Figure 2.-Dynamic temporal/spatial activation of MPK-1 during oogenesis. Animals of the indicated genotype were grown at 20°, and the gonads were dissected and stained for activated dpMPK-1 (in red) and chromo- some morphology (DAPI in blue). In A-D, distal is to the left and proximal is to the right; germline regions deduced from chromosome morphology (e.g., pachytene) are indicated with the boundaries of the regions, the distal tip and proximal ends of the germline marked by vertical white lines; and panels with com- posite micrographs show a surface view distal to the loop and an interior view at the level of oocyte nuclei proximal to the loop. Dashed red lines indicate elevated dpMPK-1 staining. (A) Wild-type (WT) hermaphrodite germline 24 hr post mid-L4. High dpMPK-1 levels are observed in proximal pachytene and in the -1 through -5 diakinesis oocytes with a low but detectable valley in the loop/diplotene. dpMPK-1 is not detected in the mitotic, transition zone, or distal pachytene regions. (B)
let-60(
ga89gf) hermaphrodite germline 24 hr post mid-L4 at 20°, stained, and photo- graphed together with A; images were processed identically. dpMPK-1 rises earlier in pachytene, remains elevated in the loop/ diplotene, and is further elevated in diakinesis oocytes. dpMPK-1 falls abruptly as the -1 oocyte undergoes maturation in
let-60(
ga89gf) as it does in wild type (Figure 4C). (C)
fog-2(
oz40) female germline 8 hr after synchronization at the L4/adult molt, stained, and photo- graphed together with A and B, but with a 2.53 exposure time, followed by identical im- age processing. dpMPK-1 is observed in prox- imal pachytene as in wild type and a single diakinesis oocyte, -6. Similar results were ob- tained with young
fog-3(
q443) females. (D)
fog-2(
oz40) female germline 20 hr post L4/adult molt containing .15 oocytes arrested in diakinesis (distal-most region not shown).Very low or undetectable dpMPK-1 is observed in proximal pachytene, diplotene, and diakinesis. Not shown is dpMPK-1 accumulation (1) in sheath cell nuclei, which is weak in wild type and elevated in
let-60(
ga89gf), and (2) in a subset of intestinal cells (nucleus and cytoplasm), which is low in wild type and elevated in
let-60(
ga89gf).