Domain architecture of the PWWP-containing proteins in Monosiga brevicollis . a) the multi-domain protein containing two PWWP (labeled boxes ‘a’ and ‘b’), three PHD, an HMG, AWS and SET-domains has been conserved in the metazoan proteins although the different human copies have lost either the HMG, or the terminal PHD domains (see Figure 6); b) a Peregrin-type protein with the characteristic cassette involving EPL1 (a not well-defined domain), a PHD, Bromo, and PWWP domains. It represents the earliest version and a founding member of the BRPF-family (see Figure 6); c) a Monosiga-specific protein. The PWWP-domain shows low-level similarity with the PWWP domain of animal HDGF proteins; d) a single PWWP domain containing Monosiga-specific protein. Domains are drawn to scale. EPL1 is the Enhancer of polycomb-like domain.