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SNRPE facilitates the cytoplasmic construction of the UsnRNPs by binding to a conserved Sm site on UsnRNA and forming a stable snRNP core complex. While a core protein to UsnRNP, the SNRPE connects with the entire U family of snRNAs including U1–U6. In addition, SNRPE interacts with DDX20 and Small nuclear ribonucleoprotein polypeptide F.

Nucleosome Assembly Protein 1-Like 4 (NAP1L4) is a part of the nucleosome assembly protein (NAP) family which interacts with both core and linker histones. NAP1L4 plays a role as a histone chaperone due to his ability to shuttle between the cytoplasm and nucleus. NAP1L4 modulates transcriptional activation by target nuclear receptors. NAP1L4 is one of several located near the imprinted gene domain of 11p15.5 which is an important tumor-suppressor gene region.

DDX39A which is a part of the DEAD box protein family is characterized by the conserved motif Asp-Glu-Ala-Asp. This pattern is implicated in a various cellular processes involving alteration of RNA secondary structure, nuclear and mitochondrial splicing, and ribosome and spliceosome assembly. Several members of the DEAD box protein family are taking part in embryogenesis, spermatogenesis, and cellular growth and division.

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.

RNA Guanylyltransferase And 5'-Phosphatase also known as RNGTT is a bifunctional mRNA-capping enzyme which exhibits RNA 5'-triphosphatase activity in the N-terminal section and mRNA guanylyltransferase activity in the C-terminal section. In addition, RNGTT catalyzes the first two steps of cap formation, through removing the gamma-phosphate from the 5'-triphosphate end of nascent mRNA to yield a diphosphate end, and also by transferring the gmp moiety of GTP to the 5'-diphosphate terminus.

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.

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.

SNRPC is a member of the U1 small nuclear ribonucleoprotein C family. The SNRPC protein component of the U1 small nuclear ribonucleoprotein (snRNP) particle required for the formation of the spliceosome. SNRPC participates in the processing of nuclear precursor messenger RNA splicing. snRNP particles are tackled by autoantibodies frequently produced by patients with connective tissue diseases.

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.

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.

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.

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.

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.

Ribonuclease P protein subunit p30 (RPP30) is a member of the eukaryotic/archaeal RNase P protein component 3 family. RPP30 is component of ribonuclease P, which is a protein complex that generates mature tRNA molecules by cleaving their 5'-ends. Ribonuclease P (RNase P) is small nuclear ribonucleoprotein (snRNPs) which acts on RNA substrates in vitro. In addition, RNase P which accumulate in the nucleolus, have a similar RNA component and several protein subunits in common.

Polyribonucleotide nucleotidyltransferase 1, also known as PNPT1 is predominantly localized in the mitochondrial intermembrane space and is implicated in the import of RNA to mitochondria. Mutations in PNPT1 have been connected with combined oxidative phosphorylation deficiency-13 as well as autosomal recessive nonsyndromic deafness-70. Related pseudogenes have been found on chromosomes 3 & 7.

APOBEC4 belongs to the AID/APOBEC family of polynucleotide (deoxy)cytidine deaminases, which convert cytidine to uridine. Further AID/APOBEC family members are implicated in Mrna editing, somatic hypermutation and recombination of immunoglobulin genes, and innate immunity to retroviral infection. Among the diseases associated with APOBEC4 are systemic lupus erythematosus, and lupus erythematosus.

Polypeptide N-Acetylgalactosaminyltransferase 1 (Galnt1) is a part of the UDP-N-acetyl-alpha-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase (GalNAc-T) family of enzymes. The initial reaction in O-linked oligosaccharide biosynthesis is catalyzed by Glant1, the transfer of an N-acetyl-D-galactosamine residue to a serine or threonine residue on the protein receptor. Moreover, Galnt1 is implicated in the glycosylation of proteins vital for bone formation for instance osteopontin and bone sialoprotein.

Heterogeneous Nuclear Ribonucleoprotein A/B (HNRNPAB) is a member of the subfamily of ubiquitously expressed heterogeneous nuclearribonucleoproteins (hnRNPs). The hnRNPs are produced by RNA polymerase II and are components of theheterogeneous nuclear RNA (hnRNA) complexes. They are linked with pre-mRNAs in the nucleus and seem to influence pre-mRNA processing and further aspects of mRNA metabolism and transport. Whereas all of the hnRNPsare present in the nucleus, some seem to shuttle between the nucleus and the cytoplasm. The hnRNP proteins have distinct nucleic acid binding properties. HNRNPAB, which binds to one of the components of the multiproteineditosome complex, has two repeats of quasi-RRM (RNA recognition motif) domains that bind to RNAs. Among the diseases associated with HNRNPAB are wells syndrome, and cystic fibrosis.

RNHA is an endonuclease which specifically degrades the RNA of RNA-DNA hybrids. Localized to the nucleus, the RNHA protein mediates the removal of Okazaki fragment RNA primers which are present on the lagging strand during DNA replication. RNHA catalyzes the endonucleolytic cleavage of RNA to a 5'-phosphomonoester and is capable of binding magnesium or manganese as cofactors.

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.

Ribonuclease 3 (RNASE3) is cytotoxin and helminthotoxin with low-efficiency ribonuclease activity. RNASE3 possesses a broad diversity of biological activities. RNASE3 protein has shown antibacterial activity such as cytoplasmic membrane depolarization of preferentially Gram-negative and Gram-positive strains and promotes E. coli outer membrane detachment, alteration of the overall cell shape and partial loss of cell content.

POU5F1 is a homeodomain transcription factor of the POU family, expressed in embryonic stem (ES) cells and embryonic carcinoma (EC) cells.POU5F1 is significantly involved in the signaling pathway for maintaining self-renewal and pluripotency of ES cells. POU5F1 has 2 distinct DNA binding domains which independently bind half-sites of the canonical octamer motif. This flexibility allows POU5F1 to bind with distinct DNA motifs by forming heterodimers with other transcription factors or by forming homodimers in several conformations. Human POU5F1 contains a 75aa POU specific (POUS) domain and a 60aa POU-Homeo-(POUH) domain connected by a linker region. The Human POU5F1 specifically interacts with Octamer motif ATGCAAAT. In addition, 2 proline-rich domains in the N-terminal and C-terminal regions are vital for POU5F1 transactivation. POU5F1 regulates a number of target genes and has been shown to work jointly with other transcription factors including Sox2 as well as Nanog to sustain stem cell potency and self-renewal.

rRNA-processing protein UTP23 homolog (UTP23) is a small subunit (SSU) processome component. The SSU processome is a complex involved in ribosome biogenesis and essential for pre-18S rRNA maturation. UTP23 is vital for the first 3 cleavage steps in 18S rRNA maturation. Furthermore, single-point mutations in the conserved putative active site of Utp24 but not Utp23 annul its function in ribosome biogenesis.

TSR2 is part of the TSR2 family. TSR2 is involved in 20S pre-rRNA processing. Among the diseases which are associated with TSR2 are blepharospasm and diamond-blackfan anemia.