title: Substrate affinity and substrate specificity of proteasomes with RNase activity.
abstract: 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.
authors.affiliation: ERTAC, Université Blaise Pascal, Clermont-Ferrand II, 24 avenue des Landais, 63177 Aubière, France.
authors.forename: Karine
authors.initials: K
authors.lastname: Gautier-Bert
authors.forename: Bertrand
authors.initials: B
authors.lastname: Murol
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Jarrousse
authors.forename: Lionel
authors.initials: L
authors.lastname: Ballut
authors.forename: Saloua
authors.initials: S
authors.lastname: Badaoui
authors.forename: Frank
authors.initials: F
authors.lastname: Petit
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Schmid
mesh_terms: 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
chemical_list: D009097:Multienzyme Complexes; D012333:RNA, Messenger; D012260:Ribonucleases; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex