Dosage Effects of Cohesin Regulatory Factor PDS5 on Mammalian Development: Implications for Cohesinopathies

et al. (2009) Dosage Effects of Cohesin Regulatory Factor PDS5 on Mammalian Development: Implications for Cohesinopathies. PLoS ONE 4(5): e5232. doi:10.1371/journal.pone.0005232 Dosage Effects of Cohesin Regulatory Factor PDS5 on Mammalian Development: Implications for Cohesinopathies Bin Zhang 0 Jufang Chang 0 Ming Fu 0 Jie Huang 0 Rakesh Kashyap 0 Ezequiel Salavaggione 0 Sanjay 0 Jain 0 Kulkarni Shashikant 0 Matthew A. Deardorff 0 Maria L. Giovannucci Uzielli 0 Dale Dorsett 0 David C. Beebe 0 Patrick Y. Jay 0 Robert O. Heuckeroth 0 Ian Krantz 0 Jeffrey Milbrandt 0 Ellen A. A. Nollen, University Medical Center Groningen, Netherlands 0 1 Department of Pathology and Immunology, Washington University School of Medicine, St Louis, Missouri, United States of America, 2 Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri, United States of America, 3 Department of Developmental Biology, Washington University School of Medicine, St Louis, Missouri, United States of America, 4 Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St Louis, Missouri, United States of America, 5 Department of Genetics, Washington University School of Medicine, St Louis, Missouri, United States of America, 6 Department of Medicine (Renal Division), Washington University School of Medicine, St Louis, Missouri, United States of America, 7 HOPE Center for Neurological Disorders, Washington University School of Medicine, St Louis, Missouri, United States of America, 8 Division of Human and Molecular Genetics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America, 9 Department of Pediatrics, University of Florence , Firenze , Italy , 10 Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine , Saint Louis, Missouri , United States of America Cornelia de Lange syndrome (CdLS), a disorder caused by mutations in cohesion proteins, is characterized by multisystem developmental abnormalities. PDS5, a cohesion protein, is important for proper chromosome segregation in lower organisms and has two homologues in vertebrates (PDS5A and PDS5B). Pds5B mutant mice have developmental abnormalities resembling CdLS; however the role of Pds5A in mammals and the association of PDS5 proteins with CdLS are unknown. To delineate genetic interactions between Pds5A and Pds5B and explore mechanisms underlying phenotypic variability, we generated Pds5A-deficient mice. Curiously, these mice exhibit multiple abnormalities that were previously observed in Pds5B-deficient mice, including cleft palate, skeletal patterning defects, growth retardation, congenital heart defects and delayed migration of enteric neuron precursors. They also frequently display renal agenesis, an abnormality not observed in Pds5B2/2 mice. While Pds5A2/2 and Pds5B2/2 mice die at birth, embryos harboring 3 mutant Pds5 alleles die between E11.5 and E12.5 most likely of heart failure, indicating that total Pds5 gene dosage is critical for normal development. In addition, characterization of these compound homozygous-heterozygous mice revealed a severe abnormality in lens formation that does not occur in either Pds5A2/2 or Pds5B2/2 mice. We further identified a functional missense mutation (R1292Q) in the PDS5B DNA-binding domain in a familial case of CdLS, in which affected individuals also develop megacolon. This study shows that PDS5A and PDS5B functions other than those involving chromosomal dynamics are important for normal development, highlights the sensitivity of key developmental processes on PDS5 signaling, and provides mechanistic insights into how PDS5 mutations may lead to CdLS. - Funding: This work was supported by NIH Neuroscience Blueprint Center Core Grant P30 NS057105 to Washington University, the HOPE Center for Neurological Disorders, and NIH grants CA111966 and AG13730 (J.M.), HD047396 (S.J.), DK57038 and DK6459201 (R.O.H.), EY04853 (D.C.B.), and Washington University Cancer Biology Pathway Fellowship (B.Z.). P.Y.J. is a Scholar of the Child Health Research Center of Excellence in Developmental Biology at Washington University School of Medicine (HD001487). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. Cornelia de Lange syndrome (CdLS; OMIM #122470) is a rare developmental disorder (,1:10,000) characterized by mental retardation, myopia, growth retardation, congenital heart defects, intestinal anomalies, facial dysmorphisms including cleft palate and appendicular skeletal malformations [1]. A breakthrough in the understanding of CdLS occurred when mutations in the NIPBL gene were identified in ,50% of CdLS patients [2,3]. NIPBL protein is required for cohesin, a protein complex that mediates sister chromatid cohesion, to bind to chromosomes. More recently, mutations in SMC1A and SMC3, core components of cohesin, have been identified in CdLS patients [4], indicating that cohesin dysfunction is the basis of the anomalies associated with CdLS. In addition, mutations in ESCO2, a protein acetyltransferase required for sister chromatid cohesion, have been identified in Roberts syndrome (RBS; OMIM # 268300), a developmental disorder with similarities to CdLS [5,6]. Most CdLS cases are sporadic (.99%), but some show an autosomal dominant [2,7] or X-linked recessive pattern of inheritance with variable expressivity or incomplete penetrance [8]. Interestingly, the abnormalities of affected individuals that share the same mutation even within families can vary widely [811]. The mechanistic basis of variability in phenotypic expressivity and penetrance in CdLS are unknown but are thought to involve modifier genes, epigenetic factors or environmental influences [12]. Cohesin is a highly conserved multi-protein complex required for sister chromatid cohesion, a process that ensures accurate chromosomal segregation during cell division. The cohesin complex consists of the core components, SMC1, SMC3, SCC1(RAD21) and SCC3 (SA), and is regulated by the associated factors, PDS5 (PDS5A and PDS5B in mammals), WAPL, SCC2 (NIPBL), SCC4 (MAU-2), ECO1 (ESCO1 and ESCO2 in mammals) and Separase [1317]. In addition to chromosomal dynamics, cohesin and its regulatory factors play important roles in development by regulating cell movement and axonal outgrowth in C. elegans [18,19], transcriptional regulation of neurodevelopmental regulators in Zebrafish [20], and control of long-range gene expression in Drosophila [21]. Most recently, the non-mitotic functions of cohesin and cohesin-associated proteins have been highlighted by their high expression in post-mitotic neurons in adult mice [22,23], the neuronal deficits in Pds5Bdeficient mice [22], and the discovery that Drosophila mutants in SMC1, RAD21, and SA have defects in axonal pruning a (...truncated)