A Caenorhabditis elegans wee1 homolog is expressed in a temporally and spatially restricted pattern during embryonic...

A wee1 homolog, wee-1.1, is expressed in both a temporally and spatially restricted pattern during early Caenorhabditis elegans embryogenesis, and is undetectable throughout the remainder of embryogenesis. The wee-1.1 message appears to be zygotically expressed in the somatic founder cell E of the 12-cell embryo. This expression disappears when the E blastomere divides for the first time. The wee-1.1 message then appears transiently in the nuclei of the eight great-granddaughter cells of the AB somatic founder cell, just before these cells divide in the 16-cell embryo. Following this division, the wee-1.1 mRNA is no longer detectable throughout the remainder of embryogenesis. The expression of wee-1.1 in the E blastomere and in the AB progeny appears to be restricted to nuclei in prophase and metaphase of the cell cycle. Analysis of the wee-1.1 mRNA expression pattern in maternal-effect lethal mutants suggests that this expression pattern is restricted to cells of the E and AB fates in the early embryo. This mRNA expression pattern is restricted to a 10-15-min span of embryonic development and may be regulating the timing of crucial cell divisions at this early stage of development.