title: Perturbation of thymocyte development in nonsense-mediated decay (NMD)-deficient mice.
abstract: The random nature of T-cell receptor-β (TCR-β) recombination needed to generate immunological diversity dictates that two-thirds of alleles will be out-of-frame. Transcripts derived from nonproductive rearrangements are cleared by the nonsense-mediated mRNA decay (NMD) pathway, the process by which cells selectively degrade transcripts harboring premature termination codons. Here, we demonstrate that the fetal thymus in transgenic mice that ubiquitously express a dominant-negative form of Rent1/hUpf1, an essential trans-effector of NMD, shows decreased cell number, reduced CD4CD8 double-positive thymocytes, diminished expression of TCR-β, and increased expression of CD25, suggesting a defect in pre-TCR signaling. Transgenic fetal thymocytes also demonstrated diminished endogenous Vβ-to-DβJβ rearrangements, whereas Dβ-to-Jβ rearrangements were unperturbed, suggesting that inhibition of NMD induces premature shut-off of TCR-β rearrangement. Developmental arrest of thymocytes is prevented by the introduction of a fully rearranged TCR-β transgene that precludes generation of out-of-frame transcripts, suggesting direct mRNA-mediated trans-dominant effects. These data document that NMD has been functionally incorporated into developmental programs during eukaryotic evolution.
authors.affiliation: Department of Pediatrics, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Pamela A
authors.initials: PA
authors.lastname: Frischmeyer-Guerrerio
authors.forename: Robert A
authors.initials: RA
authors.lastname: Montgomery
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Warren
authors.forename: Sara K
authors.initials: SK
authors.lastname: Cooke
authors.forename: Johannes
authors.initials: J
authors.lastname: Lutz
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Sonnenday
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Guerrerio
authors.forename: Harry C
authors.initials: HC
authors.lastname: Dietz
mesh_terms: D000818:Animals; D051379:Mice; D008822:Mice, Transgenic; D012333:RNA, Messenger / Q000378:metabolism*; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology; D013950:Thymus Gland / Q000166:cytology / Q000196:embryology / Q000276:immunology*; D015534:Trans-Activators / Q000235:genetics
chemical_list: D012333:RNA, Messenger; D016693:Receptors, Antigen, T-Cell, alpha-beta; C484446:Rent1 protein, mouse; D015534:Trans-Activators