Small RNA profiles of mouse leptotene/zygotene spermatocytes at postnatal day 11 and 16.

Leptotene and zygote (LZ) spematocytes at P11, P16, and P21 were compared by small-RNA-seq. The P21 data has been published under GSE70891. This revealed that, the late piRNA clusters were rarely expressed in P11 LZ spermatocytes, but started to be expressed at P16. Whereas previous reports analysing testicular RNAs showed that "prepachytene" piRNAs are short (25–28 nt) , this study revealed that piRNAs derived from the late piRNA clusters in P16 and P21 LZ spermatocytes contained both short (25–28 nt) and long (29–31 nt) piRNAs. Leptotene and zygote spematocytes were purified by cell sorting using Hochyst staining from testes of male mouse (C57BL/6J) at postnataldays 11 and 16. RNA were extracted by isogene, and used for small RNA library preparation. The libraries were sequenced by MiSeq.