27nt-RNAs guide histone variant deposition via 'RNA-induced DNA replication interference' and thus transmit parental genome partitioning in Stylonychia.

ABSTRACT:

Background

During sexual reproduction in the unicellular ciliate Stylonychia somatic macronuclei differentiate from germline micronuclei. Thereby, programmed sequence reduction takes place, leading to the elimination of > 95% of germline sequences, which priorly adopt heterochromatin structure via H3K27me3. Simultaneously, 27nt-ncRNAs become synthesized from parental transcripts and are bound by the Argonaute protein PIWI1.

Results

These 27nt-ncRNAs cover sequences destined to the developing macronucleus and are thought to protect them from degradation. We provide evidence and propose that RNA/DNA base-pairing guides PIWI1/27nt-RNA complexes to complementary macronucleus-destined DNA target sequences, hence transiently causing locally stalled replication during polytene chro

SUBMITTER: Postberg J 

PROVIDER: S-EPMC5996456 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature