Regulation of A1/Bfl-1 expression in peripheral splenic B cells.
We analyzed here the expression of the prosurvival Bcl-2 homologue A1 in peripheral B cell compartment. We observed that A1 mRNA are highly expressed in peripheral B cells as compared with other anti-apoptotic genes of the Bcl-2 family such as bcl-xl and bcl-2 itself. The expression of A1 is up-regulated in immature B cells at the transition between transitional type 1 (T1) and type 2 (T2) cells, and remained highly expressed in mature (M) B cells. We, therefore, analyzed the effect of B cell antigen receptor (BCR) and BAFF receptor (BAFF-R) engagement on the regulation of A1 in total B220(+) cells but also FACS-sorted immature T1, T2 and M B cells. We demonstrated that only BCR engagement up-regulated the expression of A1 mRNA and protein. These results suggest that A1 may play a key role in antigen-dependent signals that are required for survival and/or proliferation of peripheral B cells.
Trescol-Biémont
Marie-Claude
MC
Inserm U503, IFR128 Bioscience Lyon-Gerland, Centre d'Etude et de Recherche en Virologie et Immunologie, 21, avenue Tony Garnier, 69365 Lyon cedex 7, France.
Verschelde
Claire
C
Cottalorda
Anne
A
Bonnefoy-Bérard
Nathalie
N
D000818:Animals; D017209:Apoptosis; D053265:B-Cell Activation Factor Receptor; D001402:B-Lymphocytes / Q000378:metabolism*; D005786:Gene Expression Regulation; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D015778:Minor Histocompatibility Antigens; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger; D011947:Receptors, Antigen, B-Cell / Q000235:genetics / Q000378:metabolism; D018124:Receptors, Tumor Necrosis Factor / Q000235:genetics / Q000378:metabolism; D013154:Spleen / Q000166:cytology*; D013601:T-Lymphocytes / Q000378:metabolism; D018417:Th1 Cells / Q000378:metabolism; D018418:Th2 Cells / Q000378:metabolism; D051020:bcl-X Protein
D053265:B-Cell Activation Factor Receptor; C096816:BCL2-related protein A1; C494812:Bcl2l1 protein, mouse; D008565:Membrane Proteins; D015778:Minor Histocompatibility Antigens; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D011947:Receptors, Antigen, B-Cell; D018124:Receptors, Tumor Necrosis Factor; C486662:Tnfrsf13c protein, mouse; D051020:bcl-X Protein