RNA-guided RNA modification: functional organization of the archaeal H/ACA RNP.
In eukaryotes and archaea, uridines in various RNAs are converted to pseudouridines by RNA-guided RNA modification complexes termed H/ACA RNPs. Guide RNAs within the complexes base-pair with target RNAs to direct modification of specific ribonucleotides. Cbf5, a protein component of the complex, likely catalyzes the modification. However, little is known about the organization of H/ACA RNPs and the roles of the multiple proteins thought to comprise the complexes. We have reconstituted functional archaeal H/ACA RNPs from recombinant components, defined the components necessary and sufficient for function, and determined the direct RNA-protein and protein-protein interactions that occur between the components. The results provide substantial insight into the functional organization of this RNP. The functional complex requires a guide RNA and each of four proteins: Cbf5, Gar1, L7Ae, and Nop10. Two proteins interact directly with the guide RNA: L7Ae and Cbf5. L7Ae does not interact with other H/ACA RNP proteins in the absence of the RNA. We have defined two novel functions for Cbf5. Cbf5 is the protein that specifically recognizes and binds H/ACA guide RNAs. In addition, Cbf5 recruits the two other essential proteins, Gar1 and Nop10, to the pseudouridylation guide complex.
Baker
Daniel L
DL
Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602, USA.
Youssef
Osama A
OA
Chastkofsky
Michael I R
MI
Dy
David A
DA
Terns
Rebecca M
RM
Terns
Michael P
MP
D019843:Archaeal Proteins / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D009690:Nucleic Acid Conformation; D011485:Protein Binding / Q000235:genetics / Q000502:physiology; D011560:Pseudouridine / Q000235:genetics / Q000378:metabolism; D020027:Pyrococcus furiosus / Q000235:genetics / Q000502:physiology*; D012323:RNA Processing, Post-Transcriptional / Q000235:genetics / Q000502:physiology*; D019642:RNA, Archaeal / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014529:Uridine / Q000235:genetics / Q000378:metabolism
D019843:Archaeal Proteins; D046912:Multiprotein Complexes; D019642:RNA, Archaeal; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; D011560:Pseudouridine; D014529:Uridine