title: Analysis of tandem E-box motifs within human Complement receptor 2 (CR2/CD21) promoter reveals cell specific roles for RP58, E2A, USF and localized chromatin accessibility.
abstract: Complement receptor 2 (CR2/CD21) plays an important role in the generation of normal B cell immune responses. As transcription appears to be the prime mechanism via which surface CR2/CD21 expression is controlled, understanding transcriptional regulation of this gene will have broader implications to B cell biology. Here we report opposing, cell-context specific control of CR2/CD21 promoter activity by tandem E-box elements, spaced 22 bp apart and within 70 bp of the transcription initiation site. We have identified E2A and USF transcription factors as binding to the distal and proximal E-box sites respectively in CR2-positive B-cells, at a site that is hypersensitive to restriction enzyme digestion compared to non-expressing K562 cells. However, additional unidentified proteins have also been found to bind these functionally important elements. By utilizing a proteomics approach we have identified a repressor protein, RP58, binding the distal E-box motif. Co-transfection experiments using RP58 overexpression constructs demonstrated a specific 10-fold repression of CR2/CD21 transcriptional activity mediated through the distal E-box repressor element. Taken together, our results indicate that repression of the CR2/CD21 promoter can occur through one of the E-box motifs via recruitment of RP58 and other factors to bring about a silenced chromatin context within CR2/CD21 non-expressing cells.
authors: Telethon Kids Institute, 100 Roberts Road, Subiaco, Western Australia, Australia.
authors: Mark N
authors: MN
authors: Cruickshank
authors: Biochemistry and Molecular Biology, School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, Australia.
authors: James
authors: J
authors: Dods
authors: Biochemistry and Molecular Biology, School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, Australia; School of Pathology and Laboratory Medicine, Centre for Genetic Origins of Health and Disease, The University of Western Australia, Australia.
authors: Rhonda L
authors: RL
authors: Taylor
authors: Biochemistry and Molecular Biology, School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, Australia.
authors: Mahdad
authors: M
authors: Karimi
authors: Biochemistry and Molecular Biology, School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, Australia.
authors: Emily J
authors: EJ
authors: Fenwick
authors: Biochemistry and Molecular Biology, School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, Australia.
authors: Elizabeth A
authors: EA
authors: Quail
authors: School of Pathology and Laboratory Medicine, Centre for Genetic Origins of Health and Disease, The University of Western Australia, Australia.
authors: Alexander J
authors: AJ
authors: Rea
authors: Department of Medicine, University of Colorado, School of Medicine, Aurora, CO, United States.
authors: V Michael
authors: VM
authors: Holers
authors: School of Pathology and Laboratory Medicine, Centre for Genetic Origins of Health and Disease, The University of Western Australia, Australia.
authors: Lawrence J
authors: LJ
authors: Abraham
authors: School of Pathology and Laboratory Medicine, Centre for Genetic Origins of Health and Disease, The University of Western Australia, Australia. Electronic address: daniela.ulgiati@uwa.edu.au.
authors: Daniela
authors: D
authors: Ulgiati
mesh_terms: D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins / Q000502:physiology*; D002843:Chromatin / Q000502:physiology; D024721:E-Box Elements; D044127:Epigenesis, Genetic; D006801:Humans; D020014:K562 Cells; D008969:Molecular Sequence Data; D009928:Organ Specificity; D011401:Promoter Regions, Genetic; D017464:Receptors, Complement 3d / Q000235:genetics* / Q000378:metabolism; D012097:Repressor Proteins / Q000502:physiology*; D051720:Upstream Stimulatory Factors / Q000378:metabolism*
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D002843:Chromatin; D017464:Receptors, Complement 3d; D012097:Repressor Proteins; D051720:Upstream Stimulatory Factors; C407909:TCF3 protein, human; C115048:ZBTB18 protein, human
keywords: B cells; Gene regulation; Human; Transcription factors