Characterizing the functional consequences of haploinsufficiency of NELF-A ( WHSC2 ) and SLBP identifies novel cellular phenotypes in Wolf–Hirschhorn syndrome

Author： Kerzendorfer Claudia Hannes Femke Colnaghi Rita Abramowicz Iga Carpenter Gillian Vermeesch Joris Robert O'Driscoll Mark

Publisher： Oxford University Press

ISSN： 1460-2083

Source： Human Molecular Genetics, Vol.21, Iss.10, 2012-05, pp. : 2181-2193

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Abstract

Wolf–Hirschhorn syndrome (WHS) is a contiguous gene deletion disorder associated with the distal part of the short arm of chromosome 4 (4p16.3). Employing a unique panel of patient-derived cell lines with differing-sized 4p deletions, we provide evidence that haploinsufficiency of SLBP and/or WHSC2 (NELF-A) contributes to several novel cellular phenotypes of WHS, including delayed progression from S-phase into M-phase, reduced DNA replication in asynchronous culture and altered higher order chromatin assembly. The latter is evidenced by reduced histone–chromatin association, elevated levels of soluble chaperone-bound histone H3 and increased sensitivity to micrococcal nuclease digestion in WHS patient-derived cells. We also observed increased camptothecin-induced inhibition of DNA replication and hypersensitivity to killing. Our work provides a novel pathogenomic insight into the aetiology of WHS by describing it, for the first time, as a disorder of impaired chromatin reorganization. Delayed cell-cycle progression and impaired DNA replication likely underlie or contribute to microcephaly, pre- and postnatal growth retardation, which constitute the core clinical features of WHS.