期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2021
卷号：118
期号：28
DOI：10.1073/pnas.2107483118
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：How noncoding transcription influences chromatin states is still unclear. The
Arabidopsis floral repressor gene
FLC is quantitatively regulated through an antisense-mediated chromatin silencing mechanism. The
FLC antisense transcripts form a cotranscriptional R-loop that is dynamically resolved by RNA 3′ processing factors (FCA and FY), and this is linked to chromatin silencing. Here, we investigate this silencing mechanism and show, using single-molecule DNA fiber analysis, that FCA and FY are required for unimpeded replication fork progression across the
Arabidopsis genome. We then employ the chicken DT40 cell line system, developed to investigate sequence-dependent replication and chromatin inheritance, and find that
FLC R-loop sequences have an orientation-dependent ability to stall replication forks. These data suggest a coordination between RNA 3′ processing of antisense RNA and replication fork progression in the inheritance of chromatin silencing at
FLC.
