scholarly journals Highly Similar Morphologies Between Chromosomes Bearing U2 snRNA Gene Clusters in the Group Astyanax Baird and Girard, 1854 (Characiformes, Characidae): An Evolutionary Approach in Species with 2n = 36, 46, 48, and 50

Zebrafish ◽  
2016 ◽  
Vol 13 (6) ◽  
pp. 565-570 ◽  
Author(s):  
Diovani Piscor ◽  
Liano Centofante ◽  
Patricia Pasquali Parise-Maltempi
Keyword(s):  
Gene Clusters ◽  
Evolutionary Approach ◽  
U2 Snrna ◽  
Snrna Gene

An mRNA-type intron is present in the Rhodotorula hasegawae U2 small nuclear RNA gene

1993 ◽  
Vol 13 (9) ◽  
pp. 5613-5619
Author(s):  
Y Takahashi ◽  
S Urushiyama ◽  
T Tani ◽  
Y Ohshima
Keyword(s):  
Mrna Splicing ◽  
Small Nuclear Rna ◽  
U2 Snrna ◽  
U6 Snrna ◽  
Branch Site ◽  
Snrna Gene ◽  
Nuclear Rna ◽  
Catalytic Role ◽  
Mrna Precursor ◽  
Site Recognition

Splicing an mRNA precursor requires multiple factors involving five small nuclear RNA (snRNA) species called U1, U2, U4, U5, and U6. The presence of mRNA-type introns in the U6 snRNA genes of some yeasts led to the hypothesis that U6 snRNA may play a catalytic role in pre-mRNA splicing and that the U6 introns occurred through reverse splicing of an intron from an mRNA precursor into a catalytic site of U6 snRNA. We characterized the U2 snRNA gene of the yeast Rhodotorula hasegawae, which has four mRNA-type introns in the U6 snRNA gene, and found an mRNA-type intron of 60 bp. The intron of the U2 snRNA gene is present in the highly conserved region immediately downstream of the branch site recognition domain. Interestingly, we found that this region can form a novel base pairing with U6 snRNA. We discuss the possible implications of these findings for the mechanisms of intron acquisition and for the role of U2 snRNA in pre-mRNA splicing.

scholarly journals Interactions of U2 Gene Loci and Their Nuclear Transcripts with Cajal (Coiled) Bodies: Evidence for PreU2 within Cajal Bodies

2000 ◽  
Vol 11 (9) ◽  
pp. 2987-2998 ◽  
Author(s):  
Kelly P. Smith ◽  
Jeanne Bentley Lawrence
Keyword(s):  
Potential Role ◽  
Coiled Body ◽  
Oligonucleotide Probes ◽  
Primary Transcript ◽  
U2 Snrna ◽  
Rna Foci ◽  
Coiled Bodies ◽  
Snrna Gene

The Cajal (coiled) body (CB) is a structure enriched in proteins involved in mRNA, rRNA, and snRNA metabolism. CBs have been shown to interact with specific histone and snRNA gene loci. To examine the potential role of CBs in U2 snRNA metabolism, we used a variety of genomic and oligonucleotide probes to visualize in situ newly synthesized U2 snRNA relative to U2 loci and CBs. Results demonstrate that long spacer sequences between U2 coding repeats are transcribed, supporting other recent evidence that U2 transcription proceeds past the 3′ box. The presence of bright foci of this U2 locus RNA differed between alleles within the same nucleus; however, this did not correlate with the loci's association with a CB. Experiments with specific oligonucleotide probes revealed signal for preU2 RNA within CBs. PreU2 was also detected in the locus-associated RNA foci, whereas sequences 3′ of preU2 were found only in these foci, not in CBs. This suggests that a longer primary transcript is processed before entry into CBs. Although this work shows that direct contact of a U2 locus with a CB is not simply correlated with RNA at that locus, it provides the first evidence of new preU2 transcripts within CBs. We also show that, in contrast to CBs, SMN gems do not associate with U2 gene loci and do not contain preU2. Because other evidence indicates that preU2 is processed in the cytoplasm before assembly into snRNPs, results point to an involvement of CBs in modification or transport of preU2 RNA.

scholarly journals Mutation of a U2 snRNA Gene Causes Global Disruption of Alternative Splicing and Neurodegeneration

Cell ◽  
2012 ◽  
Vol 148 (1-2) ◽  
pp. 296-308 ◽  
Author(s):  
Yichang Jia ◽  
John C. Mu ◽  
Susan L. Ackerman
Keyword(s):  
Alternative Splicing ◽  
U2 Snrna ◽  
Snrna Gene

scholarly journals An mRNA-type intron is present in the Rhodotorula hasegawae U2 small nuclear RNA gene.

1993 ◽  
Vol 13 (9) ◽  
pp. 5613-5619 ◽  
Author(s):  
Y Takahashi ◽  
S Urushiyama ◽  
T Tani ◽  
Y Ohshima
Keyword(s):  
Mrna Splicing ◽  
Small Nuclear Rna ◽  
U2 Snrna ◽  
U6 Snrna ◽  
Branch Site ◽  
Snrna Gene ◽  
Nuclear Rna ◽  
Catalytic Role ◽  
Mrna Precursor ◽  
Site Recognition

Splicing an mRNA precursor requires multiple factors involving five small nuclear RNA (snRNA) species called U1, U2, U4, U5, and U6. The presence of mRNA-type introns in the U6 snRNA genes of some yeasts led to the hypothesis that U6 snRNA may play a catalytic role in pre-mRNA splicing and that the U6 introns occurred through reverse splicing of an intron from an mRNA precursor into a catalytic site of U6 snRNA. We characterized the U2 snRNA gene of the yeast Rhodotorula hasegawae, which has four mRNA-type introns in the U6 snRNA gene, and found an mRNA-type intron of 60 bp. The intron of the U2 snRNA gene is present in the highly conserved region immediately downstream of the branch site recognition domain. Interestingly, we found that this region can form a novel base pairing with U6 snRNA. We discuss the possible implications of these findings for the mechanisms of intron acquisition and for the role of U2 snRNA in pre-mRNA splicing.

scholarly journals RNA-mediated interaction of Cajal bodies and U2 snRNA genes

2001 ◽  
Vol 154 (3) ◽  
pp. 499-510 ◽  
Author(s):  
Mark R. Frey ◽  
A. Gregory Matera
Keyword(s):  
Nuclear Export ◽  
Marked Decrease ◽  
Gene Clusters ◽  
Cajal Bodies ◽  
U2 Snrna ◽  
Intragenic Deletions ◽  
High Concentrations ◽  
Nuclear Structures ◽  
Insight Into ◽  
Small Nuclear Ribonucleoproteins

Cajal bodies (CBs) are nuclear structures involved in RNA metabolism that accumulate high concentrations of small nuclear ribonucleoproteins (snRNPs). Notably, CBs preferentially associate with specific genomic loci in interphase human cells, including several snRNA and histone gene clusters. To uncover functional elements involved in the interaction of genes and CBs, we analyzed the expression and subcellular localization of stably transfected artificial arrays of U2 snRNA genes. Although promoter substitution arrays colocalized with CBs, constructs containing intragenic deletions did not. Additional experiments identified factors within CBs that are important for association with the native U2 genes. Inhibition of nuclear export or targeted degradation of U2 snRNPs caused a marked decrease in the levels of U2 snRNA in CBs and strongly disrupted the interaction with U2 genes. Together, the results illustrate a specific requirement for both the snRNA transcripts as well as the presence of snRNPs (or snRNP proteins) within CBs. Our data thus provide significant insight into the mechanism of CB interaction with snRNA loci, strengthening the putative role for this nuclear suborganelle in snRNP biogenesis.

Orientation-dependent transcriptional activator upstream of a human U2 snRNA gene

1985 ◽  
Vol 5 (7) ◽  
pp. 1560-1570
Author(s):  
M Ares ◽  
M Mangin ◽  
A M Weiner
Keyword(s):  
Rna Polymerase Ii ◽  
Transcription Unit ◽  
Limiting Factor ◽  
Flanking Sequence ◽  
U2 Snrna ◽  
Snrna Gene ◽  
Direct Initiation ◽  
Base Pair Deletion ◽  
Sequence Region ◽  
Transcription Complexes

We examined the structure of the promoter for the human U2 snRNA gene, a strong RNA polymerase II transcription unit without an obvious TATA box. A set of 5' deletions was constructed and assayed for the ability to direct initiation of U2 snRNA after microinjection into Xenopus oocytes. Sequences between positions -295 and -218 contain an activator element which stimulates accurate initiation by 20- to 50-fold, although as few as 62 base pairs of 5' flanking sequence are sufficient to direct the accurate initiation of U2 RNA. When the activator was recloned in the proper orientation at either of two different upstream locations, the use of the normal U2 start site was stimulated. Inversion of the element destroyed the stimulation of accurate U2 initiation, but initiation at aberrant upstream start sites was enhanced by the element in both orientations. A 4-base-pair deletion that destroyed the activity of the element lies within a sequence (region III) which is highly conserved among U2 genes from different organisms. Mutations in the activator also affected the ability of the U2 template to compete with a wild-type U1 gene in coinjection experiments. We propose that the element enhances the efficiency of transcription in part by facilitating the association of a limiting factor with transcription complexes. Human U1 snRNA genes possess a region homologous to U2 region III, and we suggest that upstream activator elements may be a general feature of snRNA promoters.

scholarly journals Activity of chimeric U small nuclear RNA (snRNA)/mRNA genes in transfected protoplasts of Nicotiana plumbaginifolia: U snRNA 3'-end formation and transcription initiation can occur independently in plants.

1993 ◽  
Vol 13 (10) ◽  
pp. 6403-6415 ◽  
Author(s):  
S Connelly ◽  
W Filipowicz
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Transcription Initiation ◽  
Gene Promoter ◽  
Nicotiana Plumbaginifolia ◽  
Gene Promoters ◽  
Coding Region ◽  
Pol Ii ◽  
U2 Snrna ◽  
Snrna Gene

Formation of the 3' ends of RNA polymerase II (Pol II)-specific U small nuclear RNAs (U snRNAs) in vertebrate cells is dependent upon transcription initiation from the U snRNA gene promoter. Moreover, U snRNA promoters are unable to direct the synthesis of functional polyadenylated mRNAs. In this work, we have investigated whether U snRNA 3'-end formation and transcription initiation are also coupled in plants. We have first characterized the requirements for 3'-end formation of an Arabidopsis U2 snRNA expressed in transfected protoplasts of Nicotiana plumbaginifolia. We found that the 3'-end-adjacent sequence CA (N)3-10AGTNNAA, conserved in plant Pol II-specific U snRNA genes, is essential for the 3'-end formation of U2 transcripts and, similar to the vertebrate 3' box, is highly tolerant to mutation. The 3'-flanking regions of an Arabidopsis U5 and a maize U2 snRNA gene can effectively substitute for the Arabidopsis U2 3'-end formation signal, indicating that these signals are functionally equivalent among different Pol II-transcribed snRNA genes. The plant U snRNA 3'-end formation signal can be recognized irrespective of whether transcription initiation occurs at U snRNA or mRNA gene promoters, although efficiency of 3' box utilization is higher when transcription initiation occurs at the U snRNA promoter. Moreover, transcripts initiated from the U2 gene promoter can be spliced and polyadenylated. Transcription from a Pol III-specific plant U snRNA gene promoter is not compatible with polyadenylation. Finally, we reveal that initiation at a Pol II-specific plant U snRNA gene promoter can occur in the absence of the snRNA coding region and a functional snRNA 3'-end formation signal, demonstrating that these sequences play no role in determining the RNA polymerase specificity of plant U snRNA genes.

Sign in / Sign up

Export Citation Format

Share Document