and by recessive loss-of-function maternal-effect lethal mutations of zyg-9. The phenotypic defects resulting from these mutations are similar. Doubly mutant combinations show a strong enhancement of the maternal-effect lethality under semipermissive conditions, suggesting that the mutant gene products interact. We isolated 15 dominant suppressors of the gain-of-function mutation mei-1(ct46). Thirteen of these suppressors are apparently intragenic, but 11 of them suppress in trans as well as cis. Two extragenic suppressors define a new gene, mei-2. The suppressor mutations in these two genes also result in recessive maternal-effect lethality, but with meiotic rather than mitotic defects. Surprisingly, most of these suppressors are also able to suppress mel-26(ct61) in addition to mei-1(ct46). The products of the four genes mei-1, mei-2, zyg-9 and mel-26 could be responsible for some of the specialized features that distinguish the meiotic from the mitotic divisions in the one-cell embryo.
Mains
P E
PE
Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder 80309.
Kemphues
K J
KJ
Sprunger
S A
SA
Sulston
I A
IA
Wood
W B
WB
D000483:Alleles; D000818:Animals; D002107:Caenorhabditis / Q000196:embryology / Q000235:genetics*; D002874:Chromosome Mapping; D004843:Epistasis, Genetic; D005796:Genes; D005808:Genes, Recessive; D008540:Meiosis / Q000235:genetics; D008938:Mitosis / Q000235:genetics; D009154:Mutation; D010641:Phenotype; D013489:Suppression, Genetic; D013696:Temperature