Nucleic Acids Research, Vol 26, Issue 3 756-760, Copyright © 1998 by Oxford University Press
MR Jacobson and T Pederson
U3 and U8 small nucleolar RNAs (snRNAs) participate in pre-rRNA processing.
Like the U1, U2, U4 and U5 major spliceosomal snRNAs, U3 and U8 RNAs are
transcribed by RNA polymerase II and their initial 7- methylguanosine (m7G)
5' cap structures subsequently become converted to
2,2,7-trimethylguanosine. However, unlike the polymerase II transcribed
spliceosomal snRNAs, which are exported to the cytoplasm for cap
hypermethylation, U3 and U8 RNAs undergo cap hypermethylation within the
nucleus. Human U3 and U8 RNAs with various cap structures were generated by
in vitro transcription, fluorescently labeled and microinjected into nuclei
of normal rat kidney (NRK) epithelial cells. When U3 and U8 RNAs containing
a m7G cap were microinjected they became extensively localized in nucleoli.
U3 and U8 RNAs containing alternative cap structures did not localize in
nucleoli nor did U3 or U8 RNAs containing triphosphate 5'-termini. The
nucleolar localization of m7G-capped U3 RNA was competed by
co-microinjection into the nucleus of a 100-fold molar excess of
dinucleotide m7GpppG but not by a 100- fold excess of ApppG dinucleotide.
Although it was obviously not possible to assess formation of di- and
trimethylguanosine caps on the microinjected U3 and U8 RNAs in these single
cell experiments, these results indicate that the initial presence of a m7G
cap on U3 and U8 RNAs, most likely together with internal sequence
elements, commits these transcripts to the nucleolar localization pathway
and point to diverse roles of the m7G cap in the intracellular traffic of
various RNAs transcribed by RNA polymerase II.
ARTICLES
A 7-methylguanosine cap commits U3 and U8 small nuclear RNAs to the nucleolar localization pathway
Cell Biology Group, Worcester Foundation for Biomedical Research, Shrewsbury, MA 01545, USA.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  N. J. Watkins, I. Lemm, and R. Luhrmann Involvement of Nuclear Import and Export Factors in U8 Box C/D snoRNP Biogenesis Mol. Cell. Biol., October 15, 2007; 27(20): 7018 - 7027. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. J. Watkins, A. Dickmanns, and R. Luhrmann Conserved Stem II of the Box C/D Motif Is Essential for Nucleolar Localization and Is Required, Along with the 15.5K Protein, for the Hierarchical Assembly of the Box C/D snoRNP Mol. Cell. Biol., December 1, 2002; 22(23): 8342 - 8352. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Pederson Fluorescent RNA cytochemistry: tracking gene transcripts in living cells Nucleic Acids Res., March 1, 2001; 29(5): 1013 - 1016. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Prespliceosomal Assembly on Microinjected Precursor mRNA Takes Place in Nuclear Speckles Mol. Biol. Cell, February 1, 2001; 12(2): 393 - 406. [Abstract] [Full Text]
|
|
|
|
|
|
W. A. Speckmann, R. M. Terns, and M. P. Terns The Box C/D motif directs snoRNA 5'-cap hypermethylation Nucleic Acids Res., November 15, 2000; 28(22): 4467 - 4473. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Pederson and J. C. Politz The Nucleolus and the Four Ribonucleoproteins of Translation J. Cell Biol., March 20, 2000; 148(6): 1091 - 1096. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. PEDERSON Movement and localization of RNA in the cell nucleus FASEB J, December 1, 1999; 13(9002): 238S - 242S. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Fortes, J. Kufel, M. Fornerod, M. Polycarpou-Schwarz, D. Lafontaine, D. Tollervey, and I. W. Mattaj Genetic and Physical Interactions Involving the Yeast Nuclear Cap-Binding Complex Mol. Cell. Biol., October 1, 1999; 19(10): 6543 - 6553. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Narayanan, W. Speckmann, R. Terns, and M. P. Terns Role of the Box C/D Motif in Localization of Small Nucleolar RNAs to Coiled Bodies and Nucleoli Mol. Biol. Cell, July 1, 1999; 10(7): 2131 - 2147. [Abstract] [Full Text]
|
|
|
|
|
|
T. S. Lange, M. Ezrokhi, A. V. Borovjagin, R. Rivera-León, M. T. North, and S. A. Gerbi Nucleolar Localization Elements of Xenopus laevis U3 Small Nucleolar RNA Mol. Biol. Cell, October 1, 1998; 9(10): 2973 - 2985. [Abstract] [Full Text]
|
|
|
|
 |
|
 M. R. Jacobson and T. Pederson Localization of signal recognition particle RNA in the nucleolus of mammalian cells PNAS, July 7, 1998; 95(14): 7981 - 7986. [Abstract] [Full Text] [PDF]
|
|