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. Author manuscript; available in PMC: 2015 Mar 1.
Published in final edited form as: Biochim Biophys Acta. 2013 Nov 22;1839(3):191–202. doi: 10.1016/j.bbagrm.2013.11.002

Figure 4.

Figure 4

Cohesin recruitment to heterochromatin. Blue double-sided arrows indicate the interactions reported. Pink arrows indicate downstream effects. A. Cohesin and HP1γ require each other to bind to the D4Z4 subtelomeric heterochromatin in a SUV39H-mediated H3K9me3-dependent manner [116]. Direct interaction of NIPBL with HP1 may contribute [116, 156]. The light blue arrow indicates co-recruitment of cohesin and HP1γ to D4Z4 [116]. In addition, an SMC homolog, SMCHD1, binds to D4Z4 [215]. Whether this binding is mediated by HBiX1, an HP1-interacting protein, as observed at the inactive X chromosome [198] is currently unclear. SMCHD1 was shown to be important for the maintenance of DNA methylation [214]. Whether it contributes to DNA hypermethylation at D4Z4 has not been determined. B. Cohesin is recruited to pericentromeric heterochromatin via interaction with histone methyltransferase Suv4-20h2, which mediates H4K20me3. Suv4-20h2 localization is dependent on HP1 bound to methylated H3K9 mediated by SUV39h [157]. The relevance of the NIPBL-HP1 interaction [156] to pericentromeric cohesin recruitment is unclear.