Fig. 4. Excess GLD-1 causes premature meiotic entry. (A) gld-1(oz10gf) has a smaller proliferative zone than wild-type animals. Dissected gld-1(oz10gf) and wild-type gonad arms from animals grown at 20°C to one day past L4, stained with REC-8- and HIM-3-specific antibodies, and DAPI. Proliferative zone defined as the number of cell diameters from the DTC that are REC-8-positive with all cells at that distance also REC-8-positive. n=15 per genotype. t-test P<10^–7. The oz10 allele contains a deletion in the gld-1 3'UTR, as well as a missense mutation in an amino acid conserved in some, but not all homologues (Jones and Schedl, 1995). The increased GLD-1 accumulation is probably due to the mutant 3'UTR causing increased translation (Crittenden et al., 2002). However, we cannot rule out the possibility that the missense mutation affects GLD-1 levels or GLD-1 activity. (B) gld-1(oz10gf) enhances the `Glp' phenotype of glp-1(bn18) at 20°C. The graph shows the percentage of animals that have lost their distal proliferative zones as measured by Nomarski microscopy. 40/40 unc-32(e189) glp-1(bn18) gonad arms had wild-type proliferative zones. For gld-1(oz10gf); unc-32(e189), 52/54 gonad arms had wild-type proliferative zones while 2/54 had smaller gonad arms with enlarged cells in the distal end. In gld-1(oz10gf); unc-32(e189) glp-1(bn18) animals, only 3/93 had large proliferative zones while the rest lacked a normal proliferative zone, with either sperm completely filling the distal end (85/93) or sperm with other larger cells (5/93). (C) Dissected gld-1(oz10gf); unc-32(e189) glp-1(bn18) adult hermaphrodite gonad arm stained with DAPI (blue) and SP56 monoclonal antibody (red), which is specific to male germ cells (Ward et al., 1986). Scale bar: 20 µm.