Molecular cloning of the mouse proteasome subunits MC14 and MECL-1: reciprocally regulated tissue expression of interferon-gamma-modulated proteasome subunits.
The primary structures of the interferon-gamma-inducible mouse 20S proteasome subunit MECL-1 and its alternate homolog MC14 were determined. Northern analysis of mouse tissues revealed that MECL-1 mRNA predominantly occurred in thymus, lymph nodes, and spleen, whereas small amounts were detected in non-lymphoid tissues such as kidney, muscle, and testis. Unexpectedly, probing RNA blots with MC14 showed that tissues with high MECL-1 expression contained little MC14 and vice versa. A very similar reciprocal tissue expression was subsequently found for the homologous subunit pairs LMP2 and delta as well as LMP7 and MB1. The subunit protein composition of 20S proteasomes purified from liver, thymus, and lung reflected RNA expression. The impact of a regulated reciprocal tissue expression is discussed with respect to thymic selection and the induction of tolerance in potentially autoreactive T cells.
Stohwasser
R
R
Institute for Biochemistry, Medical Faculty (Charité), Humboldt University, Berlin, Germany.
Standera
S
S
Peters
I
I
Kloetzel
P M
PM
Groettrup
M
M
D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D003546:Cysteine Endopeptidases / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D007371:Interferon-gamma / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics*; D009928:Organ Specificity / Q000235:genetics; D046988:Proteasome Endopeptidase Complex; D012333:RNA, Messenger / Q000096:biosynthesis
D009097:Multienzyme Complexes; D012333:RNA, Messenger; D007371:Interferon-gamma; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; C490920:Psmb10 protein, mouse