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The present review summarizes key progress made in characterizing the small nucleolar RNAs (snoRNAs) of eukaryotic cells. Recent studies have shown snoRNA populations to be substantially more complex than anticipated initially. Many newly discovered snoRNAs are synthesized by an intron-processing pathway, which provides a potential mechanism for(More)
HIV-1 entry into CD4(+) cells requires the sequential interactions of the viral envelope glycoproteins with CD4 and a coreceptor such as the chemokine receptors CCR5 and CXCR4. A plausible approach to blocking this process is to use small molecule antagonists of coreceptor function. One such inhibitor has been described for CCR5: the TAK-779 molecule. To(More)
Vertebrate U14 snoRNAs are encoded within hsc70 pre-mRNA introns and U14 biosynthesis occurs via an intron-processing pathway. We have shown previously that essential processing signals are located in the termini of the mature U14 molecule and replacement of included boxes C or D with oligo C disrupts snoRNA synthesis. The experiments detailed here now(More)
Essential elements for intronic U14 processing have been analyzed by microinjecting various mutant hsc70/Ul4 pre-mRNA precursors into Xenopus oocyte nuclei. Initial truncation experiments revealed that elements sufficient for U14 processing are located within the mature snoRNA sequence itself. Subsequent deletions within the U14 coding region demonstrated(More)
Recent investigations have identified homologs of eukaryotic box C/D small nucleolar RNAs (snoRNAs) in Archaea termed sRNAs. Archaeal homologs of the box C/D snoRNP core proteins fibrillarin and Nop56/58 have also been identified but a homolog for the eukaryotic 15.5kD snoRNP protein has not been described. Our sequence analysis of archaeal genomes reveals(More)
The eukaryotic nucleolus contains a diverse population of small nucleolar RNAs (snoRNAs) essential for ribosome biogenesis. The box C/D snoRNA family possesses conserved nucleotide boxes C and D that are multifunctional elements required for snoRNA processing, snoRNA transport to the nucleolus, and 2'-O-methylation of ribosomal RNA. We have previously(More)
We have studied the mechanisms by which the CC-chemokine RANTES can enhance the infectivities of human immunodeficiency virus type 1 (HIV-1) and other enveloped viruses, when present at concentrations in excess of 500 ng/ml in vitro. Understanding the underlying mechanisms might throw light on fundamental processes of viral infection, in particular for(More)
Despite their early discovery, research into the small RNAs associated with the eukaryotic nucleolus (snoRNAs) has lagged behind that of their cousins, the small nuclear RNAs which are known to function in mRNA splicing (spliceosomal snRNAs). Recent progress has now shown that the snoRNAs also occupy a vital niche in the RNA world, participating in the(More)
Incubation of barley aleurone cells with gibberellic acid produces a progressive increase in the RNA content of the cells. The activity of poly(A)-containing RNA, measured in an in vitro wheat germ protein-synthesizing system, reaches a maximum approximately 12 hr after hormone addition and declines thereafter. The structurally intact functional mRNA(More)