News Finding: By bridging the S1 and S2 compartments, SMCHD1 was found to induce their merging into the conformation that prevents gene expression.
Paper Finding: Thus, whereas Xist RNA fuses A/B into S1/S2 compartments, SMCHD1 merges S1/S2 ( Figure 7D ).
News Context: They then found that the loss of SMCHD1 prevented the spreading of Xist across the chromosome and kept the two large domains, which the team named S1 and S2 compartments, from being merged into the typical compartment-less inactive X structure. By bridging the S1 and S2 compartments, SMCHD1 was found to induce their merging into the conformation that prevents gene expression. She says, "The knowledge gained could also be used to reactivate the inactive X chromosome to treat certain diseases, such as the neurodevelopmental disorders Rett syndrome and CDKL5 disorder.
Paper Context: SMCHD1 binds and bridges S1 and S2 compartments to create the ''compartment-less'' state ( Figures 4 and 7D ). Thus, whereas Xist RNA fuses A/B into S1/S2 compartments, SMCHD1 merges S1/S2 ( Figure 7D ). Failure to merge S1/S2 compartments is functionally significant, as regional Xist spreading becomes compromised ( Figure 3 ) and $43% of genes normally subject to XCI cannot be properly heterochromatinized or silenced (Figures 1 and 2 ).