“…Prominent among these is the multi-functional Paf1C. Paf1C promotes H2Bub in vivo (Ng et al, 2003a; Wood et al, 2003b; Xiao et al, 2005), and this function is dependent on a small, conserved domain within the Rtf1 subunit, both in yeast (Piro et al, 2012; Warner et al, 2007) and in higher eukaryotes (Cao et al, 2015). This domain, termed the Rtf1 histone modification domain (hereafter, HMD), is required for H2B K123ub in S. cerevisiae (Tomson et al, 2011; Warner et al, 2007), and expression of the HMD is sufficient to restore global H2B K123ub in a yeast strain deleted of the endogenous RTF1 gene (Piro et al, 2012).…”