Regulation of expression of TL genes of the mouse Mhc.
The expression of thymus leukemia (TL) antigens and genes in thymocytes and activated T cells was examined by immunoprecipitation, flow cytometric, northern, and nuclear run-off transcription analyses. Cell surface forms of TL were detectable by immunoprecipitation on activated peripheral T cells from Tla haplotypes except Tla(b), in agreement with expression observed on thymocytes. Approximately 40%-50% of concanavalin A (Con A) or anti-CD3-activated T cells were TL+, with expression detected on both the CD4 and CD8 subsets by dual-color analysis. Activated T cells expressed detectable levels of TL mRNA 48 h after stimulation, but no TL transcripts were detectable in unstimulated splenocytes. However, TL mRNA expression in mature activated T cells did not precisely mimic thymocyte expression: the level of expression was considerably lower in activated T cells, and in most haplotypes the transcripts produced in activated T cells appeared to represent a subset of the transcripts produced in thymocytes. By run-off transcription assays in isolated nuclei, TL gene expression was detected in activated but not resting T cells indicating that lack of expression of TL in resting T cells is not due to message instability. These data demonstrate that TL genes are inducible and transcriptionally regulated.
Dolby
N
N
Department of Microbiology and Immunology, Baylor College of Medicine, Houston, TX 77030.
Mehta
V
V
Cook
R G
RG
D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D000951:Antigens, Neoplasm / Q000235:genetics*; D015704:CD4 Antigens / Q000032:analysis; D016827:CD8 Antigens; D005786:Gene Expression Regulation; D006183:H-2 Antigens / Q000235:genetics; D015395:Histocompatibility Antigens Class I / Q000235:genetics; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000235:genetics*; D051379:Mice; D008815:Mice, Inbred Strains; D012333:RNA, Messenger / Q000032:analysis; D013601:T-Lymphocytes / Q000276:immunology*; D013950:Thymus Gland / Q000276:immunology*; D014158:Transcription, Genetic
D000945:Antigens, Differentiation, T-Lymphocyte; D000951:Antigens, Neoplasm; D015704:CD4 Antigens; D016827:CD8 Antigens; D006183:H-2 Antigens; D015395:Histocompatibility Antigens Class I; D008562:Membrane Glycoproteins; D012333:RNA, Messenger; C040588:Tla antigens; C028388:thymus-leukemia antigens