aph-2, but not aph-1, hermaphrodites maintain a GLP-1/Notch-dependent germline PZ in adulthood. a) Examples of dissected DAPI-stained gonads from staged hermaphrodites. The PZ contains undifferentiated germ cell nuclei between the distal end of the gonad (asterisk) and the distal side of the meiotic transition zone (straight dashed line) where leptotene nuclei are visible. Metaphase nuclei (arrow) are observed in the PZ. At the L4 stage (left), aph-2 and N2 have a robust PZ. In contrast, most aph-1 animals lack a PZ, and the remainder have a PZ that is reduced in size, as in the example shown here. Only N2 and aph-2 animals continue to maintain a PZ through adulthood (right). Adult aph-1 gonads lack a PZ and usually contain only oocytes (dashed outline) and spermatids; late-stage pachytene nuclei are sometimes observed, as in the example shown here. All mutant aph animals are M + Z−. Scale bar is 50 µm. b) The number of germ cells in the adult Day 1 PZ was measured in gonads dissected from N2 (left, n = 10; right, n = 17), aph-1(tm4743) (n = 29), aph-2(tm6471) (n = 20) or aph-2(ik7) (n = 17) (left and right experimental conditions differ slightly; see Materials and methods); mean (horizontal line) and SD (vertical line) are indicated. P-values are calculated from A Student's 2-tailed t-test, assuming unequal variances. c) PZ maintenance in aph-2-deficient adult gonads requires glp-1/Notch function. aph-2(tm6471) M + Z− hermaphrodites with glp-1(+) (top) or glp-1(e2144) (bottom) were shifted to restrictive temperature (25°C) after larval germline establishment (L4), and analyzed 48 h later; aph-2(tm6471); glp-1(+) animals maintain undifferentiated germ progenitor/stem cells, while aph-2(tm6471); glp-1(e2144) animals do not, and instead, the gonad contains germ cells in varying stages of meiotic development. A single distal gonad is shown (dashed outline) within the animal; labeling is as in (a).