This domain, along with the C-terminal part, Pfam:PF12460 [1], is an essential component of a silencing complex in fission yeast that contains Dos2, Rik1, Mms19 and Cdc20 (the catalytic subunit of DNA polymerase-epsilon). This complex regulates RNA polymerase II (RNA Pol II) activity in heterochromatin and is required for DNA replication and heterochromatin assembly [2].

1: Cloning the human and mouse MMS19 genes and functional complementation of a yeast mms19 deletion mutant. Queimado L, Rao M, Schultz RA, Koonin EV, Aravind L, Nardo T, Stefanini M, Friedberg EC; Nucleic Acids Res. 2001;29:1884-1891. PMID:11328871

2: Coordination of DNA replication and histone modification by the Rik1-Dos2 complex. Li F, Martienssen R, Cande WZ; Nature. 2011;475:244-248. PMID:21725325