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SARS Coronavirus is an enveloped virus containing three outer structural proteins, namely the membrane (M), envelope (E), and spike (S) proteins. Spike (S)-glycoprotein of the virus interacts with a cellular receptor and mediates membrane fusion to allow viral entry into susceptible target cells. Accordingly, S-protein plays an important role in virus infection cycle and is the primary target of neutralizing antibodies.
It has recently been shown that SARS (severe acute respiratory syndrome) is caused by a human coronavirus. Human coronaviruses are the major cause of upper respiratory tract illness, such as the common cold, in humans. Coronaviruses are positive-stranded RNA viruses, featuring the largest viral RNA genomes known to date (27-31 kb). The first step in coronavirus infection is binding of the viral spike protein, a 139-kDa protein, to certain receptors on host cells. The spike protein is the main surface antigen of the coronavirus. The glycosilated spike protein (as well as the nucleocapsid protein) can be detected in infected cell culture supernatants with antisera from SARS patients.

S100A11 is a member of the S100 family of proteins which contains two EF-hand calcium-binding motifs and is thought to be involved in the regulation of a number of cellular processes including cell cycle progression and differentiation. S100A11 may function in motility, invasion and tubulin polymerisation. S100 proteins are localized either in the cytoplasm or the nucleus of a wide range of cells. There are at least 13 members in the S100 gene family, which are located as a cluster on chromosome 1q21. Chromosomal rearrangements and altered expression of S100A11 have been implicated in tumor metastasis.

Cystatin 11 (CST11) is a member of the Cystatin family. The Cystatin superfamily is comprised of proteins with multiple cystatin-like sequences. Several family members are active cysteine protease inhibitors, other family members have lost or perhaps never developed this inhibitory activity. The Cystatin superfamily consists of three inhibitory families, including the type 1 cystatins (stefins), type 2 cystatins and the kininogens. The type 2 cystatin proteins are a class of cysteine proteinase inhibitors found in a variety of human fluids and secretions. The majority of the type 2 cystatin genes and pseudogenes are contained in the cystatin locus on chromosome 20. CST11 is located in the cystatin locus and encodes an epididymal-specific protein whose specific function has not been verified yet.

Heterogeneous Nuclear Ribonucleoprotein K, also known as HNRNPK, is a part of the subfamily of ubiquitously expressed heterogeneous nuclear ribonucleoproteins (hnRNPs). HNRNPK takes part in p53/TP53 reaction to DNA damage, acting at the level of both transcription activation and repression. HNRNPK is located in the nucleoplasm and has 3 repeats of KH domains which bind to RNAs.

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.

GDF-11 belongs to the bone morphogenetic protein (BMP) family and the TGF-beta superfamily. GDF-11 is a central developmental factor which controls muscular and neural development. In adults, GDF-11 encourages cardiac hypertrophy reverse by the revival of cardiomyocytes.

IFN-tau is also known as TP-1 (trophoblast protein-1) is a new class of type I IFN that is secreted by the trophoblast and is the signal for maternal recognition of pregnancy in sheep. IFN- tau has potent immunosuppressive and antiviral activities similar to other type I IFN but is less cytotoxic than IFN-alpha and IFN-beta. The current investigation concerns the effect of recombinant ovine IFN- tau (rOIFN- tau) on the modulation of MHC class I and II expression on cloned mouse cerebrovascular endothelial (CVE) cells.
IFN-tau induced tyrosine phosphorylation of Stat1 and upregulated the expression of MHC class I on CVE. One proposed action by which type I IFN reduces the relapse rate in MS is via interference with IFN-?-induced MHC class II expression. IFN- tau was shown to downregulate IFN-?-induced MHC class II expression on CVE and, hence, may be of potential therapeutic value in downregulating inflammation in the central nervous system (CNS). IFN- tau did not upregulate the expression of MHC class II on CVE. IFN- tau also inhibited the replication of Theiler's virus in CVE.

Decorin (DCN) is a small cellular or pericellular matrix proteoglycan which is closely related in structure to biglycan protein. Decorin is a secreted protein which binds to collagen and fibronectin in extracellular matrix. Decorin appears in different glycoforms, substituted with chondroitin sulfate or dermatan sulfate consistent with the original tissue. DCN contains one attached glycosaminoglycan chain. Decorin influences the rate of fibril formation. Decorin is capable of suppressing the growth of various tumor cell lines. DCN gene defects cause corneal dystrophy. The DCN gene is a candidate gene for Marfan syndrome.

PDZ Domain Containing 11 (PDZD11) is a cytosolic protein which contains one PDZ (DHR) domain. PDZD11 displays a resemblance to members of the MALS / VELIS family of proteins. PDZD11 contains but one PDZ domain which seemingly interacts with the C-terminus of partner proteins. PDZD11 is ubiquitously expressed and targets calcium and copper ATPases to basolateral cell membranes. PDZD11 is a briefly interacting partner of the PMCA b-splice forms which have a role in their sorting to or from the plasma membrane.

Carbonic anhydrases (CAs) are a large family of zinc metalloenzymes which catalyze the reversible hydration of carbon dioxide. These metalloenzymes participate in various biological processes, including respiration, calcification, acid-base balance, bone resorption, and the formation of aqueous humor, cerebrospinal fluid, saliva, and gastric acid. The metalloenzymes exhibit extensive diversity in tissue distribution and in their subcellular localization. Carbonic Anhydrase XI (CA11) is probably a secreted protein, nevertheless, drastic changes at active site residues completely conserved in CA isozymes with catalytic activity, make it unlikely that CA11 has carbonic anhydrase activity. CA11 shares properties in common with 2 other acatalytic CA isoforms, CA VIII and CA X. CA11 is amply expressed in the brain, and may have a general role in the central nervous system.

UCN119B is a member of the PDE6D/unc-119 family. UCN119B has a large number of photoreceptors of the retina. Additionaly, UCN119B has a strong homology with the C. elegans unc119 and is able to functionally complement the C. elegans unc119 mutation gene.

Matrix metalloproteinase-14 (MMP14), is a membrane-anchored zinc-binding endopeptidase which is expressed at the leading edge of different invasive carcinomas and also promotes tumor cell invasion through degradation of the extracellular matrix. MMP14 takes a vital part in extracellular matrix, ECM, remodeling by having the capability to degrade type I collagen, activate pro-MMP-2 and process cell adhesion molecules for instance CD44 and integrin alpha V. MMP14 is a key enzyme in many physiological as well as pathological processes for example angiogenesis & tumor invasion.

Streptavidin is a tetrameric protein secreted by Streptomyces avidinii which binds firmly to biotin. Streptavidin is wilyde 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.

NusA is an important player in both prevention and enhancement of transcriptional termination. NusA is important both in Rho-dependent and intrinsic termination, as well as in lambda and other phage antitermination systems. The NusA gene was first identified by isolation of the nusAl mutation, which limits bacteriophage-l growth by preventing the antitermination activity of the l N protein. NusA plays a role in transcriptional antitermination in the cell. It has been shown to specifically aid in read-through of the RNA polymerase genes rpoB and rpoC, as well as in successful synthesis of the ribosomal RNA genes. Additionally to its anti-termination role, NusA is needed for both Rho-dependent and intrinsic transcriptional termination. NusA is obligatory for Rho-dependent termination in lambda phage and in the cell. NusA plays a role in intrinsic termination and the inhibition of RNA elongation. However NusA interacts with all three subunits of RNA polymerase, its termination activity primarily depends on its interaction with the carboxy-terminus of RpoA. NusA induces conformational change in RNA polymerase & prevents RNA interaction with RpoA. This binding sequentially activates NusA, allowing it to bind RNA and promote formation of hairpins at intrinsic termination sites. NusA binds Rho, and participates with sigma70 for binding to the core RNA polymerase complex. NusA does not compete with NusG for binding to either Rho or the polymerase, despite modulating the same process as NusG in both cases.

Yersinia enterocolitica is a Gram-negative bacillus-shaped bacterium, which is a member of the Enterobacteriaceae family. Y.Enterocolitica is motile at temperatures between 22-29°C, however becomes non-motile at normal human body temperature. Y. Enterocolitica infection causes the yersiniosis disease, which is an animal-borne disease occurring in humans, as well as in a various groups of animals such as cattle, deer, pigs, and birds. Yersinia enterocolitica is a heterogeneous group of strains, which are conventionally classified by bio-typing into six bio-groups on the basis of phenotypic characteristics, and by serotyping into more than 57 “O” serogroups, on the basis of their O (lipopolysaccharide or LPS) surface antigen. Five of the six biogroups (1B and 2–5) are considered as pathogens. Nevertheless, only a few of these serogroups have been linked with disease in either humans or animals. Strains which belong to serogroups O:3 (biogroup 4), O:5,27 (biogroups 2 and 3), O:8 (biogroup 1B), and O:9 (biogroup 2) are most frequently isolated worldwide from human samples. Still, the main Y. enterocolitica serogroup in many European countries is serogroup O:3 followed by O:9, whereas the serogroup O:8 is mostly detected in the United States.

Meteorin (METRN) is involved in both glial cell differentiation and axonal network formation during neurogenesis. METRN promotes astrocyte differentiation and transforms cerebellar astrocytes into radial glia. Moreover, the METRN protein stimulates axonal extension in small and intermediate neurons of sensory ganglia by activating nearby satellite glia.

Neuronal Regeneration Related Protein (NREP) has roles in neural function. NREP promotes axonal regeneration. In addition, NREP has functions in cellular differentiation. NREP protein induces differentiation of fibroblast into myofibroblast and increases retinoic-acid regulation of lipid-droplet biogenesis. NREP down-regulates the expression of TGFB1 and TGFB2 but not of TGFB3. NREP has a role in the regulation of alveolar generation.

Vascular endothelial growth factor is an important signaling protein involved in both vasculogenesis and angiogenesis. As its name implies, VEGF activity has been mostly studied on cells of the vascular endothelium, although it does have effects on a number of other cell types (e.g. stimulation monocyte/ macrophagemigration, neurons, cancer cells, kidney epithelial cells ).VEGF mediates increased vascular permeability, induces angiogenesis, vasculogenesis and endothelial cell growth, promotes cell migration, and inhibits apoptosis. In vitro, VEGF has been shown to stimulate endothelial cell mitogenesisand cell migration. VEGF is also a vasodilator and increases microvascular permeability and was originally referred to as vascular permeability factor.
Elevated levels of this protein are linked to POEMS syndrome, also known as Crow-Fukase syndrome. Mutations in this gene have been associated with proliferative and nonproliferative diabetic retinopathy.

Granulocyte/Macrophage Colony-Stimulating Factors are cytokines that act in hematopoiesis by controlling the production, differentiation, and function of 2 related white cell populations of the blood, the granulocytes and the monocytes-macrophages. CSF-1 induces cells of the monocyte/macrophage lineage. It plays a role in immunological defenses, bone metabolism, lipoproteins clearance, fertility and pregnancy.

Folate Receptor 1, also known as FOLR1, is a part of the folate receptor family whose members bind folic acid. FOLR1 binds to folate and reduced folic acid derivatives and facilitates transfer of 5-methyltetrahydrofolate and folate analogs into the cells. FOLR1 is either attaches to membranes through a glycosyl-phosphatidylinositol linkage or exists in a soluble form. FOLR1 is also needed for embryonic development and normal cell proliferation.

GDF-11 belongs to the bone morphogenetic protein (BMP) family and the TGF-beta superfamily. GDF-11 is a central developmental factor which controls muscular and neural development. In adults, GDF-11 encourages cardiac hypertrophy reverse by the revival of cardiomyocytes.

Human papillomaviruses (HPVs) are a group family with more than 150 related viruses. HP 6 and 11 considered as low-risk HPVs can be sexually transmitted, causing warts to emerge on or around the genitals or anus, known as condylomata acuminate. HPV 11 major/large capsid antigen is used in clinical diagnosis to test the specific antibody to this virus induced by the virus infection, the positive reaction of this antibody is deemed as a marker for present and past infection. Furthermore, HPV 11 large capsid is used as a potential candiadate for vaccine development.

Since April 2012, cases of the Middle East Respiratory Syndrome Coronavirus (MERS-CoV) have been identified in various countries. Coronaviruses are the cause of the common cold, SARS (severe acute respiratory syndrome) and other severe illnesses with high mortality rates, all are classified into coronavirus family. MERS-CoV is a new type of SARS found in the coronavirus family causing severe pneumonia with sudden and serious respiratory illness with high mortality rates as well. Since January 27th 2015, the WHO has reported 956 human cases, including 351 deaths. More cases of the new coronavirus strain are expected. Like in other coronaviruses, large surface spike glycoprotein is a central structural protein of this virus; it is located above the virion surface to bind and enter into the target cell. Spike protein has 2 domains- S1 and S2. The S1 domain is responsible for cellular tropism and interaction with target cell, while the S2 domain is responsible for membrane fusion. The C-terminal of S1 domain contains a receptor binding domain, and is also a potential target for vaccine development and an antigen for diagnosis.