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Heterogeneous nuclear ribonucleoprotein A1 (HNRNPA1) is a member of the A/B subfamily of ubiquitously expressed heterogeneous nuclear ribonucleoproteins (hnRNPs). HNRNPA1 is involved in the packing of pre-mRNA into hnRNP particles, transport of poly(A) mRNA from the nucleus to the cytoplasm and may control splice site selection. The HNRNPA1 protein may also have a role in HCV RNA replication. In addition, HNRNPA1 is believed to have a key role in the formation of specific myometrial protein species in parturition.
The hnRNP proteins have distinctive nucleic acid binding properties. HNRNPA1 has 2 repeats of quasi-RRM domains that bind to RNAs. HNRNPA1 is one of the most copious core proteins of hnRNP complexes and it is restricted to the nucleoplasm. The HNRNPA1 protein, along with other hnRNP proteins, is exported from the nucleus, most likely bound to mRNA, and is immediately re-imported. The M9 domain of HNRNPA1 functions as both a nuclear localization and nuclear export signal.

Rnase P protein, AKA rnpA, is an important enzyme consisting of the C5 protein (which encoded by rnpA) and the catalytic M1 RNA (encoded by rnpB) subunits. rnpA is ribonucleoprotein that catalyzes the removal of the 50- leader elements of precursor tRNAs and generates the mature 50-end of tRNAs. This step is critical for theformation of functional tRNA molecules in bacteria, archaea and eukarya. More importantly, it has lately been established that RNase P is essential for the endonucleolytic separation of certain polycistronic tRNA transcripts such as valV valW, leuQ leuP leuV and secG leuU. Therefore, it was hypothesized that the essential function of RNase P might be related to the complete absence of a particular tRNAthat was dependent on the enzyme for initial separation from polycistronic transcripts.

EMG1 is a 244 aa protein which has a role in ribosome biogenesis. EMG1 is a key protein in the small ribosomal subunit assembly, controls methylation during ribosome synthesis and takes part in pre-18S rRNA processing. EMG1 is localized to the nucleolus and a mutation in this gene is linked with Bowen-Conradi syndrome.

RNA binding motif protein 17 (RBM17) is a splice factor which binds to the single stranded 3'AG at the exon/intron border and promotes its utilization in the 2nd catalytic step. The RBM17 protein is involved in the regulation of alternative splicing and the utilization of cryptic splice sites. RBM17 protein also stimulates the utilization of a cryptic splice site created by the beta-110 mutation in the HBB gene. The ensuing frameshift leads to sickle cell anemia.

CTD small phosphatase-like protein (CTDSPL) specially catalyzes the dephosphorylation of 'Ser-5' within the tandem 7 residues repeats in the C-terminal domain (CTD) of the biggest RNA polymerase II subunit POLR2A. CTDSPL negatively regulates RNA polymerase II transcription, probably by directing the transition from initiation/capping to processive transcript elongation. CTDSPL is employed by REST to neuronal genes which contain RE-1 elements, directing to neuronal gene silencing in non-neuronal cells.

Ribonuclease 1R (NASE1) is a small protein which is a part of pancreatic ribonuclease enzyme family. NASE1 has 4 disulfide bonds in its native state and cleaves speciallyafter pyrimidine nucleotides.Cleavage takes place in 2 steps: first, the 3’,5’-phosphodiester bond is cleaved to craete a 2’,3’-cyclic phosphodiester intermediate; than, the cyclic phosphodiester is hydrolyzed to a 3’-monophosphate. NASE1is activated the most with single stranded RNA.NASE1inhibited by alkylation of His12 and His119 and activated by potassium and sodium salts.NASE1hydrolyzes RNA from protein samples.

Ribophorin 2 (RPN2) is a dolichyl-diphosphooligosaccharide protein glycosyltransferase subunit 2. The Ribophorin 2 protein is part of an N-oligosaccharyl transferase complex which links high mannose oligosaccharides to asparagine residues found in the Asn-X-Ser/Thr consensus motif of nascent polypeptide chains. RPN2 is analogous in sequence to the yeast oligosaccharyl transferase subunit SWP1.

7-methylguanosine phosphate-specific 5'-nucleotidase (NT5C3B) includes transferase activity and nucleotide binding. Among NT5C3B’s related super-pathways are adenosine nucleotides degradation II and Pyrimidine metabolism. NT5C3B hydrolyzes 7-methylguanosine monophosphate (m(7)GMP) to 7-methylguanosine and inorganic phosphate. The specific activity for m(7)GMP guards cells against undesired retrieval of m(7)GMP and its incorporation into nucleic acids. In addition, NT5C3B has weak activity for CMP.

Mitochondrial methylglutaconyl-CoA hydratase (AUH) is involved in the amino acid degradation pathway by catalyzing the conversion of 3-methylglutaconyl-CoA to 3-hydroxy-3-methylglutaryl-CoA and water. AUH Human is expressed as a single mRNA species of 1.8 kb, and translated as a 40kDa precursor protein which is consequently processed to a 32kDa mature form. AUH has a very low enoyl-CoA hydratase activity. The AUH protein binds to the AU-rich element (ARE), which is a common element found in the 3' UTR of rapidly decaying mRNA such as c-fos, c-myc and granulocyte/ macrophage colony stimulating factor. AU-rich elements are involved in directing RNA to rapid degradation and deadenylation. In addition, AUH is homologous to enol-CoA hydratase, which is an enzyme involved in fatty acid degradation, and has been shown to have intrinsic hydratase enzymatic activity. AUH is therefore a bifunctional chimera between RNA binding and metabolic enzyme activity.

Elongin B (Elob) is a subunit of the transcription factor B (SIII) complex. SIII complex is a general transcription elongation factor that increases the RNA polymerase II transcription elongation past template-encoded arresting sites. The SIII complex comprised of a transcriptionally active subunit (A) and 2 regulatory subunits (B and C). Subunit A is transcriptionally active and its transcription activity is enhanced by binding to the dimeric complex of the SIII regulatory subunits B and C. The von Hippel-Lindau tumor suppressor protein binds to elongin B and C and inhibits transcription elongation.

BAT1 belongs to the DEAD box family of RNA-dependent ATPases that mediate ATP hydrolysis during pre-mRNA splicing. UAP56 protein is a vital splicing factor which is needed for connecting U2 small nuclear ribonucleoprotein with pre-mRNA, as well as takes a key part in mRNA export from the nucleus to the cytoplasm. Mutations in this protein may be connected to rheumatoid arthritis.

Mediator complex subunit 4 (MED4) is a component of the Mediator complex, a coactivator involved in the regulated transcription of nearly all RNA polymerase II-dependent genes. MED4 is a component of the vitamin D receptor-interacting protein (DRIP) complex which functions as a nuclear receptor coactivator. The DRIP complex is able to activate nuclear receptors in a ligand-dependent manner. MED4 functions as a link to convey information from gene-specific regulatory proteins to the basal RNA polymerase II transcription apparatus. MED4 is recruited to promoters by direct interactions with regulatory proteins and serves as a scaffold for the assembly of a functional preinitiation complex with RNA polymerase II and the general transcription factors.

Single-strand-selective monofunctional uracil-DNA glycosylase (SMUG1) is an enzyme responsible for recognizing base lesions in the genome and initiating base excision DNA repair. SMUG1 participates in base excision repair by removing uracil from single- and double-stranded DNA. SMUG1 serves as a monofunctional DNA glycosylase specific for uracil (U) residues in DNA and has inclination for single-stranded DNA substrates. SMUG1 activity is greater against mismatches (U/G) than against matches (U/A).

SNUPN is a nuclear import adaptor protein which is part of the Snurportin family.
SNUPN is Localized to the cytoplasm and nucleus and contains an N-terminal IBB domain and a trimethylguanosine (m3G)-cap binding domain. SNUPN binds specifically the terminal 2,2,7-m3G-cap at the 5'' end of U snRNPs and is involved in transport of U snRNPs into the nucleus through an association with Importin β.

DIM1 dimethyladenosine transferase 1 homolog (DIMT1) is a member of the methyltransferase superfamily. The DIMT1 enzyme specifically dimethylates 2 adjacent adenosines in the loop of a conserved hairpin near the 3'-end of 18S rRNA in the 40S particle. DIMT1 is restricted to the nucleolus.

FBL is a significant small nucleolar protein in eukaryotes, which has an essential role in pre-rRNA processing during ribosomal biogenesis. Fibrillarin is a component of several ribonucleoproteins including a nucleolar small nuclear ribonucleoprotein (SnRNP) and one of the two classes of small nucleolar ribonucleoproteins (snoRNPs). Fibrillarin contains an N-terminal repetitive domain which is rich in glycine and arginine residues, like fibrillarins in other species. Fibrillarin’s central region is similar to an RNA-binding domain and contains an RNP consensus sequence. FBL is linked to the U3, U8, and U13 small nuclear RNAs and is positioned in the dense fibrillar component (DFC) of the nucleolus. Antisera from roughly 8% of humans with the autoimmune disease scleroderma recognize fibrillarin.

DNA-3-methyladenine glycosylase (MPG) is a member of the DNA glycosylase MPG family. MPG initiates base excision repair in DNA by removing a wide variety of alkylated, deaminated, and lipid peroxidation-induced purine adducts.

EXO2 is a 3'-to-5' exonuclease specific for small (primarily 5 nucleotides or less in length) single-stranded RNA and DNA oligomers. RNA Exonuclease 2 (REXO2) takes part in DNA repair, replication, and recombination, and in RNA processing and degradation. EXO2 is involved in resistance of human cells to UV-C-induced cell death via its part in the DNA repair process.

Alanyl-tRNA synthetase is a member of the aminoacyl-tRNA synthetase family, key enzymes of protein biosynthesis which charge tRNA molecules with the respective amino acids. This 108 kDa protein is an autoantigen recognized by PL-12 antibodies which occur in a subset of patients with polymyositis and dermatomyositis. Preliminary data suggest that epitope spreading occurs in the autoimmune PL-12 response such that even antibodies to an isolated alanyl-tRNA molecule can develop.

Ribonuclease 7 (RNASE7) is one of the final RNase A superfamily ribonucleases. RNASE7 was isolated from skin-derived stratum corneum. RNASE7 protein demonstrated potent ribonuclease activity and hence may contribute to the well-known ribonuclease activity of human skin. RNASE7 has revealed a broad spectrum antimicrobial activity against many pathogenic microorganisms and extraordinarily potent activity.

Streptavidin is a tetrameric protein secreted by Streptomyces avidinii which binds firmly to biotin. Streptavidin is widely used in molecular biology through its unique high affinity for the vitamin biotin. The dissociation constant (Kd) of the biotin-streptavidin complex is about ~10-15 mol/L. The strong affinity recognition of biotin and biotinylated molecules has made streptavidin one of the most important components in diagnostics and laboratory kits. The streptavidin/biotin system has one of the biggest free energies of association of yet observed for noncovalent binding of a protein and small ligand in aqueous solution (K_assoc = 10**14). The complexes are also extremely stable over a wide range of temperature and pH.

FtsJ RNA Methyltransferase Homolog 2 (FTSJ2) belongs to the S-adenosylmethionine-binding protein family. FTSJ2 is a nucleolar protein and which is involved in cell cycle control and DNA repair and the processing and modification of rRNA. FTSJ2 is extensively expressed, with the highest expression in the muscle, placenta, and heart.

Small nuclear ribonucleoprotein polypeptide G (SNRPG) is a member of the snRNP Sm proteins family. There are at least 7 isoforms, B/B, E, F, G, D1, D2, and D3. This class of common proteins has a vital role in the biogenesis of the snRNPs. The human Sm G genes are mapped to chromosomes 2. Furthermore, these proteins represent the major targets for the supposed anti-Sm auto-antibodies which are diagnostic for SLE (systemic lupus erythematosus). One class of these autoantibodies reacts specifically with native Sm E-F-G complexes.

RNA Binding Motif Protein 11 (RBM11) which contains 1 RNA recognition motif is a part of the RBM family. The RBM gene family encodes proteins with an RNA binding motif which participate in the modulation of apoptosis. RBM11 is expressed in testis, kidney, spleen, brain, spinal cord and mammary gland and can be found as 2 isoforms produced by alternative splicing.