Small nuclear RNA (snRNA) genes contain strong promoters capable of initiating transcription once every 4 s. Studies on the human U1 snRNA gene, carried out in other laboratories, showed that sequences within 400 bp of the 5 flanking region are sufficient for maximal levels of transcription both in vivo and in frog oocytes [reviewed in Dahlberg and Lund (1988)]. We studied the expression of a human U3 snRNA gene by injecting 5 deletion mutants into frog oocytes. The results show that sequences more than 500 bp upstream of the U3 snRNA gene have a 2-3-fold stimulatory effect on the U3 snRNA synthesis. These results indicate that the human U3 snRNA gene is different from human U1 snRNA gene in containing regulatory elements more than 500 bp upstream. The U3 snRNA gene upstream sequences contain an AluI homologous sequence in the -1200 region; these AluI sequences were transcribed in vitro and in frog oocytes but were not detectable in HeLa cells.
Basal transcription from the human RNA polymerase III U6 promoter depends on a TATA box that recruits the TATA box-binding protein (TBP) and a proximal sequence element that recruits the small nuclear RNA (snRNA)-activating protein complex (SNAPc). TBP consists of a conserved carboxyl-terminal domain that performs all known functions of the protein and a nonconserved amino-terminal region of unknown function. Here, the amino-terminal region is shown to down-regulate binding of TBP to the U6 TATA box, mediate cooperative binding with SNAPc to the U6 promoter, and enhance U6 transcription.. ...
Small nuclear ribonucleic acid (snRNA), also commonly referred to as U-RNA, is a class of small RNA molecules that are found within the splicing speckles and Cajal bodies of the cell nucleus in eukaryotic cells. The length of an average snRNA is approximately 150 nucleotides. They are transcribed by either RNA polymerase II or RNA polymerase III. Their primary function is in the processing of pre-messenger RNA (hnRNA) in the nucleus. They have also been shown to aid in the regulation of transcription factors (7SK RNA) or RNA polymerase II (B2 RNA), and maintaining the telomeres. snRNA are always associated with a set of specific proteins, and the complexes are referred to as small nuclear ribonucleoproteins (snRNP, often pronounced "snurps"). Each snRNP particle is composed of a snRNA component and several snRNP-specific proteins (including Sm proteins, a family of nuclear proteins). The most common snRNA components of these complexes are known, respectively, as: U1 spliceosomal RNA, U2 ...
Dergai, O., Cousin, P., Gouge, J., Satia, K., Praz, V., Kuhlman, T., Lhote, P., Vannini, A., Hernandez, N. (May 2018) Mechanism of selective recruitment of RNA polymerases II and III to snRNA gene promoters. Genes Dev, 32 (9-10). pp. 711-722. ISSN 0890-9369 Denissov, S., Van Driel, M., Voit, R., Hekkelman, M., Hulsen, T., Hernandez, N., Grummt, I., Wehrens, R., Stunnenberg, H. (February 2007) Identification of novel functional TBP-binding sites and general factor repertoires. Embo Journal, 26 (4). pp. 944-954. ISSN 0261-4189 Emran, F., Florens, L., Ma, B., Swanson, S. K., Washburn, M. P., Hernandez, N. (August 2006) A role for Yin Yang-1 (YY1) in the assembly of snRNA transcription complexes. Gene, 377. pp. 96-108. ISSN 0378-1119 (Print) Kim, Y. S., Kim, J. M., Jung, D. L., Kang, J. E., Lee, S., Kim, J. S., Seol, W., Shin, H. C., Kwon, H. S., Van Lint, C., Hernandez, N., Hur, M. W. (June 2005) Artificial zinc finger fusions targeting Sp1-binding sites and the trans-activator-responsive element ...
The concept of the gene has been constantly challenged by new discoveries in the life sciences. Recent challenging observations include the high frequency of alternative splicing events and the common transcription of non-protein-coding-RNAs (ncRNAs) from the genome. The latter has long been considered noise in biological systems. Multiple lines of evidence from genomic studies indicate that alternative splicing and ncRNA play important roles in expanding proteome diversity in eukaryotes. Here, the aim is to find the link between alternative splicing and ncRNAs by studying the expression profile of the spliceosomal snRNAs (U snRNA).. Spliceosomal snRNAs are essential for pre-mRNA splicing in eukaryotes. They participate in splice site selection, recruitment of protein factors and catalyzing the splicing reaction. Because of this, both the abundance and diversity of U snRNAs were expected to be large. In our study we deeply analyzed the U snRNA population in primates using a combination of ...
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Complete information for SNAPC2 gene (Protein Coding), Small Nuclear RNA Activating Complex Polypeptide 2, including: function, proteins, disorders, pathways, orthologs, and expression. GeneCards - The Human Gene Compendium
Complete information for LSM5 gene (Protein Coding), LSM5 Homolog, U6 Small Nuclear RNA And MRNA Degradation Associated, including: function, proteins, disorders, pathways, orthologs, and expression. GeneCards - The Human Gene Compendium
LSM1 antibody (LSM1 homolog, U6 small nuclear RNA associated (S. cerevisiae)) for IP, WB. Anti-LSM1 pAb (GTX130104) is tested in Human samples. 100% Ab-Assurance.
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Princeton University was ranked 8th in the world, behind six other U.S. universities and Oxford in the U.K., out of nearly 1,500 institutions in the U.S. and 80 other countries, according to U.S. News and World Report. The university was named best in the U.S. last month. 6 N.J. Schools Named among Best in World […]. ...
Looking for online definition of LSM5 homolog, U6 small nuclear RNA associated in the Medical Dictionary? LSM5 homolog, U6 small nuclear RNA associated explanation free. What is LSM5 homolog, U6 small nuclear RNA associated? Meaning of LSM5 homolog, U6 small nuclear RNA associated medical term. What does LSM5 homolog, U6 small nuclear RNA associated mean?
Pol II (RNA polymerase II) transcribes the genes encoding proteins and non-coding snRNAs (small nuclear RNAs). The largest subunit of Pol II contains a distinctive CTD (C-terminal domain) comprising a repetitive heptad amino acid sequence, Tyr1-Ser2-Pro3-Thr4-Ser5-Pro6-Ser7. This domain is now known to play a major role in the processes of transcription and co-transcriptional RNA processing in expression of both snRNA and protein-coding genes. The heptapeptide repeat unit can be extensively modified in vivo and covalent modifications of the CTD during the transcription cycle result in the ordered recruitment of RNA-processing factors. The most studied modifications are the phosphorylation of the serine residues in position 2 and 5 (Ser2 and Ser5), which play an important role in the co-transcriptional processing of both mRNA and snRNA. An additional, recently identified CTD modification, phosphorylation of the serine residue in position 7 (Ser7) of the heptapeptide, is however specifically ...
Eukaryotic cells contain a set of low molecular weight nuclear RNAs. One of the more abundant of these is termed U2 RNA. The possibility that U2 RNA is hydrogen-bonded to complementary sequences in other nuclear RNAs was investigated. Cultured human (HeLa) cells were treated with a psoralen derivative that cross-links RNA chains that are base-paired with one another. High molecular weight heterogeneous nuclear RNA was isolated under denaturing conditions, and the psoralen cross-links were reversed. Electrophoresis of the released RNA and hybridization with a human cloned U2 DNA probe revealed that U2 is hydrogen-bonded to complementary sequences in heterogeneous nuclear RNA in vivo. In contrast, U2 RNA is not base-paired with nucleolar RNA, which contains the precursors of ribosomal RNA. The results suggest that U2 RNA participates in messenger RNA processing in the nucleus. ...
A phosphoprotein adapter involved in the XPO1-mediated U snRNA export from the nucleus. Bridge components required for U snRNA export, the cap binding complex (CBC)-bound snRNA on the one hand and the GTPase Ran in its active GTP-bound form together with the export receptor XPO1 on the other. Its phosphorylation in the nucleus is required for U snRNA export complex assembly and export, while its dephosphorylation in the cytoplasm causes export complex disassembly. It is recycled back to the nucleus via the importin alpha/beta heterodimeric import receptor. The directionality of nuclear export is thought to be conferred by an asymmetric distribution of the GTP- and GDP-bound forms of Ran between the cytoplasm and nucleus. Its compartmentalized phosphorylation cycle may also contribute to the directionality of export. Binds strongly to m7G-capped U1 and U5 small nuclear RNAs (snRNAs) in a sequence-unspecific manner and phosphorylation-independent manner (By similarity). Plays also a role in the biogenesis
We develop a statistical mechanical model for RNA/RNA complexes with both intramolecular and intermolecular interactions. As an application of the model, we compute the free energy landscapes, which give the full distribution for all the possible conformations for spliceosomal snRNA complexes. Different snRNA experiments found contrasting structures, our free energy landscape theory shows why these structures emerge and how they compete with each other. In addition, the energy landscapes suggest possible mechanisms for the conformational switches in splicing. The change of the energy landscape shape gives information about the conformational changes. We find multiple (native-like and misfolded) intermediates formed through base-pairing rearrangements in snRNA complexes. Furthermore, the energy landscape gives the stabilities of all the possible (functional) intermediates and such information is directly related to splicing efficiency ...
Pseudouridine (Psi) residues were localized in the Saccharomyces cerevisiae spliceosomal U small nuclear RNAs (UsnRNAs) by using the chemical mapping method. In contrast to vertebrate UsnRNAs, S. cerevisiae UsnRNAs contain only a few Psi residues, which are located in segments involved in intermolecular RNA-RNA or RNA-protein interactions. At these positions, UsnRNAs are universally modified. When yeast mutants disrupted for one of the several pseudouridine synthase genes (PUS1, PUS2, PUS3, and PUS4) or depleted in rRNA-pseudouridine synthase Cbf5p were tested for UsnRNA Psi content, only the loss of the Pus1p activity was found to affect Psi formation in spliceosomal UsnRNAs. Indeed, Psi44 formation in U2 snRNA was abolished. By using purified Pus1p enzyme and in vitro-produced U2 snRNA, Pus1p is shown here to catalyze Psi44 formation in the S. cerevisiae U2 snRNA. Thus, Pus1p is the first UsnRNA pseudouridine synthase characterized so far which exhibits a dual substrate specificity, acting on ...
Nuclear pre-mRNA splicing takes places in a large RNP complex, the spliceosome, which is assembled in an ordered multistep process. It consists of five small nuclear RNAs (the U1, U2, U4, U5, and U6 snRNAs) and more than 100 proteins, as recent proteomic analyses have determined (15, 16, 39). The spliceosome shows characteristic dynamics during assembly and splicing catalysis. For example, only the U2, U5, and U6 snRNAs participate in the catalytic center of the spliceosome, whereas the U1 and U4 snRNAs play essential roles only during the early assembly stages. After completion of the two-step splicing reaction and the release of mRNA and lariat products, the spliceosome disassembles into its components. Before entering a new cycle, at least some the components presumably must be reactivated. However, very little is known about this recycling phase of the spliceosome cycle.. The U4, U5, and U6 snRNAs enter the prespliceosome in the form of the 25S U4/U6.U5 tri-snRNP but are released from the ...
U6 snRNA phosphodiesterase; Phosphodiesterase responsible for the U6 snRNA 3 end processing. Acts as an exoribonuclease (RNase) responsible for trimming the poly(U) tract of the last nucleotides in the pre-U6 snRNA molecule, leading to the formation of mature U6 snRNA (279 aa ...
The removal of introns from pre-mRNA transcripts is an essential step in the expression of almost all human genes. we are collaborating with several groups to d...
Five small nuclear RNAs (snRNAs) (U1, U2, U4, U5, U6) found in the nucleus of eukaryotic cells mediate the excision of introns from pre-mRNAs. The structure and expression of the snRNA components have been well documented in animal and yeast systems but little information has existed on the structure and expression of the splicesomal snRNAs involved in plant intron excision. To further define the snRNA components involved in intron excision, a clone library has been constructed from anti-m$\sb3$G immunoprecipitated snRNAs expressed in pea seedlings. cDNA clones representing U1, U2, U4, and U5 snRNAs expressed in seedling tissue have been isolated and sequenced. Comparison of the pea snRNA variants with other organisms suggest that functionally important primary sequences are conserved phylogenetically even though the overall sequences have diverged substantially. Structural variations occur in regions required for U1-specific protein binding suggesting that alternate U1 snRNP particles may exist ...
The authors also were interested in using endogenous promoters to express gRNA and Cas9. They identified three U6 snRNA genes in the Tribolium genome, cloned two putative promoter fragments and placed them upstream of the eGFP1 gRNA, then injected them into Pig-19 embryos along with Cas9 mRNA. They found very similar results to injected in-vitro synthesized gRNA, suggesting endogenous promoters can be used effectively to drive in-vivo expression of gRNA and Cas9 in Tribolium.. The authors also used homology-dependent repair to generate knock-ins; specifically, they attempted to replace a green fluorescent transgene with a red transgene, with homology arms flanking the donor transgene of 0.7 kb and 1 kb (Figure 2). DsRed fluorescence was seen in 8-20% of G0 larvae, and 0-10% of second-generation larvae; they verified the conversion by sequencing.. Overall, the authors demonstrate that CRISPR / Cas9 can be used in Tribolium to make targeted knockouts and gene conversions, and that endogenous U6 ...
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Nucleolar localization of U4 and U5 snRNAs does not depend on U6 snRNA. Fluorescein-labeled U4 or U5 snRNA were injected into the nuclei of Xenopus oocytes that
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@U2 provides U2 news, U2 photographs, U2 lyrics, and other U2 information in a non-profit, educational setting for anyone interested in learning about the Irish rock band U2.
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Most mammalian snoRNAs are encoded within the introns of pre-mRNA genes. The majority of snoRNAs are released from the pre-mRNA via a splicing-dependent pathway, while some are processed via endonucleolytic cleavage of the pre-mRNA. The remaining mammalian snoRNAs, such as U3, U8 and U13, are expressed from independent genes and contain an m3G cap structure (9, 30, 43, 52). The biogenesis of box C/D snoRNAs takes place in the nucleoplasm, where the nascent transcribed RNAs are processed, assembled into RNPs, and transported to the nucleolus. The box C/D motif has been shown to be essential for each of these steps in snoRNP biogenesis. This RNA element is a protein binding site that has been proposed to participate in both the biogenesis and function of snoRNAs via the selective recruitment of specific box C/D binding factors (9, 41, 52).. Four common core proteins are associated with the mature snoRNP, namely, fibrillarin (Nop1p in yeast), NOP56, NOP58, and the 15.5K protein (Snu13p in yeast) ...
Component of the Integrator complex, a complex involved in the small nuclear RNAs (snRNA) U1 and U2 transcription and in their 3-box-dependent processing. The Integrator complex is associated with the C-terminal domain (CTD) of RNA polymerase II largest subunit (POLR2A) and is recruited to the U1 and U2 snRNAs genes. Plays a role in DNA damage response (DDR) signaling during the S phase ...
Catalytic component of the Integrator (INT) complex, a complex involved in the small nuclear RNAs (snRNA) U1 and U2 transcription and in their 3-box-dependent processing. The Integrator complex is associated with the C-terminal domain (CTD) of RNA polymerase II largest subunit (POLR2A) and is recruited to the U1 and U2 snRNAs genes. Mediates the snRNAs 3 cleavage. Mediates recruitment of cytoplasmic dynein to the nuclear envelope, probably as component of the INT complex (PubMed:23904267).
Two types of spliceosomes catalyze splicing of pre-mRNAs. The major U2-type spliceosome is found in all eukaryotes and removes U2-type introns, which represent more than 99% of pre-mRNA introns. The minor U12-type spliceosome is found in some eukaryotes and removes U12-type introns, which are rare and have distinct splice consensus signals. The U12-type spliceosome consists of several small nuclear RNAs and associated proteins. This gene encodes a 65K protein that is a component of the U12-type spliceosome. This protein contains two RNA recognition motifs (RRMs), suggesting that it may contact one of the small nuclear RNAs of the minor spliceosome. [provided by RefSeq, Jul 2008 ...
Small nucleolar RNA RZ107/R87 refers to a group of related non-coding RNA (ncRNA) molecules which function in the biogenesis of other small nuclear RNAs (snRNAs). These small nucleolar RNAs (snoRNAs) are modifying RNAs and usually located in the nucleolus of the eukaryotic cell which is a major site of snRNA biogenesis. These two snoRNAs R87 and Z107 were identified in the plant Arabidopsis thaliana[1] and rice Oryza sativa[2] respectively. These related snoRNAs are predicted to belong to the C/D box class of snoRNAs which contain the conserved sequence motifs known as the C box (UGAUGA) and the D box (CUGA). Most of the members of the box C/D family function in directing site-specific 2-O-methylation of substrate RNAs.[3] ...
C/D box snoRNAs contain two short sequence motifs, box C and box D, located only a few nucleotides away from the 5′ and 3′ ends, respectively, generally as part of a typical 5′-3′ terminal stem-box structure (for a review see Bachellerie and Cavaillé, 1998). Immediately upstream from box D or from an additional box (D′) in the 5′ half, C/D snoRNAs feature sequence tracts, 10-21 nt in length, that are complementary to rRNA spanning the sites of 2′‐O‐ribose methylation. In the corresponding RNA duplexes, the ribose‐methylated nucleotide is always at the same location, paired to the fifth snoRNA nucleotide upstream from box D or box D′ (Kiss‐Laszlo et al., 1996; Nicoloso et al., 1996). In rRNA of the yeast Saccharomyces cerevisiae, cognate box C/D snoRNAs have been identified for 51 of the 55 ribose‐methylated sites (Lowe and Eddy, 1999). In mammals, however, a large fraction of the 105-107 expected rRNA 2′‐O‐ribose methylations (Maden, 1990) remained without a ...
Abstract: The recessive disorder poikiloderma with neutropenia (PN) is caused by mutations in the C16orf57 gene that encodes the highly conserved USB1 protein. Here, we present the 1.1 Å resolution crystal structure of human USB1, defining it as a member of the LigT-like superfamily of 2H phosphoesterases. We show that human USB1 is a distributive 3′-5′ exoribonuclease that posttranscriptionally removes uridine and adenosine nucleosides from the 3′ end of spliceosomal U6 small nuclear RNA (snRNA), directly catalyzing terminal 2′, 3′ cyclic phosphate formation. USB1 measures the appropriate length of the U6 oligo(U) tail by reading the position of a key adenine nucleotide (A102) and pausing 5 uridine residues downstream. We show that the 3′ ends of U6 snRNA in PN patient lymphoblasts are elongated and unexpectedly carry nontemplated 3′ oligo(A) tails that are characteristic of nuclear RNA surveillancetargets. Thus, our study reveals a novel quality control pathway in which ...
You are mistaken. ROCA PSEA could not sinned by default or change of its own previous decisions. Constant practice of any ecclesiastical authority in time to vary between the extremes and acrivia economia on the same issue. After retiring in split MP Metropolitan Laurus Group, formed in 2007 ROCA PSEA (now - it ROCOR Synod chaired by th en. Agafangel: in While the "fragments" of the ROCA as RPATs "ROCA (V)", RTOC IRPTSZ, RosPTs, etc., etc., etc. are schisms and parasinagogi), before taking the "sekachevtsev" are inseparable canonical continuation of that same Supreme Church Authority ROCA authorization th Patriarch Tikhon and educated at Metropolitan. Antonia by Decree # 362. Consequently, since the ROCA PSEA was a same old laws supreme ecclesiastical authority ROCA, it was not obliged to comply strictly with first developed their own decisions, and if necessary they could alter, amend or repeal all. So if the ROCA PSEA decided to take sekachevtsev-general without any yakih, it would not be a ...
The move to group sow housing by Cargill and other U.S. pork firms reflects an important shift in thinking about animal welfare, from consumers to large food -corporations
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Adaptive responses to stress are essential for cell and organismal survival. In metazoans, little is known about the impact of environmental stress on RNA homeostasis. By studying the regulation of a cadmium-induced gene named numr-1 in Caenorhabditis elegans, we discovered that disruption of RNA processing acts as a signal for environmental stress. We find that NUMR-1 contains motifs common to RNA splicing factors and influences RNA splicing in vivo. A genome-wide screen reveals that numr-1 is strongly and specifically induced by silencing of genes that function in basal RNA metabolism including subunits of the metazoan integrator complex. Human integrator processes snRNAs for functioning with splicing factors, and we find that silencing of C. elegans integrator subunits disrupts snRNA processing, causes aberrant pre-mRNA splicing, and induces the heat shock response. Cadmium, which also strongly induces numr-1, has similar effects on RNA and the heat shock response. Lastly, we find that heat shock
Adaptive responses to stress are essential for cell and organismal survival. In metazoans, little is known about the impact of environmental stress on RNA homeostasis. By studying the regulation of a cadmium-induced gene named numr-1 in Caenorhabditis elegans, we discovered that disruption of RNA processing acts as a signal for environmental stress. We find that NUMR-1 contains motifs common to RNA splicing factors and influences RNA splicing in vivo. A genome-wide screen reveals that numr-1 is strongly and specifically induced by silencing of genes that function in basal RNA metabolism including subunits of the metazoan integrator complex. Human integrator processes snRNAs for functioning with splicing factors, and we find that silencing of C. elegans integrator subunits disrupts snRNA processing, causes aberrant pre-mRNA splicing, and induces the heat shock response. Cadmium, which also strongly induces numr-1, has similar effects on RNA and the heat shock response. Lastly, we find that heat shock
The 5 and 3 domains of yeast U6 snRNA contain sequences that are thought to be important for binding to Prp24 and Lsm proteins. By extensive mutational analysis of yeast U6 snRNA, we confirmed that the 3 terminal uridine tract of U6 snRNA is important for U6 binding to Lsm proteins in yeast. Binding of Prp24 protein to U6 RNA is dependent on or is strongly enhanced by U6 binding of Lsm proteins. This supports a model for U6 snRNP assembly in which U6 RNA binds to the Lsm2-8 core prior to binding Prp24 protein. Using compensatory base-pairing analysis, we show that at least half of the recently identified U6 telestem as well as a nucleotide sequence in the other half of the telestem are important for binding of U6 RNA to Prp24 protein. Surprisingly, disruption of base pairing in the unconfirmed half of the telestem enhanced U6-Prp24 binding. Truncation of the entire 3 terminal domain or nearly the entire 5 terminal domain of yeast U6 allowed for detectable levels of splicing to proceed in ...
A key question in the field of RNA regulation is how some exosome substrates, such as spliceosomal snRNAs and telomerase RNA, evade degradation and are processed into stable, functional RNA molecules. Typical feature of these non-coding RNAs is presence of the Sm complex at the 3′end of the mature RNA molecule. Here, we report that in Saccharomyces cerevisiae presence of intact Sm binding site is required for the exosome-mediated processing of telomerase RNA from a polyadenylated precursor into its mature form and is essential for its function in elongating telomeres. Additionally, we demonstrate that the same pathway is involved in the maturation of snRNAs. Furthermore, the insertion of an Sm binding site into an unstable RNA that is normally completely destroyed by the exosome, leads to its partial stabilization. We also show that telomerase RNA accumulates in Schizosaccharomyces pombe exosome mutants, suggesting a conserved role for the exosome in processing and degradation of telomerase RNA. In
Sera from some patients with systemic lupus erythematosus and other autoimmune diseases have antibodies against nuclear antigens. An example is anti-Sm sera, which recognize proteins associated with small nuclear RNA molecules [small nuclear ribonucleoprotein (snRNP) particles]. In this paper anti-Sm sera were used to probe immunoblots of various rat tissues. A previously unidentified Mr 28,000 polypeptide was recognized by these anti-Sm sera. This polypeptide, referred to as "N," is expressed in a tissue-specific manner, being most abundant in rat brain, less so in heart, and undetectable in the other tissues examined. Immunoprecipitation experiments using antibodies directed against the cap structure of small nuclear RNAs have demonstrated that N is a snRNP-associated polypeptide. Anti-Sm serum was also used to isolate a partial cDNA clone (lambda rb91) from a rat brain phage lambda gt11 cDNA expression library. On RNA blots, the 450-base-pair cDNA insert of this clone hybridized to a ...
Protein kinases are able to recognize their appropriate targets in a complex milieu of cellular protein. This process must be carried out with high fidelity to ensure proper signal transduction in eukaryotic cells (Hunter 2000). In this study, we attempted to obtain insight into this recognition by examining PKA variants that exhibit a stable association with substrates. This binding provided a facile assay that allowed us to identify domains in both enzyme and substrates that were important for PKA phosphorylation. The substrate domains identified were physically removed from the sites of phosphorylation and were required for efficient recognition by PKA both in vivo and in vitro. To the best of our knowledge, these studies are the first to show that such distal sequence elements in substrates are required for phosphorylation by PKA. These observations may help explain why only a fraction of proteins that contain a PKA consensus site are phosphorylated by this enzyme in vivo (Budovskayaet al. ...
A complex composed of RNA of the small nuclear RNA (snRNA) class and protein, found in the nucleus of a eukaryotic cell. These are typically named after the snRNA(s) they contain, e.g. U1 snRNP or U4/U6 snRNP. Many, but not all, of these complexes are involved in splicing of nuclear mRNAs. [GOC:krc, GOC:mah, ISBN:0879695897]