Phospho-mimetic mutations at SYP-5 S541 and SYP-6 T685 cause defects in SC assembly. (A and B) Graph showing the percent viable and male self-progeny from the wild type (n = 1,684) and syp-5^S541Dsyp-6^T685D mutants (n = 1,431) hermaphrodites. ****, P < 0.0001 by unpaired t test. (C) Full-length gonads dissected from wild type and syp-5^S541Dsyp-6^T685D animals were stained for HIM-3 (magenta) and 3xFlag::SYP-5 (green). Composite projection images are shown. Scale bar, 50 µm. (D) Composite immunofluorescence images of dissected gonads from wild type and syp-5^S541Dsyp-6^T685D animals with DNA and phospho-HIM-8/ZIMs (CHK-2 substrate) staining are shown. Yellow dotted lines mark the CHK-2 active zone. Scale bar, 50 µm. (E) Graph showing the CHK-2 active zone in the wild type and syp-5^S541Asyp-6^T685A mutants, shown as a percent gonad length of the pHIM-8/ZIM-positive region relative to the region from meiotic entry to pachytene exit. The numbers of gonads scored are also indicated. **, P = 0.0015 by unpaired t test.