Dynein and MEL-28 contribute in parallel to oogenic maturity in C. elegans

dhc-1(or283ts); mel-28(t1684) double mutants have a severely reduced brood size compared to the wild-type and compared to each single mutant. To determine if this low-fecundity phenotype is associated with oocyte maturity defects, we used markers to assess the maturity of oocytes in the proximal gonad. We studied phosphorylated histone H3, a marker normally associated with mature oocytes, and DAO-5, a nucleolar marker normally associated with immature oocytes. We found that in the double mutants, the oocyte occupying the -1 position frequently retains DAO-5 and fails to accumulate phosphorylated histone H3. This suggests that the simultaneous disruption of dynein and MEL-28 can lead to failure of the oocyte maturity program.