title: ZBTB20 is a sequence-specific transcriptional repressor of alpha-fetoprotein gene.
abstract: Alpha-fetoprotein (AFP) represents a classical model system to study developmental gene regulation in mammalian cells. We previously reported that liver ZBTB20 is developmentally regulated and plays a central role in AFP postnatal repression. Here we show that ZBTB20 is a sequence-specific transcriptional repressor of AFP. By ELISA-based DNA-protein binding assay and conventional gel shift assay, we successfully identified a ZBTB20-binding site at -104/-86 of mouse AFP gene, flanked by two HNF1 sites and two C/EBP sites in the proximal promoter. Importantly, mutation of the core sequence in this site fully abolished its binding to ZBTB20 in vitro, as well as the repression of AFP promoter activity by ZBTB20. The unique ZBTB20 site was highly conserved in rat and human AFP genes, but absent in albumin genes. These help to explain the autonomous regulation of albumin and AFP genes in the liver after birth. Furthermore, we demonstrated that transcriptional repression of AFP gene by ZBTB20 was liver-specific. ZBTB20 was dispensable for AFP silencing in other tissues outside liver. Our data define a cognate ZBTB20 site in AFP promoter which mediates the postnatal repression of AFP gene in the liver.
authors.affiliation: 1] Department of Pathophysiology, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China [2].
authors.forename: Hai
authors.initials: H
authors.lastname: Zhang
authors.affiliation: 1] Department of Pathophysiology, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China [2].
authors.forename: Dongmei
authors.initials: D
authors.lastname: Cao
authors.affiliation: 1] Department of Pathophysiology, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China [2].
authors.forename: Luting
authors.initials: L
authors.lastname: Zhou
authors.affiliation: Department of Pathophysiology, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Pathophysiology, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China.
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Guo
authors.affiliation: Department of Pathophysiology, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Pathophysiology, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China.
authors.forename: Yuxia
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Microbiology, Immunology &Molecular Genetics, University of Kentucky College of Medicine, 800 Rose Street, Lexington, KY 40536, USA.
authors.forename: Brett T
authors.initials: BT
authors.lastname: Spear
authors.affiliation: MOE Key Laboratory for Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Jia-Wei
authors.initials: JW
authors.lastname: Wu
authors.affiliation: Department of Pathophysiology, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China.
authors.forename: Zhifang
authors.initials: Z
authors.lastname: Xie
authors.affiliation: Department of Pathophysiology, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China.
authors.forename: Weiping J
authors.initials: WJ
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D017930:Genes, Reporter; D056945:Hep G2 Cells; D006801:Humans; D008099:Liver / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D009154:Mutation; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D051381:Rats; D060888:Real-Time Polymerase Chain Reaction; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D000509:alpha-Fetoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D014157:Transcription Factors; C520426:Zbtb20 protein, mouse; D000509:alpha-Fetoproteins; D004247:DNA