Structure of the differentially expressed mouse U3A gene

Mazan, Sylvie; Gulli, Marie‐Pierre; Joseph, Nicole; Bachellerie, Jean‐Pierre

doi:10.1111/j.1432-1033.1992.tb16871.x

Cited by 15 publications

(15 citation statements)

References 65 publications

(33 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…U3 RNA exhibits a sufficient degree of conservation to allow for a substantial cross-hybridization among distant vertebrates (40), and the same holds true for U14 RNA (56). The conservation observed for U20 RNA sequence between rodents and humans exceeds what is observed for U3 or U14 among the same species.…”

Section: Resultsmentioning

confidence: 79%

U20, a novel small nucleolar RNA, is encoded in an intron of the nucleolin gene in mammals.

Nicoloso¹,

Caizergues‐Ferrer²,

Michot³

et al. 1994

Mol. Cell. Biol.

View full text Add to dashboard Cite

We have found that intron 11 of the nucleolin gene in humans and rodents encodes a previously unidentified small nucleolar RNA, termed U20. The single-copy U20 sequence is located on the same DNA strand as the nucleolin mRNA. U20 RNA, which does not possess a trimethyl cap, appears to result from intronic RNA processing and not from transcription of an independent gene. In mammals, U20 RNA is an 80-nucleotidelong, metabolically stable species, present at about 7 x 103 molecules per exponentially growing HeLa cell. It has a nucleolar localization, as indicated by fluorescence microscopy following in situ hybridization with digoxigenin-labeled oligonucleotides. U20 RNA contains the box C and box D sequence motifs, hallmarks of most small nucleolar RNAs reported to date, and is immunoprecipitated by antifibrillarin antibodies. It also exhibits a 5'-3' terminal stem bracketing the box C-box D motifs like U14, U15, U16, or Y RNA. A U20 homolog of similar size has been detected in all vertebrate classes by Northern (RNA) hybridization with mammalian oligonucleotide probes. U20 RNA contains an extended region (21 nucleotides) of perfect complementarity with a phylogenetically conserved sequence in 18S rRNA. This complementarity is strongly preserved among distant vertebrates, suggesting that U20 RNA may be involved in the formation of the small ribosomal subunit like nucleolin, the product of its host gene.While the function of the abundant nucleoplasmic small nuclear RNAs (snRNAs) Ul, U2, U4/U6, and U5 in premRNA splicing is understood in great detail, our knowledge of the small nucleolar RNAs (snoRNAs), which represent most nonsplicing snRNAs, is much less advanced. Because of the specialization of the nucleolus in ribosome biogenesis, most snoRNAs are assumed to participate in rRNA maturation (16,61). However, direct evidence linking individual snoRNAs to processing of pre-RNA has been obtained for only a limited subset of this class: U3, which is by far the most abundant and has been one of the best studied (7,23,24,26,53), U14 (22, 25, 35, 36, 56), U8 (50), snRlO (60), and snR30 (43). Identification of snoRNA functions faces a major experimental limitation: no cell-free system is yet available that reproduces faithfully the numerous steps of rRNA processing, except for the early cleavage of the primary transcript in mammals, for which an involvement of U3 has been clearly established (26). Moreover, snoRNAs now appear to represent an increasingly complex class. In yeast cells, more than 15 snoRNA species have been identified (15,16,61

show abstract

Section: Resultsmentioning

confidence: 79%

U20, a novel small nucleolar RNA, is encoded in an intron of the nucleolin gene in mammals.

Nicoloso¹,

Caizergues‐Ferrer²,

Michot³

et al. 1994

Mol. Cell. Biol.

View full text Add to dashboard Cite

show abstract

“…Sequence analysis of U3 snoRNA reveals six evolutionarily conserved sequence elements, termed Boxes A, A′, B, C, C′ and D (17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27). Boxes A and A′ are located in the 5′ domain of U3 snoRNA and, along with the 'hinge' region, base pair to sites within the pre-rRNA to direct the multiple endonucleolytic cleavages necessary for the maturation of 18S rRNA (15,16,23,25,28).…”

Section: Introductionmentioning

confidence: 99%

Interaction of the U3-55k protein with U3 snoRNA is mediated by the Box B/C motif of U3 and the WD repeats of U3-55k

Lukowiak

Granneman²,

Mattox

et al. 2000

Nucleic Acids Research

View full text Add to dashboard Cite

U3 small nucleolar RNA (snoRNA) is a member of the Box C/D family of snoRNAs which functions in ribosomal RNA processing. U3-55k is a protein that has been found to interact with U3 but not other members of the Box C/D snoRNA family. We have found that interaction of the U3-55k protein with U3 RNA in vivo is mediated by the conserved Box B/C motif which is unique to U3 snoRNA. Mutation of Box B and Box C, but not of other conserved sequence elements, disrupted interaction of U3-55k with U3 RNA. Furthermore, a fragment of U3 containing only these two conserved elements was bound by U3-55k in vivo. RNA binding assays performed in vitro indicate that Box C may be the primary determinant of the interaction. We have cloned the cDNA encoding the Xenopus laevis U3-55k protein and find strong homology to the human sequence, including six WD repeats. Deletion of WD repeats or sequences near the C-terminus of U3-55k resulted in loss of association with U3 RNA and also loss of localization of U3-55k to the nucleolus, suggesting that protein-protein interactions contribute to the localization and RNA binding of U3-55k in vivo.

show abstract

“…1). Detailed structural studies and functional mapping of U3 RNAs in diverse organisms reveal that many features of U3 RNA structure are conserved (21,23,26,31,35,42,48,49,54,55,58,60). A common two-domain secondary structure exists in which a short 5Ј domain is linked to a larger 3Ј domain via a singlestranded sequence called the hinge region (see Fig.…”

mentioning

confidence: 99%

Nuclear Retention Elements of U3 Small Nucleolar RNA

Speckmann¹,

Narayanan

Terns³

et al. 1999

Molecular and Cellular Biology

View full text Add to dashboard Cite

The processing and methylation of precursor rRNA is mediated by the box C/D small nucleolar RNAs (snoRNAs). These snoRNAs differ from most cellular RNAs in that they are not exported to the cytoplasm. Instead, these RNAs are actively retained in the nucleus where they assemble with proteins into mature small nucleolar ribonucleoprotein particles and are targeted to their intranuclear site of action, the nucleolus. In this study, we have identified the cis-acting sequences responsible for the nuclear retention of U3 box C/D snoRNA by analyzing the nucleocytoplasmic distributions of an extensive panel of U3 RNA variants after injection of the RNAs into Xenopus oocyte nuclei. Our data indicate the importance of two conserved sequence motifs in retaining U3 RNA in the nucleus. The first motif is comprised of the conserved box C and box D sequences that characterize the box C/D family. The second motif contains conserved box sequences B and C. Either motif is sufficient for nuclear retention, but disruption of both motifs leads to mislocalization of the RNAs to the cytoplasm. Variant RNAs that are not retained also lack 5 cap hypermethylation and fail to associate with fibrillarin. Furthermore, our results indicate that nuclear retention of U3 RNA does not simply reflect its nucleolar localization. A fragment of U3 containing the box B/C motif is not localized to nucleoli but retained in coiled bodies. Thus, nuclear retention and nucleolar localization are distinct processes with differing sequence requirements.In all eukaryotic cells, there exist a multitude of RNAs which perform diverse functions at distinct subcellular locations. Since RNAs function at sites in the cell which are remote from where they are synthesized, RNA transport and localization are obligatory steps in gene expression for all eukaryotic cells. Despite the fundamental importance of RNA transport and localization, we have a limited understanding of the cellular mechanisms that ensure that individual RNAs are sorted to the intracellular destinations where they function.We are investigating the mechanisms controlling the intracellular trafficking of small nucleolar RNAs (snoRNAs). snoRNAs consist of a family of more than 150 molecules that are known to function in the processing and modification of rRNA within the nucleolus (2,18,47,68,74). The snoRNAs are categorized almost exclusively into two classes based on sequence homology, secondary structure, function, and binding of common proteins. The two major classes of snoRNAs are known as the box C/D snoRNAs and the box H/ACA snoRNAs (3, 16). In contrast to most other cellular RNAs, newly synthesized snoRNAs are not exported from the nucleus to the cytoplasm (52,71,73). Rather, these RNAs remain in the nucleus and are selectively targeted from their sites of synthesis within the nucleoplasm (17, 69) to their intranuclear site of function, the nucleolus. At least some snoRNAs associate with nucleoplasmic structures known as coiled bodies (5,32,53,61,65). Since the association of snoRNAs with coiled ...

show abstract

Structure of the differentially expressed mouse U3A gene

Cited by 15 publications

References 65 publications

U20, a novel small nucleolar RNA, is encoded in an intron of the nucleolin gene in mammals.

U20, a novel small nucleolar RNA, is encoded in an intron of the nucleolin gene in mammals.

Interaction of the U3-55k protein with U3 snoRNA is mediated by the Box B/C motif of U3 and the WD repeats of U3-55k

Nuclear Retention Elements of U3 Small Nucleolar RNA

Contact Info

Product

Resources

About