A conserved WD40 protein binds the Cajal body localization signal of scaRNP particles.
Small Cajal body (CB)-specific RNPs (scaRNPs) function in posttranscriptional modification of small nuclear (sn)RNAs. An RNA element, the CAB box, facilitates CB localization of H/ACA scaRNPs. Using a related element in Drosophila C/D scaRNAs, we purified a fly WD40 repeat protein that UV crosslinks to RNA in a C/D CAB box-dependent manner and associates with C/D and mixed domain C/D-H/ACA scaRNAs. Its human homolog, WDR79, associates with C/D, H/ACA, and mixed domain scaRNAs, as well as with telomerase RNA. WDR79's binding to human H/ACA and mixed domain scaRNAs is CAB box dependent, and its association with mixed domain RNAs also requires the ACA motif, arguing for additional interactions of WDR79 with H/ACA core proteins. We demonstrate a requirement for WDR79 binding in the CB localization of a scaRNA. This and other recent reports establish WDR79 as a central player in the localization and processing of nuclear RNPs.
Tycowski
Kazimierz T
KT
Department of Molecular Biophysics and Biochemistry, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06536, USA.
Shu
Mei-Di
MD
Kukoyi
Abiodun
A
Steitz
Joan A
JA
D020816:Amino Acid Motifs; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002846:Chromatography, Affinity; D020541:Coiled Bodies / Q000378:metabolism* / Q000648:ultrastructure; D029721:Drosophila Proteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D016601:RNA-Binding Proteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000032:analysis; D038621:Regulatory Sequences, Ribonucleic Acid; D012261:Ribonucleoproteins / Q000032:analysis / Q000378:metabolism*; D016415:Sequence Alignment
D029721:Drosophila Proteins; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D038621:Regulatory Sequences, Ribonucleic Acid; D012261:Ribonucleoproteins; C541421:WDR79 protein, Drosophila