Notch signaling induces a transcriptionally permissive state at the Complement C3d Receptor 2 (CR2) promoter in a pre-B cell model

• Published in: Molecular immunology 2020-12, Vol.128, p.150-164
• Main Authors: Ng, Han Leng, Taylor, Rhonda L., Cheng, Jessica, Abraham, Lawrence J., Quail, Elizabeth, Cruickshank, Mark N., Ulgiati, Daniela
• Format: Article
• Language: English
• Subjects: B cells; B-Lymphocytes - physiology; Cell Differentiation - genetics; Cell Line; Cell Line, Tumor; Chromatin - genetics; Coculture Techniques - methods; Complement; Complement C3d - genetics; Gene regulation; Human; Humans; K562 Cells; Lymphocyte Activation - genetics; Lymphopoiesis - genetics; Molecular biology; Precursor Cells, B-Lymphoid - physiology; Promoter Regions, Genetic - genetics; Receptors, Complement 3d - genetics; Receptors, Notch - genetics; Signal Transduction - genetics; Transcription factors; Transcription, Genetic - genetics
• ISSN: 0161-5890; 1872-9142
• DOI: 10.1016/j.molimm.2020.10.001

•CR2 is uniquely expressed on mature B cells.•Notch signals induce CR2 mRNA expression in human pre-B cell line model.•Following Notch signaling, dynamic chromatin changes observed within CR2 promoter.•Notch signals change CR2 promoter from closed to transcriptionally permissive. During mammalian lymphoid development, Notch signaling is necessary at multiple stages of T lymphopoiesis, including lineage commitment, and later stages of T cell effector differentiation. In contrast, outside of a defined role in the development of splenic marginal zone B cells, there is conflicting evidence regarding whether Notch signaling plays functional roles in other B cell sub-populations. Complement receptor 2 (CR2) modulates BCR-signaling and is tightly regulated throughout differentiation. During B lymphopoiesis, CR2 is detected on immature and mature B cells with high surface expression on marginal zone B cells. Here, we have explored the possibility that Notch regulates human CR2 transcriptional activity using in vitro models including a co-culture system, co-transfection gene reporters and chromatin accessibility assays. We provide evidence that Notch signaling regulates CR2 promoter activity in a mature B cell line, as well as the induction of endogenous CR2 mRNA in a non-expressing pre-B cell line. The dynamics of endogenous gene activation suggests additional unidentified factors are required to mediate surface CR2 expression on immature and mature B lineage cells.