In many animal species, oocytes arrest in meiosis until they are fertilized. As oocytes age, changes occur in their cytoplasm, and fertility diminishes. Our goal is to better understand the regulation and function of ribonucleoprotein (RNP) and membrane remodeling in the oocytes of Caenorhabditis nematodes that are either arrested in meiosis or exposed to stress. The assembly of large RNP granules is hypothesized to maintain oocyte quality by regulating mRNA stability or translation (Jud et al., 2008). Increased blebbing of nuclear membranes also occurs in these oocytes, along with the assembly of annulate lamellae (Patterson et al., 2011). The remodeling of nuclear membranes into blebs in meiotically-arrested or heat-stressed oocytes correlates with the remodeling of RNPs and the formation of annulate lamellae at the oocyte cortex. Our current experiments are leveraging the discovery of large stacks of annulate lamellae in
cgh-1 and
ifet-1 oocytes. We are assessing the extent of nuclear blebbing in these, and related CGH-1 complex mutants, and so far have discovered increased blebbing in a subset of the mutants. We are also using TEM and the SP12::GFP strain to analyze membranes at the oocyte cortex and throughout the germ line. In addition to stacks of aligned membranes visualized by TEM in the mutant germ lines, we also observe large patches of ER membrane in oocytes and in the distal core. In combination with analyses of RNP granules, our results will address the hypothesis that nuclear blebbing initiates the formation of AL at the oocyte cortex, which in turn promotes the assembly of RNP granules.