MIWI catalysis is required for piRNA amplification-independent LINE1 transposon silencing [microarray]

Here we show that MIWI is a small RNA-guided ribonuclease (Slicer) that requires extensive complementarity for target cleavage in vitro. Disruption of its catalytic activity in mice by a single point mutation results in male infertility and displays increased accumulation of LINE1 transposon transcripts. Round spermatids were purified from adult mouse testes of indicated Miwi genotypes. Total RNA was extracted and subjected to microarray analysis for gene expression profiling.