Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8322644 | The International Journal of Biochemistry & Cell Biology | 2015 | 13 Pages |
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 22Â bp apart and within 70Â 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.
Keywords
CHART-PCRbHLHIEF2DEElectrophoretic mobility shift assaybasic helix-loop-helixtwo dimensional electrophoresisHumanchromatin immunoprecipitationisoelectric focusingGene regulationB cellsEMSA یا electrophoretic mobility shift assay Transcription factornuclear extractTranscription factorscageMALDI-TOF MSMatrix-assisted laser desorption/ionization time of flight mass spectrometryCHiP
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Authors
Mark N. Cruickshank, James Dods, Rhonda L. Taylor, Mahdad Karimi, Emily J. Fenwick, Elizabeth A. Quail, Alexander J. Rea, V. Michael Holers, Lawrence J. Abraham, Daniela Ulgiati,