Substrate affinity and substrate specificity of proteasomes with RNase activity.
We have partially reconstituted 20S proteasome/RNA complexes using oligonucleotides corresponding to ARE (adenosine- and uridine-rich element) (AUUUA)4 and HIV-TAR (human immunodeficiency virus-Tat transactivation response element), a stem-loop structure in the 5' UTR (untranslated region) of HIV-mRNAs. We demonstrate that these RNAs which associate with proteasomes are degraded by proteasomal endonuclease activity. The formation of these 20S proteasome/RNA substrate complexes is rather specific since 20S proteasomes do not interfere with truncated TAR that is not cleaved by proteasomal endonuclease. In addition, affinity of proteasomes for (AUUUA)4 is much stronger as it is for HIV-TAR. These results provide further arguments for our hypothesis that proteasomes could be involved in the destabilisation of cytokines mRNAs containing AUUUA sequences as well as viral mRNAs.
Gautier-Bert
Karine
K
ERTAC, Université Blaise Pascal, Clermont-Ferrand II, 24 avenue des Landais, 63177 Aubière, France.
Murol
Bertrand
B
Jarrousse
Anne-Sophie
AS
Ballut
Lionel
L
Badaoui
Saloua
S
Petit
Frank
F
Schmid
Hans-Peter
HP
D000818:Animals; D002417:Cattle; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D016325:HIV Long Terminal Repeat / Q000502:physiology; D015497:HIV-1 / Q000235:genetics / Q000378:metabolism; D009097:Multienzyme Complexes / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex; D012333:RNA, Messenger / Q000378:metabolism*; D012260:Ribonucleases / Q000378:metabolism*; D013379:Substrate Specificity
D009097:Multienzyme Complexes; D012333:RNA, Messenger; D012260:Ribonucleases; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex