This phenotypic mutant was identified in an ENU mutagenesis screen. The molecular lesion is a G-to-T transversion mutation at the 5' splice donor site of the 16th intron of the gene. Skipping of exon 16 in the encoded mRNA results in a frameshift in the coding sequence and the introduction of a premature stop codon. The encoded protein was not detectable in mutant fully grown oocytes, and the mutant mRNA was detectable only in trace amounts. (J:181834)