Bcl-2 protein is required for the adenine/uridine-rich element (ARE)-dependent degradation of its own messenger.
We have shown previously that the decay of human bcl-2 mRNA is mediated by an adenine/uridine-rich element (ARE) located in the 3'-untranslated region. Here, we have utilized a non-radioactive cell-free mRNA decay system to investigate the biochemical and functional mechanisms regulating the ARE-dependent degradation of bcl-2 mRNA. Using RNA substrates, mutants, and competitors, we found that decay is specific and ARE-dependent, although maximized by the ARE-flanking regions. In unfractionated extracts from different cell types and in whole cells, the relative enzymatic activity was related to the amount of Bcl-2 protein expressed by the cells at steady state. The degradation activity was lost upon Bcl-2 depletion and was reconstituted by adding recombinant Bcl-2. Ineffective extracts from cells that constitutively do not express Bcl-2 acquire full degradation activity by adding recombinant Bcl-2 protein. We conclude that Bcl-2 is necessary to activate the degradation complex on the relevant RNA target.
Bevilacqua
Annamaria
A
Department of Pharmacology, University of Milan, 20129 Milan, Italy.
Ceriani
Maria Cristina
MC
Canti
Gianfranco
G
Asnaghi
Laura
L
Gherzi
Roberto
R
Brewer
Gary
G
Papucci
Laura
L
Schiavone
Nicola
N
Capaccioli
Sergio
S
Nicolin
Angelo
A
D024509:3' Flanking Region / Q000502:physiology*; D000225:Adenine; D001482:Base Composition; D002474:Cell-Free System; D025461:Feedback, Physiological; D006801:Humans; D007700:Kinetics; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics*; D020871:RNA Stability; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D013379:Substrate Specificity; D014407:Tumor Cells, Cultured; D014529:Uridine
D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D000225:Adenine; D014529:Uridine