title: Characterization of the transcriptional expression of Notch-1 signaling pathway members, Deltex and HES-1, in developing mouse thymocytes.
abstract: The Notch transmembrane protein is involved in a broad range of different developmental pathways in vertebrates and invertebrates. Targeted thymocyte expression of the Notch-1 intracellular domain has been shown to affect lineage commitment decisions such as those involving T cell vs. B cell, thymocyte alpha beta vs. gamma delta TCR, as well as CD4 vs. CD8 thymocyte commitment. In this paper, we quantitatively characterize thymocyte RNA expression of two purported transcriptional markers of Notch-1 signaling activity, Deltex and HES-1. Using a semiquantitative RTPCR approach, we show that both Deltex and HES-1 transcriptional levels are developmentally regulated as thymocytes mature from the earliest CD4/CD8 double negative thymocyte stage, through the intermediate CD4/CD8 double positive stage, and finally to the mature CD4 or CD8 single positive stage. Deltex and HES-1, despite both being transcriptional markers of Notch-1 activity, express different patterns of transcriptional activity among the thymocyte subsets. Neither treatment with combined (alpha CD3)/(alpha CD28) antibodies nor the combination of the phorbol ester PMA and calcium ionophore ionomycin affects expression of Deltex in immature thymocytes; however, PMA/ionomycin treatment does downregulate expression of HES-1, an affect mostly mediated by ionomycin. Finally, a difference in HES-1 expression is seen between CD4/CD8 double positive thymocytes isolated from wild-type vs. MHC class I/II deficient mice, suggesting that Notch-1 activity is modulated during in vivo TCR/MHC-ligand selection events.
authors.affiliation: Department of Pathology, Kaplan Comprehensive Cancer Center, New York University Medical Center, New York, NY 10016, USA.
authors.forename: Jung W
authors.initials: JW
authors.lastname: Choi
authors.forename: Christine
authors.initials: C
authors.lastname: Pampeno
authors.forename: Stanislav
authors.initials: S
authors.lastname: Vukmanovic
authors.forename: Daniel
authors.initials: D
authors.lastname: Meruelo
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000276:immunology; D051792:Basic Helix-Loop-Helix Proteins; D002352:Carrier Proteins; D018507:Gene Expression Regulation, Developmental / Q000276:immunology; D005805:Genes, MHC Class I / Q000276:immunology; D005802:Genes, MHC Class II / Q000276:immunology; D018398:Homeodomain Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D015759:Ionomycin / Q000276:immunology; D007476:Ionophores / Q000276:immunology; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics / Q000276:immunology*; D012313:RNA / Q000737:chemistry / Q000235:genetics; D051881:Receptor, Notch1; D011956:Receptors, Cell Surface; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013755:Tetradecanoylphorbol Acetate / Q000276:immunology; D013950:Thymus Gland / Q000254:growth & development / Q000276:immunology* / Q000378:metabolism; D000072056:Transcription Factor HES-1; D014157:Transcription Factors; D014158:Transcription, Genetic / Q000235:genetics / Q000276:immunology
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D002352:Carrier Proteins; D018398:Homeodomain Proteins; D015759:Ionomycin; D007476:Ionophores; D008565:Membrane Proteins; D011506:Proteins; D012313:RNA; D051881:Receptor, Notch1; D011956:Receptors, Cell Surface; D013755:Tetradecanoylphorbol Acetate; D000072056:Transcription Factor HES-1; D014157:Transcription Factors; C489734:Hes1 protein, mouse; C497762:Notch1 protein, mouse; C409218:deltex protein, vertebrate