Human 1A6/DRIM, the homolog of yeast Utp20, functions in the 18S rRNA processing.
1A6/DRIM is a nucleolar protein with a nucleolar targeting sequence in its 3'-terminus. Bioinformatic analysis indicated that human 1A6/DRIM shares 23% identity and 43% similarity with yeast Utp20, which has been reported as a component of U3 snoRNA protein complex and has been implicated in 18S rRNA processing. In the present study, we found, by utilizing RT-PCR with RNA extracted from anti-1A6/DRIM immunoprecipitates and Northern blotting, that 1A6/DRIM is associated with U3 snoRNA. Pulse-chase labeling assays showed that silencing of 1A6/DRIM expression in HeLa cells resulted in a delayed 18S rRNA processing. Furthermore, immunoprecipitations revealed that 1A6/DRIM was also associated with fibrillarin, another U3 RNP component in HeLa cells. These results indicate that 1A6/DRIM is involved in 18S rRNA processing and is the bona fide mammalian Utp20.
Wang
You
Y
Beijing Institute for Cancer Research, School of Oncology, Peking University, 52 Fucheng Road, Beijing 100036, China.
Liu
Jiangying
J
Zhao
Hong
H
Lü
Wenqing
W
Zhao
Jun
J
Yang
Lin
L
Li
Ning
N
Du
Xiaojuan
X
Ke
Yang
Y
D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism; D020868:Gene Silencing; D006367:HeLa Cells; D006801:Humans; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional / Q000502:physiology*; D012337:RNA, Ribosomal, 18S / Q000378:metabolism*; D020537:RNA, Small Nucleolar / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics; D017386:Sequence Homology, Amino Acid
D002868:Chromosomal Proteins, Non-Histone; D009687:Nuclear Proteins; D012337:RNA, Ribosomal, 18S; D020537:RNA, Small Nucleolar; C117378:RNA, U3 small nucleolar; D012261:Ribonucleoproteins; D029701:Saccharomyces cerevisiae Proteins; C113527:UTP20 protein, human; C047458:fibrillarin