RNA quality control by CCR4 safeguards chromatin integrity and centromere function in Arabidopsis

The centromere is a pivotal chromatin domain that ensures accurate chromosome segregation during cell division. However, the epigenome regulation of the centromere and its impact on centromere function remain largely elusive. Here in the model plant Arabidopsis, we show that CCR4, the catalytic subunit of the RNA deadenylation complex CCR4-NOT, is essential for maintenance of the centromere epigenome and chromosome integrity. We demonstrate that CCR4 is involved in shortening of the poly(A) tails of transcripts originated from centromeric transposons and repeats, thereby promoting the production of small interfering RNAs (siRNAs). The CCR4-dependent siRNAs guide non-CG DNA methylation at centromere repeats, and CCR4 cooperates with canonical DNA methylation pathways to enhance centromeric H3K9 methylation and ensure mitotic chromosome stability. Our study illustrates the crucial role of RNA quality control in RNA interference and reveals the elaborate mechanism that safeguards plant centromeres through epigenomic regulation.