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Developmentally regulated, alternative splicing of the Rpn10 gene generates multiple forms of 26S proteasomes
Author(s) -
Kawahara Hiroyuki,
Kasahara Masanori,
Nishiyama Atsuya,
Ohsumi Keita,
Goto Tetsuya,
Kishimoto Takeo,
Saeki Yasushi,
Yokosawa Hideyoshi,
Shimbara Naoki,
Murata Shigeo,
Chiba Tomoki,
Suzuki Koichi,
Tanaka Keiji
Publication year - 2000
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/19.15.4144
Subject(s) - biology , proteasome , alternative splicing , protein subunit , ubiquitin , rna splicing , microbiology and biotechnology , gene , genetics , xenopus , messenger rna , rna
The 26S proteasome is a multisubunit protein‐ destroying machinery that degrades ubiquitin‐tagged proteins. To date only a single species of Rpn10, which possibly functions as a multiubiquitin chain‐binding subunit, has been identified in various organisms. Here we report that mouse Rpn10 mRNAs occur in at least five distinct forms, named Rpn10a to Rpn10e, and that they are generated from a single gene by developmentally regulated, alternative splicing. Rpn10a is ubiquitously expressed, whereas Rpn10e is expressed only in embryos, with the highest levels of expression in the brain. Both forms of Rpn10 are components of the 26S proteasome, with an apparently similar affinity for multiubiquitylated [ 125 I]lysozyme in vitro . However, they exert markedly divergent effects on the destruction of B‐type cyclin in Xenopus egg extracts. Thus, the 26S proteasome occurs in at least two functionally distinct forms: one containing a ubiquitously expressed Rpn10a and the other a newly identified, embryo‐specific Rpn10e. While the former is thought to perform proteolysis constitutively in a wide variety of cells, the latter may play a specialized role in early embryonic development.