scholarly journals An alternative D. melanogaster 7SK snRNP

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Duy Nguyen ◽  
Nicolas Buisine ◽  
Olivier Fayol ◽  
Annemieke A. Michels ◽  
Olivier Bensaude ◽  
...  
Keyword(s):  
Secondary Structure ◽  
Rna Polymerase Ii ◽  
Biological Function ◽  
Expression Profiles ◽  
Structure And Function ◽  
Small Nuclear Rna ◽  
Primary Sequence ◽  
Nuclear Rna ◽  
And Function

Abstract Background The 7SK small nuclear RNA (snRNA) found in most metazoans is a key regulator of P-TEFb which in turn regulates RNA polymerase II elongation. Although its primary sequence varies in protostomes, its secondary structure and function are conserved across evolutionary distant taxa. Results Here, we describe a novel ncRNA sharing many features characteristic of 7SK RNAs, in D. melanogaster. We examined the structure of the corresponding gene and determined the expression profiles of the encoded RNA, called snRNA:7SK:94F, during development. It is probably produced from the transcription of a lncRNA which is processed into a mature snRNA. We also addressed its biological function and we show that, like dm7SK, this alternative 7SK interacts in vivo with the different partners of the P-TEFb complex, i.e. HEXIM, LARP7 and Cyclin T. This novel RNA is widely expressed across tissues. Conclusion We propose that two distinct 7SK genes might contribute to the formation of the 7SK snRNP complex in D. melanogaster.

U2 small nuclear RNA is remarkably conserved between Schizosaccharomyces pombe and mammals

1988 ◽  
Vol 8 (12) ◽  
pp. 5575-5580
Author(s):  
P Brennwald ◽  
G Porter ◽  
J A Wise
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Secondary Structure ◽  
Schizosaccharomyces Pombe ◽  
Small Nuclear Rna ◽  
Primary Sequence ◽  
Cloning And Sequencing ◽  
Sequence Identity ◽  
Human Counterpart ◽  
Nuclear Rna ◽  
Rna Blot Analysis

We report the molecular cloning and sequencing of the most abundant trimethylguanosine-capped small nuclear RNA from the fission yeast Schizosaccharomyces pombe, a highly conserved homolog of mammalian U2 small nuclear RNA. This RNA is 186 nucleotides in length, just 2 nucleotides shorter than its human counterpart; this is in contrast to Saccharomyces cerevisiae U2, which is 1,175 nucleotides long. Moreover, the secondary structure of Schizosaccharomyces pombe U2 is virtually identical to that of mammalian U2, including the 3' half of the RNA, which shows limited primary sequence identity. Northern (RNA) blot analysis revealed that the size of this RNA is conserved not only in fission yeasts but in many organisms, including other ascomycetes.

scholarly journals Structural analyses of the 7SK ribonucleoprotein (RNP), the most abundant human small RNP of unknown function.

1991 ◽  
Vol 11 (7) ◽  
pp. 3432-3445 ◽  
Author(s):  
D A Wassarman ◽  
J A Steitz
Keyword(s):  
Secondary Structure ◽  
Rnase H ◽  
Small Nuclear Rna ◽  
Base Pairing ◽  
Structural Determinants ◽  
Nuclear Rna ◽  
Sequence Complementarity ◽  
Associated Proteins ◽  
Stem Structure

The human 7SK ribonucleoprotein (RNP) has been analyzed to determine its RNA secondary structure and protein constituents. HeLa cell 7SK RNA alone and within its RNP have been probed by chemical modification and enzymatic cleavage, and sites of modification or cleavage have been mapped by primer extension. The resulting secondary structure suggests that structural determinants necessary for capping (a 5' stem followed by the sequence AUPuUPuC) and nuclear migration (the sequence AUPuUPuC) of 7SK RNA may be similar to those for U6 small nuclear RNA (snRNA). It also supports existence of a 3' stem structure which could serve to self-prime cDNA synthesis during pseudogene formation. Oligonucleotide-directed RNase H digestion indicated regions of 7SK RNA capable of base pairing with other nucleic acids. Antisense 2'-O-methyl RNA oligonucleotides were used to affinity select the 7SK RNP from an in vivo 35S-labeled cell sonic extract and identify eight associated proteins of 83, 48, 45, 43, 42, 21, 18, and 13 kDa. 7SK RNA has extensive sequence complementarity to U4 snRNA, within the U4/U6 base pairing domain, and also to U11 snRNA. The possibility that the 7SK RNP is an unrecognized component of the pre-mRNA processing machinery is discussed.

Secondary structure of U6 small nuclear RNA: implications for spliceosome assembly

2010 ◽  
Vol 38 (4) ◽  
pp. 1099-1104 ◽  
Author(s):  
Elizabeth A. Dunn ◽  
Stephen D. Rader
Keyword(s):  
Secondary Structure ◽  
Small Nuclear Rna ◽  
Stem Loop ◽  
New Model ◽  
Rna Molecules ◽  
U6 Snrna ◽  
Small Nuclear Ribonucleoprotein ◽  
Nuclear Rna ◽  
High Level ◽  
And Function

U6 snRNA (small nuclear RNA), one of five RNA molecules that are required for the essential process of pre-mRNA splicing, is notable for its high level of sequence conservation and the important role it is thought to play in the splicing reaction. Nevertheless, the secondary structure of U6 in the free snRNP (small nuclear ribonucleoprotein) form has remained elusive, with predictions changing substantially over the years. In the present review we discuss the evidence for existing models and critically evaluate a fundamental assumption of these models, namely whether the important 3′ ISL (3′ internal stem–loop) is present in the free U6 particle, as well as in the active splicing complex. We compare existing models of free U6 with a newly proposed model lacking the 3′ ISL and evaluate the implications of the new model for the structure and function of U6's base-pairing partner U4 snRNA. Intriguingly, the new model predicts a role for U4 that was unanticipated previously, namely as an activator of U6 for assembly into the splicing machinery.

Structural analyses of the 7SK ribonucleoprotein (RNP), the most abundant human small RNP of unknown function

1991 ◽  
Vol 11 (7) ◽  
pp. 3432-3445
Author(s):  
D A Wassarman ◽  
J A Steitz
Keyword(s):  
Secondary Structure ◽  
Rnase H ◽  
Small Nuclear Rna ◽  
Base Pairing ◽  
Structural Determinants ◽  
Nuclear Rna ◽  
Sequence Complementarity ◽  
Associated Proteins ◽  
Stem Structure

The human 7SK ribonucleoprotein (RNP) has been analyzed to determine its RNA secondary structure and protein constituents. HeLa cell 7SK RNA alone and within its RNP have been probed by chemical modification and enzymatic cleavage, and sites of modification or cleavage have been mapped by primer extension. The resulting secondary structure suggests that structural determinants necessary for capping (a 5' stem followed by the sequence AUPuUPuC) and nuclear migration (the sequence AUPuUPuC) of 7SK RNA may be similar to those for U6 small nuclear RNA (snRNA). It also supports existence of a 3' stem structure which could serve to self-prime cDNA synthesis during pseudogene formation. Oligonucleotide-directed RNase H digestion indicated regions of 7SK RNA capable of base pairing with other nucleic acids. Antisense 2'-O-methyl RNA oligonucleotides were used to affinity select the 7SK RNP from an in vivo 35S-labeled cell sonic extract and identify eight associated proteins of 83, 48, 45, 43, 42, 21, 18, and 13 kDa. 7SK RNA has extensive sequence complementarity to U4 snRNA, within the U4/U6 base pairing domain, and also to U11 snRNA. The possibility that the 7SK RNP is an unrecognized component of the pre-mRNA processing machinery is discussed.

scholarly journals U2 small nuclear RNA is remarkably conserved between Schizosaccharomyces pombe and mammals.

1988 ◽  
Vol 8 (12) ◽  
pp. 5575-5580 ◽  
Author(s):  
P Brennwald ◽  
G Porter ◽  
J A Wise
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Secondary Structure ◽  
Schizosaccharomyces Pombe ◽  
Small Nuclear Rna ◽  
Primary Sequence ◽  
Cloning And Sequencing ◽  
Sequence Identity ◽  
Human Counterpart ◽  
Nuclear Rna ◽  
Rna Blot Analysis

We report the molecular cloning and sequencing of the most abundant trimethylguanosine-capped small nuclear RNA from the fission yeast Schizosaccharomyces pombe, a highly conserved homolog of mammalian U2 small nuclear RNA. This RNA is 186 nucleotides in length, just 2 nucleotides shorter than its human counterpart; this is in contrast to Saccharomyces cerevisiae U2, which is 1,175 nucleotides long. Moreover, the secondary structure of Schizosaccharomyces pombe U2 is virtually identical to that of mammalian U2, including the 3' half of the RNA, which shows limited primary sequence identity. Northern (RNA) blot analysis revealed that the size of this RNA is conserved not only in fission yeasts but in many organisms, including other ascomycetes.

scholarly journals Small nuclear RNA transcription and ribonucleoprotein assembly in early Xenopus development.

1983 ◽  
Vol 97 (1) ◽  
pp. 62-72 ◽  
Author(s):  
D J Forbes ◽  
T B Kornberg ◽  
M W Kirschner
Keyword(s):  
Rna Polymerase Ii ◽  
Sedimentation Coefficient ◽  
Small Nuclear Rna ◽  
Early Cleavage ◽  
Cell Stage ◽  
U1 Snrna ◽  
Nuclear Rna ◽  
Xenopus Egg ◽  
Nuclear Number ◽  
And Function

The Xenopus egg and embryo, throughout the transcriptionally inactive early cleavage period, were found to contain a store of approximately 8 X 10(8) molecules of the small nuclear RNA (snRNA) U1, sufficient for 4,000-8,000 nuclei. In addition, when transcription is activated at the twelfth cleavage (4,000 cell-stage), the snRNAs U1, U2, U4, U5, and U6 are major RNA polymerase II products. From the twelfth cleavage to gastrulation, U1 RNA increases sevenfold in 4 h, paralleling a similar increase in nuclear number. This level of snRNA transcription is much greater than that typical of somatic cells, implying a higher rate of U1 transcription or a greater number of U1 genes active in the embryo. The Xenopus egg also contains snRNP proteins, since it has the capacity to package exogenously added snRNA into immunoprecipitable snRNP particles, which resemble endogenous particles in both sedimentation coefficient and T1 RNase digestibility. SnRNP proteins may recognize conserved secondary structure of U1 snRNA since efficient packaging of both mouse and Drosophila U1 RNAs, differing 30% in sequence, occurs. The Xenopus egg and embryo can be used to pose a number of interesting questions about the transcription, assembly, and function of snRNA.

Osseointegration interface of calcified bone and endosseous implants

1992 ◽  
Vol 50 (2) ◽  
pp. 1096-1097
Author(s):  
K.E. Krizan ◽  
J.E. Laffoon ◽  
M.J. Buckley
Keyword(s):  
Structure And Function ◽  
Titanium Implants ◽  
En Bloc ◽  
Endosseous Implants ◽  
Ultrastructural Studies ◽  
The Past ◽  
Cacodylate Buffer ◽  
One Year ◽  
And Function

With increase use of tissue-integrated prostheses in recent years it is a goal to understand what is happening at the interface between haversion bone and bulk metal. This study uses electron microscopy (EM) techniques to establish parameters for osseointegration (structure and function between bone and nonload-carrying implants) in an animal model. In the past the interface has been evaluated extensively with light microscopy methods. Today researchers are using the EM for ultrastructural studies of the bone tissue and implant responses to an in vivo environment. Under general anesthesia nine adult mongrel dogs received three Brånemark (Nobelpharma) 3.75 × 7 mm titanium implants surgical placed in their left zygomatic arch. After a one year healing period the animals were injected with a routine bone marker (oxytetracycline), euthanized and perfused via aortic cannulation with 3% glutaraldehyde in 0.1M cacodylate buffer pH 7.2. Implants were retrieved en bloc, harvest radiographs made (Fig. 1), and routinely embedded in plastic. Tissue and implants were cut into 300 micron thick wafers, longitudinally to the implant with an Isomet saw and diamond wafering blade [Beuhler] until the center of the implant was reached.

Sign in / Sign up

Export Citation Format

Share Document