Has a role in the RNA interference (RNAi) pathway which is important for heterochromatin formation and accurate chromosome segregation. A member of the RNA-directed RNA polymerase complex (RDRC) which is involved in the generation of small interfering RNAs (siRNAs) and mediate their association with the RNA-induced transcriptional silencing (RITS) complex. RITS acts as a priming complex for dsRNA synthesis at the site of non-coding centromeric RNA. {ECO:0000269|PubMed:15607976}.