owing to the apparent requirement for ISWI in incorporating the linker histone protein H1 (ref. 52), which is in turn required for normal chromosome condensation and compaction53. In females, ISWI deficiency leads to complete sterility8. This results from the misregulation of bone morphogenetic protein (BMP)-mediated gene expression in the germinal stem cells of females, which leads to a rapid loss of self-renewal of these stem cells54. Although the ISWI ATPase is present in three complexes, NURF might be the functionally predominant complex, because deletion of nurf301 (a dedicated component of the NURF complex) recapitulates almost all the phenotypes of the Iswi mutant55.
