Authors:
Taylor RL, Cruickshank MN, Karimi M, Ng HL, Quail E, Kaufman KM, Harley JB, Abraham LJ, Tsao BP, Boackle SA, Ulgiati D.
Authors notes:
Cellular and Molecular Immunology. 2016;13(1):119-31.
Keywords:
Human CR2/CD21, promoter, TATA, mature B cells, CR2/CD21 expression
Abstract:
Complement receptor 2 (CR2/CD21) is predominantly expressed on the surface of mature B cells where it forms part of a coreceptor complex that functions, in part, to modulate B-cell receptor signal strength.
CR2/CD21 expression is tightly regulated throughout B-cell development such that CR2/CD21 cannot be detected on pre-B or terminally differentiated plasma cells. CR2/CD21 expression is upregulated at B-cell maturation and can be induced by IL-4 and CD40 signaling pathways.
We have previously characterized elements in the proximal promoter and first intron of CR2/CD21 that are involved in regulating basal and tissue-specific expression.
We now extend these analyses to the CR2/CD21 core promoter.
We show that in mature B cells, CR2/CD21 transcription proceeds from a focused TSS regulated by a non-consensus TATA box, an initiator element and a downstream promoter element.
Furthermore, occupancy of the general transcriptional machinery in pre-B versus mature B-cell lines correlate with CR2/CD21 expression level and indicate that promoter accessibility must switch from inactive to active during the transitional B-cell window.