miR-29b directly targets activation-induced cytidine deaminase in human B cells and can limit its inappropriate expression in naïve B cells
| Autor: | Philip S. Hobson, David J. Cousins, Elizabeth H. Mann, David J. Fear, Timothy Recaldin, Faruk Ramadani, Paul Lavender |
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| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
Immunology Naive B cell Palatine Tonsil Immunoglobulin E Affinity maturation 03 medical and health sciences Cytidine Deaminase medicine Activation-induced (cytidine) deaminase Humans Molecular Biology 3' Untranslated Regions B cell Recombination Genetic B-Lymphocytes biology Base Sequence Genome Human Isotype Immunoglobulin Class Switching Cell biology Enzyme Activation MicroRNAs 030104 developmental biology medicine.anatomical_structure HEK293 Cells Immunoglobulin class switching Gene Knockdown Techniques biology.protein Antibody |
| Zdroj: | Recaldin, T, Hobson, P S, Mann, E H, Ramadani, F, Cousins, D J, Lavender, P & Fear, D J 2018, ' miR-29b directly targets activation-induced cytidine deaminase in human B cells and can limit its inappropriate expression in naïve B cells ', Molecular Immunology, vol. 101, pp. 419-428 . https://doi.org/10.1016/j.molimm.2018.07.028 |
| Popis: | Class-switch recombination (CSR) is an essential B cell process that alters the isotype of antibody produced by the B cell, tailoring the immune response to the nature of the invading pathogen. CSR requires the activity of the mutagenic enzyme AID (encoded by AICDA) to generate chromosomal lesions within the immunoglobulin genes that initiate the class switching recombination event. These AID-mediated mutations also participate in somatic-hypermutation of the immunoglobulin variable region, driving affinity maturation. As such, AID poses a significant oncogenic threat if it functions outside of the immunoglobulin locus. We found that expression of the microRNA, miR-29b, was repressed in B cells isolated from tonsil tissue, relative to circulating naïve B cells. Further investigation revealed that while enforced overexpression of miR-29b in human B cells precipitated a reduction in overall AID protein and a corresponding diminution in CSR to IgE, miR-29b knockdown in naïve B cells resulted in elevated AID expression. Similarly, miR-29b was able to directly interact with the AID 5’-UTR and modulate expression in reporter assays. Given miR-29b’s ability to potently target AID, a mutagenic molecule that can initiate chromosomal translocations and “off-target” mutations, we propose that miR-29b acts to silence premature AID expression in naïve B cells, thus reducing the likelihood of inappropriate and potentially dangerous deamination activity. |
| Databáze: | OpenAIRE |
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