The mammalian exosome mediates the efficient degradation of mRNAs that contain AU-rich elements.
HeLa cytoplasmic extracts contain both 3'-5' and 5'-3' exonuclease activities that may play important roles in mRNA decay. Using an in vitro RNA deadenylation/decay assay, mRNA decay intermediates were trapped using phosphothioate-modified RNAs. These data indicate that 3'-5' exonucleolytic decay is the major pathway of RNA degradation following deadenylation in HeLa cytoplasmic extracts. Immunodepletion using antibodies specific for the exosomal protein PM-Scl75 demonstrated that the human exosome complex is required for efficient 3'-5' exonucleolytic decay. Furthermore, 3'-5' exonucleolytic decay was stimulated dramatically by AU-rich instability elements (AREs), implicating a role for the exosome in the regulation of mRNA turnover. Finally, PM-Scl75 protein was found to interact specifically with AREs. These data suggest that the interaction between the exosome and AREs plays a key role in regulating the efficiency of ARE-containing mRNA turnover.
Mukherjee
Devi
D
Department of Microbiology and Molecular Genetics, UMDNJ-New Jersey Medical School, Newark, NJ 07103, USA.
Gao
Min
M
O'Connor
J Patrick
JP
Raijmakers
Reinout
R
Pruijn
Ger
G
Lutz
Carol S
CS
Wilusz
Jeffrey
J
D001482:Base Composition; D001483:Base Sequence; D003593:Cytoplasm / Q000378:metabolism; D043211:Exodeoxyribonuclease V; D005090:Exodeoxyribonucleases / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008954:Models, Biological; D009154:Mutation; D020871:RNA Stability; D012333:RNA, Messenger / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D005090:Exodeoxyribonucleases; D043211:Exodeoxyribonuclease V