GLD-1, a Cytoplasmic Protein Essential for Oocyte Differentiation, Shows Stage- and Sex-Specific Expression duringCaenorhabditis elegansGermline Development

TLDR

GLD‑1 is a cytoplasmic RNA‑binding protein essential for oocyte differentiation in *C. elegans*, and loss of gld‑1 abolishes hermaphrodite oogenesis, producing a tumorous germline in which female germ cells exit meiosis and re‑enter the mitotic cycle.

Abstract

GLD-1, a putative RNA binding protein, is essential for oocyte development inCaenorhabditis elegans.Agld-1null mutation abolishes hermaphrodite oogenesis and confers a tumorous germline phenotype in which presumptive female germ cells exit the meiotic pathway and return to the mitotic cell cycle. Here we demonstrate thatgld-1(null)germ lines express female-specific, but not male-specific, molecular markers, indicating thatgld-1acts downstream of sexual fate specification to regulate oocyte differentiation. Immunolocalization studies identify GLD-1 as a cytoplasmic germline protein that displays differential accumulation during germline development. First, germ cells that are in the mitotic cell cycle contain low levels of GLD-1 that likely reflect a nonessentialgld-1function (negative regulation of proliferation in the mitotic germ line) revealed in previous genetic studies. Second, entry of presumptive oocytes into the meiotic pathway is accompanied by a strong increase in GLD-1 expression/accumulation. GLD-1 levels are high through the pachytene stage but fall to background as germ cells exit pachytene and complete oogenesis. The meiotic prophase accumulation pattern is consistent with GLD-1′s essential role in oocyte differentiation, which may be to repress the translation of a subset of maternal RNAs synthesized during early oogenesis until late oogenesis when GLD-1 is absent.