RT Journal Article SR Electronic T1 A team of heterochromatin factors collaborates with small RNA pathways to combat repetitive elements and germline stress JF bioRxiv FD Cold Spring Harbor Laboratory SP 112847 DO 10.1101/112847 A1 Alicia N. McMurchy A1 Przemyslaw Stempor A1 Tessa Gaarenstroom A1 Brian Wysolmerski A1 Yan Dong A1 Darya Aussianikava A1 Alex Appert A1 Ni Huang A1 Paulina Kolasinska-Zwierz A1 Alexandra Sapetschnig A1 Eric Miska A1 Julie Ahringer YR 2017 UL http://biorxiv.org/content/early/2017/03/02/112847.abstract AB Repetitive sequences derived from transposons make up a large fraction of eukaryotic genomes and must be silenced to protect genome integrity. Repetitive elements are often found in heterochromatin; however, the roles and interactions of heterochromatin proteins in repeat regulation are poorly understood. Here we show that a diverse set of C. elegans heterochromatin proteins act together with the piRNA and nuclear RNAi pathways to silence repetitive elements and prevent genotoxic stress in the germ line. Mutants in genes encoding HPL-2/HP1, LIN-13, LIN-61, LET-418/Mi-2, and H3K9me2 histone methyltransferase MET-2/SETDB1 also show functionally redundant sterility, increased germline apoptosis, DNA repair defects, and interactions with small RNA pathways. Remarkably, fertility of heterochromatin mutants could be partially restored by inhibiting cep-1/p53, endogenous meiotic double strand breaks, or the expression of MIRAGE1 DNA transposons. Functional redundancy among these factors and pathways underlies the importance of safeguarding the genome through multiple means.