Nucleic acid-binding protein that promotes Pol IV-dependent small interfering RNA (siRNA) accumulation, DNA methylation and transcriptional silencing. May possess both RNA-directed DNA methylation (RdDM)-dependent and -independent roles in transcriptional silencing. Acts as a pre-mRNA splicing factor that associates with several typical components of the splicing machinery as well as with Pol II. Component of a pre-mRNA splicing complex. Interacts with STA1. Interacts with PRP31 (PubMed:25684655). A number of isoforms are produced. According to EST sequences.