RNAi drives nonreciprocal translocations at eroding chromosome ends to establish telomere-free linear chromosomes.

ABSTRACT: The identification of telomerase-negative HAATI (heterochromatin amplification-mediated and telomerase-independent) cells, in which telomeres are superseded by nontelomeric heterochromatin tracts, challenged the idea that canonical telomeres are essential for chromosome linearity and raised crucial questions as to how such tracts translocate to eroding chromosome ends and confer end protection. Here we show that HAATI arises when telomere loss triggers a newly recognized illegitimate translocation pathway that requires RNAi factors. While RNAi is necessary for the translocation events that mobilize ribosomal DNA (rDNA) tracts to all chromosome ends (forming "HAATI^rDNA" chromosomes), it is dispensable for HAATI^rDNA maintenance. Surprisingly, Dicer (Dcr1) plays a separa

SUBMITTER: Begnis M 

PROVIDER: S-EPMC5959237 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature