Interactome Analysis Reveals a Novel Role for RAD6 in the Regulation of Proteasome Activity and Localization in Response to DNA Damage
MOLECULAR AND CELLULAR BIOLOGY
Authors: An, Hongli; Yang, Lu; Wang, Chen; Gan, Zhixue; Gu, Haihui; Zhang, Tao; Huang, Xin; Liu, Yan; Li, Yufeng; Chang, Shing-Jyh; Lai, Jianghua; Li, Ya-Bin; Chen, Su; Sun, Fang-Lin
Abstract
RAD6, an E2 ubiquitin-conjugating enzyme, is a key node for determining different DNA damage repair pathways, controlling both the error-prone and the error-free DNA damage repair pathways through differential regulation of the ubiquitination of the proliferating cell nuclear antigen (PCNA) protein. However, whether other pathways are involved in the RAD6-mediated regulation of DNA damage repair is still unclear. To deeply understand the molecular mechanisms of RAD6 in DNA damage repair, we performed a proteomic analysis and identified the changes of the protein-protein interaction (PPI) networks of RAD6 before and after X-ray irradiation. Furthermore, our study indicated that a proteasome-related event is likely involved in the DNA damage repair process. Moreover, we found that RAD6 promotes proteasome activity and nuclear translocation by enhancing the degradation of PSMF1 and the lamin B receptor (LBR). Therefore, we provide a novel pathway that is employed by RAD6 in response to DNA damage.
Genome-Wide Association Study of White Blood Cell Count in 16,388 African Americans: the Continental Origins and Genetic Epidemiology Network (COGENT)
PLOS GENETICS
Authors: Reiner, Alexander P.; Lettre, Guillaume; Nalls, Michael A.; Ganesh, Santhi K.; Mathias, Rasika; Austin, Melissa A.; Dean, Eric; Arepalli, Sampath; Britton, Angela; Chen, Zhao; Couper, David; Curb, J. David; Eaton, Charles B.; Fornage, Myriam; Grant, Struan F. A.; Harris, Tamara B.; Hernandez, Dena; Kamatini, Naoyuki; Keating, Brendan J.; Kubo, Michiaki; LaCroix, Andrea; Lange, Leslie A.; Liu, Simin; Lohman, Kurt; Meng, Yan; Mohler, Emile R., III; Musani, Solomon; Nakamura, Yusuke; O'Donnell, Christopher J.; Okada, Yukinori; Palmer, Cameron D.; Papanicolaou, George J.; Patel, Kushang V.; Singleton, Andrew B.; Takahashi, Atsushi; Tang, Hua; Taylor, Herman A., Jr.; Taylor, Kent; Thomson, Cynthia; Yanek, Lisa R.; Yang, Lingyao; Ziv, Elad; Zonderman, Alan B.; Folsom, Aaron R.; Evans, Michele K.; Liu, Yongmei; Becker, Diane M.; Snively, Beverly M.; Wilson, James G.
Abstract
Total white blood cell (WBC) and neutrophil counts are lower among individuals of African descent due to the common African-derived "null" variant of the Duffy Antigen Receptor for Chemokines (DARC) gene. Additional common genetic polymorphisms were recently associated with total WBC and WBC sub-type levels in European and Japanese populations. No additional loci that account for WBC variability have been identified in African Americans. In order to address this, we performed a large genome-wide association study (GWAS) of total WBC and cell subtype counts in 16,388 African-American participants from 7 population-based cohorts available in the Continental Origins and Genetic Epidemiology Network. In addition to the DARC locus on chromosome 1q23, we identified two other regions (chromosomes 4q13 and 16q22) associated with WBC in African Americans (P<2.5 x 10(-8)). The lead SNP (rs9131) on chromosome 4q13 is located in the CXCL2 gene, which encodes a chemotactic cytokine for polymorphonuclear leukocytes. Independent evidence of the novel CXCL2 association with WBC was present in 3,551 Hispanic Americans, 14,767 Japanese, and 19,509 European Americans. The index SNP (rs12149261) on chromosome 16q22 associated with WBC count is located in a large inter-chromosomal segmental duplication encompassing part of the hydrocephalus inducing homolog (HYDIN) gene. We demonstrate that the chromosome 16q22 association finding is most likely due to a genotyping artifact as a consequence of sequence similarity between duplicated regions on chromosomes 16q22 and 1q21. Among the WBC loci recently identified in European or Japanese populations, replication was observed in our African-American meta-analysis for rs445 of CDK6 on chromosome 7q21 and rs4065321 of PSMD3-CSF3 region on chromosome 17q21. In summary, the CXCL2, CDK6, and PSMD3-CSF3 regions are associated with WBC count in African American and other populations. We also demonstrate that large inter-chromosomal duplications can result in false positive associations in GWAS.