title: Ontogeny of thymic cortical epithelial cells expressing the thymoproteasome subunit β5t.
abstract: Proteasomes are responsible for generating peptides presented by class I MHC molecules of the immune system. β5t, a recently identified proteasome component, is specifically expressed in thymic cortical epithelial cells (cTECs) and plays a pivotal role in generating an immunocompetent repertoire of class I MHC-restricted CD8(+) T cells. Here, we report that β5t is detectable in the thymus as early as E12.5 mouse embryos. We also found that β5t expression in cTECs was detectable in mice deficient for RelB or Rag2, indicating that β5t in cTECs is expressed in the absence of thymic medulla formation or thymocyte development beyond the CD4(-) CD8(-) stage. β5t expression in the embryonic thymus was not detectable in Foxn1-deficient nude mice, although its expression was not reduced in mice deficient for both CCR7 and CCR9, in which fetal thymus colonization by leukocytes is defective. These results indicate that β5t expression in cTECs is dependent on Foxn1 but independent of thymocyte crosstalk or thymic medulla formation.
authors.affiliation: Division of Experimental Immunology, Institute for Genome Research, University of Tokushima, Tokushima, Japan.
authors.forename: Adiratna Mat
authors.initials: AM
authors.lastname: Ripen
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nitta
authors.forename: Shigeo
authors.initials: S
authors.lastname: Murata
authors.forename: Keiji
authors.initials: K
authors.lastname: Tanaka
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Takahama
mesh_terms: D000818:Animals; D018414:CD8-Positive T-Lymphocytes; D002454:Cell Differentiation; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics; D004847:Epithelial Cells / Q000166:cytology / Q000201:enzymology*; D051858:Forkhead Transcription Factors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D015395:Histocompatibility Antigens Class I / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D054504:Precursor Cells, T-Lymphoid / Q000502:physiology; D046988:Proteasome Endopeptidase Complex / Q000235:genetics* / Q000378:metabolism; D054388:Receptors, CCR / Q000172:deficiency / Q000235:genetics; D054400:Receptors, CCR7 / Q000172:deficiency / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013950:Thymus Gland / Q000166:cytology / Q000196:embryology* / Q000201:enzymology; D051841:Transcription Factor RelB / Q000172:deficiency / Q000235:genetics
chemical_list: C119309:CC chemokine receptor 9; C515371:Ccr7 protein, mouse; D004268:DNA-Binding Proteins; D051858:Forkhead Transcription Factors; D015395:Histocompatibility Antigens Class I; C499308:Rag2 protein, mouse; D054388:Receptors, CCR; D054400:Receptors, CCR7; C497594:Relb protein, mouse; C090140:Whn protein; D051841:Transcription Factor RelB; D046988:Proteasome Endopeptidase Complex; C520309:proteasome subunit beta5t, mouse