title: Structural and functional insights into the human Börjeson-Forssman-Lehmann syndrome-associated protein PHF6.
abstract: The plant homeodomain finger 6 (PHF6) was originally identified as the gene mutated in the X-linked mental retardation disorder Börjeson-Forssman-Lehmann syndrome. Mutations in the PHF6 gene have also been associated with T-cell acute lymphoblastic leukemia and acute myeloid leukemia. Approximately half of the disease-associated mutations are distributed in the second conserved extended plant homeodomain (ePHD2) of PHF6, indicating the functional importance of the ePHD2 domain. Here, we report the high resolution crystal structure of the ePHD2 domain of PHF6, which contains an N-terminal pre-PHD (C2HC zinc finger), a long linker, and an atypical PHD finger. PHF6-ePHD2 appears to fold as a novel integrated structural module. Structural analysis of PHF6-ePHD2 reveals pathological implication of PHF6 gene mutations in Börjeson-Forssman-Lehmann syndrome, T-cell acute lymphoblastic leukemia, and acute myeloid leukemia. The binding experiments show that PHF6-ePHD2 can bind dsDNA but not histones. We also demonstrate PHF6 protein directly interacts with the nucleosome remodeling and deacetylation complex component RBBP4. Via this interaction, PHF6 exerts its transcriptional repression activity. Taken together, these data support the hypothesis that PHF6 may function as a transcriptional repressor using its ePHD domains binding to the promoter region of its repressed gene, and this process was regulated by the nucleosome remodeling and deacetylation complex that was recruited to the genomic target site by NoLS region of PHF6.
authors.affiliation: From the Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China.
authors.forename: Zhonghua
authors.initials: Z
authors.lastname: Liu
authors.forename: Fudong
authors.initials: F
authors.lastname: Li
authors.forename: Ke
authors.initials: K
authors.lastname: Ruan
authors.forename: Jiahai
authors.initials: J
authors.lastname: Zhang
authors.forename: Yide
authors.initials: Y
authors.lastname: Mei
authors.forename: Jihui
authors.initials: J
authors.lastname: Wu
authors.forename: Yunyu
authors.initials: Y
authors.lastname: Shi
mesh_terms: D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004827:Epilepsy / Q000235:genetics / Q000378:metabolism; D005145:Face / Q000002:abnormalities; D005385:Fingers / Q000002:abnormalities; D006130:Growth Disorders / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007006:Hypogonadism / Q000235:genetics / Q000378:metabolism; D015470:Leukemia, Myeloid, Acute / Q000235:genetics / Q000378:metabolism; D038901:X-Linked Intellectual Disability / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D009765:Obesity / Q000235:genetics / Q000378:metabolism; D054218:Precursor T-Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics / Q000378:metabolism; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D012097:Repressor Proteins; D013329:Structure-Activity Relationship
chemical_list: D002352:Carrier Proteins; C502542:PHF6 protein, human; D012097:Repressor Proteins; D004247:DNA
keywords: BFLS; Extended PHD; Genetic Diseases; NuRD; PHF6; Protein Folding; Protein-DNA Interaction; RBBP4; Transcription Regulation; Tumor Suppressor Gene