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General Comment |
Jones AR, et al reported that
GLD-1, a cytoplasmic protein essential for oocyte differentiation,
shows stage- and sex-specific expression during Caenorhabditis
elegans germline development.
GLD-1, a putative RNA binding protein, is essential for oocyte development in
Caenorhabditis elegans. A gld-1 null 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. Gld-1(null) germ lines express female-specific, but not male-specific, molecular
markers, indicating that gld-1 acts 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 nonessential gld-1 function (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.
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