Piwi RNAs

PIWI-interacting RNAs (piRNAs) are small non-coding RNAs with essential roles in germ line development through silencing of transposable elements and in regulation of protein-coding genes. Recent studies have deepened our understanding of the biogenesis and function of piRNAs and their roles in infertility, cancer and neurological diseases in humans.

Phase separated, membrane-less germ granules preserve fertility and cellular function in animal germ cells. Here the authors show that loss of germ granules impacts piRNA pathway fidelity in the recognition of self and non-self nucleic acids.

Piwi-interacting RNAs are small RNAs produced by processing of long precursor transcripts. Here the authors report that precursor cleavage typically occurs at positions corresponding to stop codons and that this pattern is conserved across mammals.

Siwi-piRISC protects the germline genome from DNA damage caused by selfish movement of transposons by suppressing their expression. Here, the authors show how molecularly Papi, which plays an important role in the production of Siwi-piRISC, cooperates with Par-1 kinase to ensure the accumulation of Siwi-piRISC in germ cells.

Here, the authors provide mechanistic evidence for the piRNA pathway connection to the heterochromatin machinery in Drosophila.

Mallick et al. investigate the role of the piRNA, piR-39980, and doxorubicin (DOX) resistance in fibrosarcoma, finding that piR-39980 is less expressed in DOX-resistant HT1080 fibrosarcoma cells. The authors reported that its inhibition lead to attenuated intracellular DOX accumulation, DOX-indued apoptosis and anti-proliferative effects in parental HT1080 cells, as well as DNA damage by regulating RRM2 and CYP1A2.