title: Increased RPA1 gene dosage affects genomic stability potentially contributing to 17p13.3 duplication syndrome.
abstract: A novel microduplication syndrome involving various-sized contiguous duplications in 17p13.3 has recently been described, suggesting that increased copy number of genes in 17p13.3, particularly PAFAH1B1, is associated with clinical features including facial dysmorphism, developmental delay, and autism spectrum disorder. We have previously shown that patient-derived cell lines from individuals with haploinsufficiency of RPA1, a gene within 17p13.3, exhibit an impaired ATR-dependent DNA damage response (DDR). Here, we show that cell lines from patients with duplications specifically incorporating RPA1 exhibit a different although characteristic spectrum of DDR defects including abnormal S phase distribution, attenuated DNA double strand break (DSB)-induced RAD51 chromatin retention, elevated genomic instability, and increased sensitivity to DNA damaging agents. Using controlled conditional over-expression of RPA1 in a human model cell system, we also see attenuated DSB-induced RAD51 chromatin retention. Furthermore, we find that transient over-expression of RPA1 can impact on homologous recombination (HR) pathways following DSB formation, favouring engagement in aberrant forms of recombination and repair. Our data identifies unanticipated defects in the DDR associated with duplications in 17p13.3 in humans involving modest RPA1 over-expression.
authors: Human DNA Damage Response Disorders Group, Genome Damage and Stability Centre, University of Sussex, Brighton, United Kingdom.
authors: Emily
authors: E
authors: Outwin
authors: Gillian
authors: G
authors: Carpenter
authors: Weimin
authors: W
authors: Bi
authors: Marjorie A
authors: MA
authors: Withers
authors: James R
authors: JR
authors: Lupski
authors: Mark
authors: M
authors: O'Driscoll
mesh_terms: D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase / Q000235:genetics / Q000378:metabolism; D000818:Animals; D064007:Ataxia Telangiectasia Mutated Proteins; D016466:CHO Cells; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D058674:Chromosome Duplication / Q000235:genetics*; D002886:Chromosomes, Human, Pair 17 / Q000235:genetics; D006224:Cricetinae; D053903:DNA Breaks, Double-Stranded; D004249:DNA Damage; D018628:Gene Dosage; D015870:Gene Expression; D042822:Genomic Instability; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D009030:Mosaicism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D051135:Rad51 Recombinase / Q000235:genetics / Q000378:metabolism; D051716:Replication Protein A / Q000235:genetics*; D016196:S Phase; D014314:Trisomy / Q000235:genetics*
chemical_list: D018797:Cell Cycle Proteins; D008869:Microtubule-Associated Proteins; C497167:RPA1 protein, human; D051716:Replication Protein A; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases; D051135:Rad51 Recombinase; D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase; C084102:PAFAH1B1 protein, human