Nop10 is a component of the small nucleolar ribonucleoprotein particles containing H/ACA-type snoRNAs (H/ACA snoRNPs). H/ACA snoRNPs are primarily responsible for catalysing the isomerisation of uridine to pseudouridine (Psi) in ribosomal and other cellular RNAs. The protein component of the H/ACA snoRNP consists of Cbf5, Gar1, Nhp2 and Nop10. The complex contains a stable core composed of Cbf5 and Nop10, to which Gar1 and Nhp2 subsequently bind. Nop10 has an essential role in the assembly and activity of these particles and binds directly to the Cbf5 to form the minimal active enzyme in archaea. The complex interacts with snoRNAs, Nop10 acting as a molecular adaptor for guiding snoRNP assembly [].
H/ACA ribonucleoprotein particles (RNPs) are a family of RNA pseudouridine synthases that specify modification sites through guide RNAs. The function of these H/ACA RNPs is essential for biogenesis of the ribosome, splicing of precursor mRNAs (pre-mRNAs), maintenance of telomeres and probably for additional cellular processes []. All H/ACA RNPs contain a specific RNA component (snoRNA or scaRNA) and at least four proteins common to all such particles: Cbf5, Gar1, Nhp2 and Nop10. These proteins are highly conserved from yeast to mammals and homologues are also present in archaea []. The H/ACA protein complex contains a stable core composed of Cbf5 and Nop10, to which Gar1 and Nhp2 subsequently bind [].In eukaryotes Nop10 is a nucleolar protein that is specifically associated with H/ACA snoRNAs. It is essential for normal 18S rRNA production and rRNA pseudouridylation by the ribonucleoprotein particles containing H/ACA snoRNAs (H/ACA snoRNPs). Nop10 is probably necessary for the stability of these RNPs []. The Nop10 domain structure has a rubredoxin-like fold.
H/ACA ribonucleoprotein particles (RNPs) are a family of RNA pseudouridine synthases that specify modification sites through guide RNAs. The function of these H/ACA RNPs is essential for biogenesis of the ribosome, splicing of precursor mRNAs (pre-mRNAs), maintenance of telomeres and probably for additional cellular processes []. All H/ACA RNPs contain a specific RNA component (snoRNA or scaRNA) and at least four proteins common to all such particles: Cbf5, Gar1, Nhp2 and Nop10. These proteins are highly conserved from yeast to mammals and homologues are also present in archaea []. The H/ACA protein complex contains a stable core composed of Cbf5 and Nop10, to which Gar1 and Nhp2 subsequently bind [].In eukaryotes Nop10 is a nucleolar protein that is specifically associated with H/ACA snoRNAs. It is essential for normal 18S rRNA production and rRNA pseudouridylation by the ribonucleoprotein particles containing H/ACA snoRNAs (H/ACA snoRNPs). Nop10 is probably necessary for the stability of these RNPs [].
H/ACA ribonucleoprotein particles (RNPs) are a family of RNA pseudouridine synthases that specify modification sites through guide RNAs. The function of these H/ACA RNPs is essential for biogenesis of the ribosome, splicing of precursor mRNAs (pre-mRNAs), maintenance of telomeres and probably for additional cellular processes []. All H/ACA RNPs contain a specific RNA component (snoRNA or scaRNA) and at least four proteins common to all such particles: Cbf5, Gar1, Nhp2 and Nop10. These proteins are highly conserved from yeast to mammals and homologues are also present in archaea []. The H/ACA protein complex contains a stable core composed of Cbf5 and Nop10, to which Gar1 and Nhp2 subsequently bind [].This entry represents H/ACA ribonucleoprotein complex subunit NHP2 and similar proteins from eukaryotes, including NHP2-like protein 1 from mammals (SNU13 homologue) and 13 kDa ribonucleoprotein-associated protein (SNU13) from yeast.Nhp2 is part of a complex which catalyses pseudouridylation of rRNA and is required for rRNA biogenesis. This involves the isomerisation of uridine such that the ribose is subsequently attached to C5, instead of the normal N1. Pseudouridine ("psi") residues may serve to stabilise the conformation of rRNAs. Nph2 associates non-specifically with RNA secondary structures instead of directly binding to an specific RNA motif. This protein seem to have evolved from the archaeal ribosomal L7Ae protein family []. Human SNU13 homologue is involved in pre-mRNA splicing as component of the spliceosome []. The protein undergoes a conformational change upon RNA-binding [].SNU13 from Saccharomyces cerevisiae (Baker's yeast) is also a component of the spliceosome and rRNA processing machinery, required for splicing of pre-mRNA and essential for the accumulation and stability of U4 snRNA, U6 snRNA, and box C/D snoRNAs [, , ].
The box H/ACA ribonucleoproteins (RNPs) are protein-RNA complexes responsible for pseudouridylation, the most abundant post-transcriptional modification of cellular RNAs []. Each distinct H/ACA RNA assembles with a common set of four proteins, Cbf5 (NAP57 in rodents and dyskerin in humans), Nop10, Nhp2 (L7Ae in archaea) and Gar1 []. Shq1 is an essential assembly factor for H/ACA ribonucleoproteins (RNPs) required for ribosome biogenesis, pre-mRNA splicing, and telomere maintenance []. It interacts with Cbf5 and may function as an assembly chaperone that protects the Cbf5 protein complexes from non-specific RNA binding and aggregation before assembly of H/ACA RNA [].
H/ACA ribonucleoprotein particles (RNPs) are a family of RNA pseudouridine synthases that specify modification sites through guide RNAs. The function of these H/ACA RNPs is essential for biogenesis of the ribosome, splicing of precursor mRNAs (pre-mRNAs), maintenance of telomeres and probably for additional cellular processes []. All H/ACA RNPs contain a specific RNA component (snoRNA or scaRNA) and at least four proteins common to all such particles: Cbf5, Gar1, Nhp2 and Nop10. These proteins are highly conserved from yeast to mammals and homologues are also present in archaea []. The H/ACA protein complex contains a stable core composed of Cbf5 and Nop10, to which Gar1 and Nhp2 subsequently bind [].Naf1 is an RNA-binding protein required for the maturation of box H/ACA snoRNPs complex and ribosome biogenesis. During assembly of the H/ACA snoRNPs complex, it associates with the complex, disappearing during maturation of the complex and being replaced by Gar1 to yield mature H/ACA snoRNPs complex. The core domain of Naf1 is homologous to the core domain of Gar1, suggesting that they share a common Cbf5 binding surface [].
H/ACA ribonucleoprotein particles (RNPs) are a family of RNA pseudouridine synthases that specify modification sites through guide RNAs. The function of these H/ACA RNPs is essential for biogenesis of the ribosome, splicing of precursor mRNAs (pre-mRNAs), maintenance of telomeres and probably for additional cellular processes []. All H/ACA RNPs contain a specific RNA component (snoRNA or scaRNA) and at least four proteins common to all such particles: Cbf5, Gar1, Nhp2 and Nop10. These proteins are highly conserved from yeast to mammals and homologues are also present in archaea []. The H/ACA protein complex contains a stable core composed of Cbf5 and Nop10, to which Gar1 and Nhp2 subsequently bind [].Naf1 is an RNA-binding protein required for the maturation of box H/ACA snoRNPs complex and ribosome biogenesis. During assembly of the H/ACA snoRNPs complex, it associates with the complex, disappearing during maturation of the complex and being replaced by Gar1 to yield mature H/ACA snoRNPs complex. The core domain of Naf1 is homologous to the core domain of Gar1, suggesting that they share a common Cbf5 binding surface [].
Ribosomes are the particles that catalyse mRNA-directed protein synthesis in all organisms. The codons of the mRNA are exposed on the ribosome to allow tRNA binding. This leads to the incorporation of amino acids into the growing polypeptide chain in accordance with the genetic information. Incoming amino acid monomers enter the ribosomal A site in the form of aminoacyl-tRNAs complexed with elongation factor Tu (EF-Tu) and GTP. The growing polypeptide chain, situated in the P site as peptidyl-tRNA, is then transferred to aminoacyl-tRNA and the new peptidyl-tRNA, extended by one residue, is translocated to the P site with the aid the elongation factor G (EF-G) and GTP as the deacylated tRNA is released from the ribosome through one or more exit sites [, ]. About 2/3 of the mass of the ribosome consists of RNA and 1/3 of protein. The proteins are named in accordance with the subunit of the ribosome which they belong to - the small (S1 to S31) and the large (L1 to L44). Usually they decorate the rRNA cores of the subunits. Many ribosomal proteins, particularly those of the large subunit, are composed of a globular, surfaced-exposed domain with long finger-like projections that extend into the rRNA core to stabilise its structure. Most of the proteins interact with multiple RNA elements, often from different domains. In the large subunit, about 1/3 of the 23S rRNA nucleotides are at least in van der Waal's contact with protein, and L22 interacts with all six domains of the 23S rRNA. Proteins S4 and S7, which initiate assembly of the 16S rRNA, are located at junctions of five and four RNA helices, respectively. In this way proteins serve to organise and stabilise the rRNA tertiary structure. While the crucial activities of decoding and peptide transfer are RNA based, proteins play an active role in functions that may have evolved to streamline the process of protein synthesis. In addition to their function in the ribosome, many ribosomal proteins have some function 'outside' the ribosome [, ].The genomic structure and sequence of the human ribosomal protein L7a has been determined and shown to resemble other mammalian ribosomal protein genes []. The sequence of a gene for ribosomal protein L4 of yeast has also been determined; its single open reading frame is highly similarto mammalian ribosomal protein L7a [, ]. Several other ribosomal proteins have been found to share sequence similarity with L7a, including Saccharomyces cerevisiae NHP2 [], Bacillus subtilis hypothetical protein ylxQ, Haloarcula marismortui Hs6, and Methanocaldococcus jannaschii (Methanococcus jannaschii) MJ1203.
Ribosomes are the particles that catalyse mRNA-directed protein synthesis in all organisms. The codons of the mRNA are exposed on the ribosome to allow tRNA binding. This leads to the incorporation of amino acids into the growing polypeptide chain in accordance with the genetic information. Incoming amino acid monomers enter the ribosomal A site in the form of aminoacyl-tRNAs complexed with elongation factor Tu (EF-Tu) and GTP. The growing polypeptide chain, situated in the P site as peptidyl-tRNA, is then transferred to aminoacyl-tRNA and the new peptidyl-tRNA, extended by one residue, is translocated to the P site with the aid the elongation factor G (EF-G) and GTP as the deacylated tRNA is released from the ribosome through one or more exit sites [, ]. About 2/3 of the mass of the ribosome consists of RNA and 1/3 of protein. The proteins are named in accordance with the subunit of the ribosome which they belong to - the small (S1 to S31) and the large (L1 to L44). Usually they decorate the rRNA cores of the subunits. Many ribosomal proteins, particularly those of the large subunit, are composed of a globular, surfaced-exposed domain with long finger-like projections that extend into the rRNA core to stabilise its structure. Most of the proteins interact with multiple RNA elements, often from different domains. In the large subunit, about 1/3 of the 23S rRNA nucleotides are at least in van der Waal's contact with protein, and L22 interacts with all six domains of the 23S rRNA. Proteins S4 and S7, which initiate assembly of the 16S rRNA, are located at junctions of five and four RNA helices, respectively. In this way proteins serve to organise and stabilise the rRNA tertiary structure. While the crucial activities of decoding and peptide transfer are RNA based, proteins play an active role in functions that may have evolved to streamline the process of protein synthesis. In addition to their function in the ribosome, many ribosomal proteins have some function 'outside' the ribosome [, ].The sequence of the acidic ribosomal protein S6 from Haloarcula marismortui has been determined []. The protein consists of 116 amino acid residues, and has a molecular mass of 12,251kDa. Sequence comparison with ribosomal proteins of other organisms has revealed that H. marismortui protein S6 is similar to mammalian protein L7a [], yeast L4 [], yeast NHP2 [], Bacillus subtilis hypothetical protein ylxQ and Methanocaldococcus jannaschii (Methanococcus jannaschii).
Ribosomes are the particles that catalyse mRNA-directed protein synthesis in all organisms. The codons of the mRNA are exposed on the ribosome to allow tRNA binding. This leads to the incorporation of amino acids into the growing polypeptide chain in accordance with the genetic information. Incoming amino acid monomers enter the ribosomal A site in the form of aminoacyl-tRNAs complexed with elongation factor Tu (EF-Tu) and GTP. The growing polypeptide chain, situated in the P site as peptidyl-tRNA, is then transferred to aminoacyl-tRNA and the new peptidyl-tRNA, extended by one residue, is translocated to the P site with the aid the elongation factor G (EF-G) and GTP as the deacylated tRNA is released from the ribosome through one or more exit sites [, ]. About 2/3 of the mass of the ribosome consists of RNA and 1/3 of protein. The proteins are named in accordance with the subunit of the ribosome which they belong to - the small (S1 to S31) and the large (L1 to L44). Usually they decorate the rRNA cores of the subunits. Many ribosomal proteins, particularly those of the large subunit, are composed of a globular, surfaced-exposed domain with long finger-like projections that extend into the rRNA core to stabilise its structure. Most of the proteins interact with multiple RNA elements, often from different domains. In the large subunit, about 1/3 of the 23S rRNA nucleotides are at least in van der Waal's contact with protein, and L22 interacts with all six domains of the 23S rRNA. Proteins S4 and S7, which initiate assembly of the 16S rRNA, are located at junctions of five and four RNA helices, respectively. In this way proteins serve to organise and stabilise the rRNA tertiary structure. While the crucial activities of decoding and peptide transfer are RNA based, proteins play an active role in functions that may have evolved to streamline the process of protein synthesis. In addition to their function in the ribosome, many ribosomal proteins have some function 'outside' the ribosome [, ].The genomic structure and sequence of the human ribosomal protein L7a has been determined and shown to resemble other mammalian ribosomal protein genes []. The sequence of a gene for ribosomal protein L4 of yeast has also been determined; its single open reading frame is highly similarto mammalian ribosomal protein L7a [, ]. Several other ribosomal proteins have been found to share sequence similarity with L7a, including Saccharomyces cerevisiae NHP2 [], Bacillus subtilis hypothetical protein ylxQ, Haloarcula marismortui Hs6, and Methanocaldococcus jannaschii (Methanococcus jannaschii) MJ1203.
Ribosomes are the particles that catalyse mRNA-directed protein synthesis in all organisms. The codons of the mRNA are exposed on the ribosome to allow tRNA binding. This leads to the incorporation of amino acids into the growing polypeptide chain in accordance with the genetic information. Incoming amino acid monomers enter the ribosomal A site in the form of aminoacyl-tRNAs complexed with elongation factor Tu (EF-Tu) and GTP. The growing polypeptide chain, situated in the P site as peptidyl-tRNA, is then transferred to aminoacyl-tRNA and the new peptidyl-tRNA, extended by one residue, is translocated to the P site with the aid the elongation factor G (EF-G) and GTP as the deacylated tRNA is released from the ribosome through one or more exit sites [, ]. About 2/3 of the mass of the ribosome consists of RNA and 1/3 of protein. The proteins are named in accordance with the subunit of the ribosome which they belong to - the small (S1 to S31) and the large (L1 to L44). Usually they decorate therRNA cores of the subunits. Many ribosomal proteins, particularly those of the large subunit, are composed of a globular, surfaced-exposed domain with long finger-like projections that extend into the rRNA core to stabilise its structure. Most of the proteins interact with multiple RNA elements, often from different domains. In the large subunit, about 1/3 of the 23S rRNA nucleotides are at least in van der Waal's contact with protein, and L22 interacts with all six domains of the 23S rRNA. Proteins S4 and S7, which initiate assembly of the 16S rRNA, are located at junctions of five and four RNA helices, respectively. In this way proteins serve to organise and stabilise the rRNA tertiary structure. While the crucial activities of decoding and peptide transfer are RNA based, proteins play an active role in functions that may have evolved to streamline the process of protein synthesis. In addition to their function in the ribosome, many ribosomal proteins have some function 'outside' the ribosome [, ].The genomic structure and sequence of the human ribosomal protein L7a has been determined []. The gene contains 8 exons and 7 introns, encompassing 3179 bp. The human gene resembles other mammalian ribosomal protein genes in so far as it contains a short first exon, a short 5' untranslated leader and its transcriptional start sites at C residues embedded in a poly-pyrimidine tract [].The sequence of a gene for ribosomal protein L4 of Saccharomyces cerevisiae (Baker's yeast) has also been determined, which, unlike most of its other ribosomal protein genes, has no intron []. The single open reading frame is highly similar to mammalian ribosomal protein L7a.There appear to be two genes for L4, both ofwhich are active []. Yeast cells containing a disruption of the L4-1 gene form smaller colonies than either wild-type or disrupted L4-2 strains. Disruption of both L4 genes is lethal, probably resulting from an inability of the organism to produce functional ribosomes [].Several other ribosomal proteins have been found to share sequence similarity with L7a, including yeast NHP2 [], Bacillus subtilis hypothetical protein ylxQ, Haloarcula marismortui (Halobacterium marismortui) Hs6, and Methanocaldococcus jannaschii MJ1203.This InterPro entry focus on regions that characterise the ribosomal L7A proteins but distinguish them from the rest of the HMG-like family.
