Glucocorticoid treatment induces programmed cell death (apoptosis) in susceptible T lymphocytes. We have previously isolated and characterized 13 genes induced by agents that cause apoptosis in the murine thymoma cell line, WEHI-7TG. One of these genes, now designated Tcl-30, encodes a 2.4-kb mRNA that is specifically expressed in thymus. Sequence analysis of a full-length cDNA for Tcl-30 reveals a potential open reading frame of 454 amino acids that shares sequence identity to a human placental-specific protein of unknown function, PP11. The putative protein encoded by Tcl-30 also contains a cysteine-rich somatomedin B-like domain found in vitronectin, PP11, and the plasma cell membrane glycoprotein, PC-1. Subpopulations of murine thymocytes sorted on the basis of their expression of the CD4, CD8, and surface heat-stable Ag (HSA) were analyzed by an RNase protection assay to determine the expression of Tcl-30 as a function of T cell development. Tcl-30 was expressed exclusively in the HSA+ T cell populations (CD4-CD8-HSA+; CD4+CD8-HSA+; CD4-CD8+HSA+; and CD4+CD8+HSA+) and not in the HSA-single positive T cell populations (CD4+CD8-or CD4-CD8+) of the thymus or spleen. Therefore, we conclude that Tcl-30 expression is lost during T cell maturation and is absent at the most mature stages of T cell development. The function of Tcl-30 is unknown; however, the CD4+CD8+ double-positive subpopulation expressing Tcl-30 represents thymocytes destined to undergo massive intrathymic cell death. The possibility that Tcl-30 expression may define a population of T lymphocytes that is sensitive to glucocorticoid-mediated apoptosis is discussed.
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Glucocorticoid treatment induces programmed cell death (apoptosis) in susceptible T lymphocytes. We have previously isolated and characterized 13 genes induced by agents that cause apoptosis in the murine thymoma cell line, WEHI-7TG. One of these genes, now designated Tcl-30, encodes a 2.4-kb mRNA that is specifically expressed in thymus. Sequence analysis of a full-length cDNA for Tcl-30 reveals a potential open reading frame of 454 amino acids that shares sequence identity to a human placental-specific protein of unknown function, PP11. The putative protein encoded by Tcl-30 also contains a cysteine-rich somatomedin B-like domain found in vitronectin, PP11, and the plasma cell membrane glycoprotein, PC-1. Subpopulations of murine thymocytes sorted on the basis of their expression of the CD4, CD8, and surface heat-stable Ag (HSA) were analyzed by an RNase protection assay to determine the expression of Tcl-30 as a function of T cell development. Tcl-30 was expressed exclusively in the HSA+ T cell populations (CD4-CD8-HSA+; CD4+CD8-HSA+; CD4-CD8+HSA+; and CD4+CD8+HSA+) and not in the HSA-single positive T cell populations (CD4+CD8-or CD4-CD8+) of the thymus or spleen. Therefore, we conclude that Tcl-30 expression is lost during T cell maturation and is absent at the most mature stages of T cell development. The function of Tcl-30 is unknown; however, the CD4+CD8+ double-positive subpopulation expressing Tcl-30 represents thymocytes destined to undergo massive intrathymic cell death. The possibility that Tcl-30 expression may define a population of T lymphocytes that is sensitive to glucocorticoid-mediated apoptosis is discussed.
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skos:exactMatch | |
uniprot:name |
J. Immunol.
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uniprot:author |
Baughman G.,
Bourgeois S.,
Hyman R.,
Lesley J.,
Trotter J.
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uniprot:date |
1992
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uniprot:pages |
1488-1496
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uniprot:title |
Tcl-30, a new T cell-specific gene expressed in immature glucocorticoid-sensitive thymocytes.
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uniprot:volume |
149
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