CHL1 DNA helicase plays a critical role in sister chromatid cohesion []. DDX11 is the mammalian homologue of the yeast CHL1. DDX11 is a DNA helicase involved in cellular proliferation []. In humans a second homologue has been identified, DDX12 []. DDX11 translocates on single-stranded DNA in the 5' to 3' direction in the presence of ATP and, to a lesser extent, dATP. Its unwinding activity requires a 5'-single-stranded region for helicase loading, since flush-ended duplex structures do not support unwinding []. Defects in DDX11 are the cause of Warsaw breakage syndrome (WBRS), a syndrome characterised by severe microcephaly, growth retardation, facial dysmorphism and abnormal skin pigmentation [].
This entry includes a group of ATP-dependent helicases, including Rad3/XPD (ERCC2), Chl1/DDX11, DDX12, RTEL1 and BRIP1. Rad3/XPD is a subunit of RNA polII initiation factor TFIIH and of Nucleotide Excision Repair Factor 3 (NEF3) [, ]. DDX11/Chl1 is required for sister-chromatid cohesion [, , ]. Defects in DDX11 are the cause of Warsaw breakage syndrome (WBRS). It is a syndrome characterised by severe microcephaly, pre- and postnatal growth retardation, facial dysmorphism and abnormal skin pigmentation [].
