Pachytene piRNA Biogenesis Requires MOV10L1 Figure 5. Massive DNA damage in piRNA-deficient round spermatids. (A) Schematic representation of the expression of several proteins involved in chromatin remodeling during mouse spermiogenesis. (B) Phosphorylation of histone H2AX during normal spermatogenesis. Note the presence of cH2AX in three distinct types of germ cells: leptotene/zygotene spermatocytes (due to meiotic recombination), pachytene spermatocytes (XY body only, due to sex chromosome silencing), and elongating spermatids (due to chromatin remodeling). (C) Presence of cH2AX in round spermatids from Mov10l1fl/- Neurog3-Cre testes. (D, E) Double staining of cH2AX and TOP2B in seminiferous tubules from wild-type and Mov10l1fl/- Neurog3-Cre testes. (F, G) Double staining of cH2AX and PRM2 in seminiferous tubules from wild-type and Mov10l1fl/- Neurog3-Cre testes. Red channels and DAPI staining are also shown in separate panels (D–G). Pa, pachytene spermatocytes; RS, round spermatids; ES, elongating spermatids. Scale bar, 25 mm. doi:10.1371/journal.pgen.1003038.g005 PLOS Genetics | www.plosgenetics.org 7 November 2012 | Volume 8 | Issue 11 | e1003038