FBS Colloquia No.248Laboratory of Stem Cell Pathology

piRNA biogenesis and silencing by antisense transgene in embryonic male germ cells

IWI-interacting RNAs (piRNAs), germ cell-specific small RNAs, are synthesized from sense and anti-sense RNA containing Transposable Element (TE) sequences for retrotransposon silencing. piRNAs contribute to the methylation of TEs, which is important to spermatogenesis and fertile phenotype. In a previous study, we found that artificial sense and anti-sense RNA can induce a specific gene silencing by mimicking the natural piRNA system in the embryonic germ cells of transgenic mice. In the study, anti-sense Dnmt3L-expressing mice showed the DNMT3L-silencing phenotype with piRNA synthesis against Dnmt3L and spermatogenesis defects. We found the suppressed DNMT3L phenotype was more severe in the Tg mice with a high copy number of the inserted transgene than those with a low one. We would like to discuss that artificial piRNA biosynthesis and piRNA-mediated silencing.