title: Overexpression of the antiapoptotic protein A1 promotes the survival of double positive thymocytes awaiting positive selection.
abstract: As it has been shown for Mcl-1, Bcl-xl and Bcl-2, proteins of the Bcl-2 family play a crucial role during T-cell development in the thymus. We here show that the expression of the antiapoptotic gene A1 is specifically enhanced at the DN3/DN4 transition and in DP thymocytes that have been positively selected suggesting that A1 expression might be considered as a transcriptional signature of thymocytes that have received pre-TCR or TCR survival signal. Furthermore, we observed that A1-a overexpression in recombination activation gene 1-deficient mice transgenic for the major histocompatibillity complex class I-restricted F5 TCR enhances cell survival of DP thymocytes and permits accumulation of DP cells awaiting positive selection. However, A1-a overexpression has no effect on negative selection. Therefore, our results suggest that A1 plays a specialized role in allowing survival of DP thymocytes and that its role can be distinguished from that of Mcl-1, Bcl-xl and Bcl-2.
authors.affiliation: Laboratory of homéostasie lymphocytaire, INSERM U503, IFR Biosciences Lyon-Gerland, 21 avenue Tony Garnier, 69007 Lyon, France.
authors.forename: C
authors.initials: C
authors.lastname: Verschelde
authors.forename: D
authors.initials: D
authors.lastname: Michonneau
authors.forename: M-C
authors.initials: MC
authors.lastname: Trescol-Biemont
authors.forename: I
authors.initials: I
authors.lastname: Berberich
authors.forename: A
authors.initials: A
authors.lastname: Schimpl
authors.forename: N
authors.initials: N
authors.lastname: Bonnefoy-Berard
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology; D002470:Cell Survival / Q000502:physiology; D002478:Cells, Cultured; D005434:Flow Cytometry; D015870:Gene Expression; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D015778:Minor Histocompatibility Antigens; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism*; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000166:cytology / Q000378:metabolism*; D013950:Thymus Gland / Q000166:cytology / Q000378:metabolism*; D051020:bcl-X Protein / Q000378:metabolism
chemical_list: C096816:BCL2-related protein A1; C579094:Mcl1 protein, mouse; D015778:Minor Histocompatibility Antigens; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016693:Receptors, Antigen, T-Cell, alpha-beta; D051020:bcl-X Protein