title: Immune proteasomes in the developing rat thymus.
abstract: The age dynamics of the content of the immune proteasome subunits LMP2 and LMP7 in rat thymus during prenatal and early postnatal ontogeny was studied. The LMP2 and LMP7 immune subunits were detected by Western blotting already by the 18th day of embryonic development, their amount increased to the 21st day to the level characteristic of the postnatal state. Double immunofluorescent labeling showed that in the thymus tissue the largest amount of LMP2 and LMP7 is localized in epithelial cells, whereas the level of their expression in thymocytes is lower. The results suggest that the establishment in thymus of selection processes, which depend on activity of immune proteasomes, can take place already in prenatal ontogeny. Analysis of age dynamics of the natural apoptosis level in thymocytes also favors this supposition. The presence of immune proteasomes in thymocytes during perinatal ontogeny suggests that, besides the antigen presentation, immunoproteasomes may possess other important functions.
authors.affiliation: Koltsov Institute of Developmental Biology, Russian Academy of Sciences, Moscow 119991, Russia.
authors.forename: V I
authors.initials: VI
authors.lastname: Melnikova
authors.forename: M A
authors.initials: MA
authors.lastname: Afanasieva
authors.forename: S B
authors.initials: SB
authors.lastname: Dmitrieva
authors.forename: Ya D
authors.initials: YD
authors.lastname: Karpova
authors.forename: N P
authors.initials: NP
authors.lastname: Sharova
authors.forename: L A
authors.initials: LA
authors.lastname: Zakharova
mesh_terms: D000818:Animals; D017209:Apoptosis; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex; D051381:Rats; D017208:Rats, Wistar; D013950:Thymus Gland / Q000196:embryology / Q000201:enzymology* / Q000254:growth & development / Q000276:immunology
chemical_list: D009097:Multienzyme Complexes; C071313:LMP-2 protein; D003546:Cysteine Endopeptidases; C077436:LMP7 protein; D046988:Proteasome Endopeptidase Complex