Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.11.1 (protein kinase)
81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The DNA sequence (8.9 kb) covering about 70% of the short unique region (Us) and part of the short inverted repeat of the Marek's disease virus type 1 GA strain was determined. Computer analysis of the sequence showed the presence of nine potential open reading frames (ORFs), consisting of more than 300 nucleotides in the Us region. Of these ORFs, four were found to be homologous to US10 (minor virion protein), US3 (protein kinase), US2, and US6 (gD) in the Us region of alpha-herpesvirus herpes simplex virus type 1. The protein kinase homologue is especially well conserved in alpha-herpesviruses. No counterpart of the nine MDV1 ORFs was found in the beta-herpes virus human cytomegalovirus and gamma-herpesvirus Epstein-Barr virus, suggesting that MDV1 is more similar to the alpha-herpesviruses. The junction of the Us region and the short inverted repeat was also determined by comparison between the sequences of the DNA fragments, including the terminal and internal repeats. Northern blot analysis showed that the Us region within the 8.9 kb sequence was transcriptionally active in MDV1-infected cells.
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PMID:Sequence determination and genetic content of an 8.9-kb restriction fragment in the short unique region and the internal inverted repeat of Marek's disease virus type 1 DNA. 128 82

Expression of the Epstein-Barr virus (EBV) BZLF1 gene product ZEBRA is a first step in the cascade of the virus-productive cycle. ZEBRA protein was detected by immunoblotting as a single band at 38 kDa in Akata cells after crosslinkage of membrane immunoglobulin G (IgG) with anti-IgG antibody. Immunoprecipitation of [32P]phosphate-labeled, anti-IgG-stimulated Akata cells with anti-ZEBRA antibody showed that ZEBRA was phosphorylated. Phosphoamino acid analysis demonstrated phosphorylation of serine, but not threonine or tyrosine, and tryptic-peptide mapping showed multiple phosphorylated peptides of ZEBRA. Treatment with 8-bromo cAMP and blockage of phosphodiesterase by theophylline in anti-IgG-stimulated cells increased the phosphorylation of three ZEBRA peptides. Incubation with 12-O-tetradecanoylphorbol-13-acetate (TPA) reduced the phosphorylation of these three ZEBRA peptides, while treatment with staurosporine, a protein kinase C (PKC) inhibitor, enhanced their phosphorylations. These data suggest that activation of PKC with TPA induces the ZEBRA dephosphorylation and that activation of cAMP-dependent protein kinase A enhances the ZEBRA phosphorylation at the specific sites.
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PMID:Phosphorylation of the Epstein-Barr virus BZLF1 immediate-early gene product ZEBRA. 131 87

This report describes the complete nucleotide sequence of the genome of herpesvirus saimiri, the prototype of gammaherpesvirus subgroup 2 (rhadinoviruses). The unique low-G + C-content DNA region has 112,930 bp with an average base composition of 34.5% G + C and is flanked by about 35 noncoding high-G + C-content DNA repeats of 1,444 bp (70.8% G + C) in tandem orientation. We identified 76 major open reading frames and a set of seven U-RNA genes for a total of 83 potential genes. The genes are closely arranged, with only a few regions of sizable noncoding sequences. For 60 of the predicted proteins, homologous sequences are found in other herpesviruses. Genes conserved between herpesvirus saimiri and Epstein-Barr virus (gammaherpesvirus subgroup 1) show that their genomes are generally collinear, although conserved gene blocks are separated by unique genes that appear to determine the particular phenotype of these viruses. Several deduced protein sequences of herpesvirus saimiri without counterparts in most of the other sequenced herpesviruses exhibited significant homology with cellular proteins of known function. These include thymidylate synthase, dihydrofolate reductase, complement control proteins, the cell surface antigen CD59, cyclins, and G protein-coupled receptors. Searching for functional protein motifs revealed that the virus may encode a cytosine-specific methylase and a tyrosine-specific protein kinase. Several herpesvirus saimiri genes are potential candidates to cooperate with the gene for saimiri transformation-associated protein of subgroup A (STP-A) in T-lymphocyte growth stimulation.
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PMID:Primary structure of the herpesvirus saimiri genome. 132 Dec 87

A major in vivo phosphorylation site of the Epstein-Barr virus nuclear antigen 2 (EBNA-2) was found to be localized at the C-terminus of the protein. In vitro phosphorylation studies using casein kinase 1 (CK-1) and casein kinase 2 (CK-2) revealed that EBNA-2 is a substrate for CK-2, but not for CK-1. The CK-2 specific phosphorylation site was localized in the 140 C-terminal amino acids using a recombinant trpE-C-terminal fusion protein. In a similar experiment, the 58 N-terminal amino acids expressed as a recombinant trpE-fusion protein were not phosphorylated. Phosphorylation of a synthetic peptide corresponding to amino acids 464-476 of EBNA-2 as a substrate led to the incorporation of 0.69 mol phosphate/mol peptide indicating that only one of three potential phosphorylation sites within the peptide was modified. The most likely amino acid residues for phosphorylation by CK-2 are Ser469 and Ser470.
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PMID:Phosphorylation of the Epstein-Barr virus nuclear antigen 2. 132 72

The subcellular distribution of the small Epstein-Barr virus-encoded RNAs EBER-1 and EBER-2 has been investigated by using a high-resolution in situ hybridization technique. The distribution patterns in Raji cells of fluorescent oligodeoxynucleotides complementary to each RNA were detected by confocal laser scanning microscopy. Both RNAs were found in the cytoplasm as well as in the nuclei of interphase cells. In contrast, use of the same technique indicated an exclusively nuclear location for cellular U2 RNA. In the cytoplasm distribution of the EBERs was similar to that of the double-stranded RNA-dependent protein kinase, to which these RNAs can bind, and was coincident with the rough endoplasmic reticulum. In cells undergoing mitosis the EBERs became localized around the chromosomes, whereas the protein kinase remained uniformly distributed in the cytoplasm. A cytoplasmic location for EBER-1 and EBER-2 in interphase cells is consistent with the evidence for a role for these small RNAs in translational control.
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PMID:Localization of Epstein-Barr virus-encoded RNAs EBER-1 and EBER-2 in interphase and mitotic Burkitt lymphoma cells. 133 43

Epstein-Barr virus encodes two small RNAs, EBER-1 and -2, that are abundantly expressed in latently infected cells. Recent evidence suggests a role for EBER-1 in regulation of translation since this RNA is able to prevent the inhibition of protein synthesis by double-stranded RNA in rabbit reticulocyte lysates. We show here that EBER-1 that has been synthesized in vitro forms a complex with the dsRNA-activated inhibitor of protein synthesis DAI, a protein kinase that specifically phosphorylates polypeptide chain initiation factor eIF-2. Gel retardation assays and UV crosslinking experiments indicate that complex formation is specific for EBER-1 and requires the presence of some secondary structure in the molecule. RNA competition studies show that EBER-1-DAI complex formation is not inhibited in the presence of other small RNA species, heparin or the synthetic double-stranded RNA, poly(I).poly(C). SDS gel analysis reveals the existence of two forms of the crosslinked complex, of 64-68kDa and 46-53kDa, both of which are recognized by anti-DAI antibodies in immunoprecipitation experiments. These data suggest that EBER-1 regulates protein synthesis through its ability to interact with DAI.
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PMID:Binding of Epstein-Barr virus small RNA EBER-1 to the double-stranded RNA-activated protein kinase DAI. 167 26

An Epstein-Barr virus protein associated with the restricted component of the early antigen complex was characterized in this study. This protein was of particular interest because of its homology to polyoma middle T antigen and to the product of the bcl-2 oncogene. The results from this study reveal that this protein had a number of unusual properties in comparison with other polypeptides associated with the early antigen complex. For example, the synthesis of this membrane-associated antigen was regulated by the cell cycle, and its expression was compatible with cell survival. Functional studies reveal that immunoprecipitates containing this protein exhibited a threonine-serine-specific protein kinase activity. The results suggest that this protein might function in both the immortalization and replication cycles of this virus.
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PMID:Protein kinase activity associated with a cell cycle regulated, membrane-bound Epstein-Barr virus induced early antigen. 215 54

This paper presents data on the effects of interferon treatment on Epstein-Barr virus (EBV) gene expression in latently infected Daudi Burkitt's lymphoma cells, and reviews the possible role of viral gene products in the regulation of translation. In Daudi cells the main virally coded RNAs are the small untranslated RNAs EBER-1 and EBER-2, two mRNAs for the DNA binding protein EBNA-1, and a number of small RNAs containing sequences from the BamHI W repeat region of the viral genome. Interferon treatment does not change the qualitative pattern of EBV gene expression but decreases the levels of the EBNA-1 mRNAs. The chromatographic behaviour of EBV-encoded RNAs on CF11-cellulose indicates that many contain double-stranded regions; these RNAs co-purify with RNA that activates the interferon-induced, dsRNA-sensitive protein kinase DAI. Computer analysis indicates that the exons transcribed from the BamHI W repeats have the potential for formation of very stable secondary structures. Many viruses can counteract the inhibition of protein synthesis mediated by the DAI-catalysed phosphorylation of initiation factor eIF-2 and our data suggest that the small RNA EBER-1 may fulfil this function in the EBV system. During the infection and immortalization of B lymphocytes by EBV the synthesis of large amounts of EBER-1 RNA might thus allow the virus to circumvent one of the interferon-mediated mechanisms of host cell defence.
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PMID:Epstein-Barr virus gene expression in interferon-treated cells. Implications for the regulation of protein synthesis and the antiviral state. 216 91

A role for the Epstein-Barr virus small RNA species EBER-1 in the regulation of protein synthesis has been investigated in the reticulocyte-lysate cell-free translation system. Recombinant EBER-1 was synthesized by in vitro transcription of a plasmid containing the viral gene and purified by CF11-cellulose chromatography and ribonuclease III treatment. When added to the reticulocyte lysate at 10-20 micrograms/ml or more, EBER-1 prevents the inhibition of protein synthesis caused by low concentrations of synthetic double-stranded RNA, poly(I).poly(C). This effect is eliminated by treatment of the recombinant EBER-1 with ribonuclease T1. Disruption of the secondary structure of EBER-1 by substitution of inosine for guanosine in the in-vitro-synthesized RNA impairs the ability of EBER-1 to prevent the poly(I).poly(C)-mediated inhibition of protein synthesis. These results suggest that high concentrations of EBER-1 regulate protein synthesis by blocking the activation of the double-stranded RNA-dependent eukaryotic initiation factor 2 alpha (eIF-2 alpha) protein kinase DAI (p68), and that this property is dependent on the secondary structure of the small RNA molecule.
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PMID:Translational control by the Epstein-Barr virus small RNA EBER-1. Reversal of the double-stranded RNA-induced inhibition of protein synthesis in reticulocyte lysates. 217 60

The expression of interferon-gamma (IFN-gamma) receptors on normal human B cells and four B cell lines was studied. Recombinant human IFN-gamma was labeled with [gamma-32P]ATP using the catalytic subunit of a cAMP-dependent protein kinase. All four B cell lines, although differing in their responsiveness to IFN-gamma, were found to express high-affinity receptors (1,000-11,000 receptors/cell). Normal unactivated B lymphocytes were also found to express constitutively high-affinity receptors, approximately 1,400 receptors per cell with an estimated affinity of 295 pM. Activation of the normal B cells in vitro with the polyclonal B cell activator, Staphylococcus aureus Cowan strain I (SAC), resulted in a slight decline in receptor number and a more pronounced fall in receptor density. One of the B cell lines and unactivated normal B cells were shown to internalize labeled IFN-gamma rapidly. Chemical cross-linking of 32P-IFN-gamma to the CB B cell line and to freshly isolated B lymphocytes revealed one major cross-linked receptor-ligand complex which had an estimated molecular weight of approximately 110 kilodaltons. This complex corresponded to a 93 kD receptor cross-linked to recombinant IFN-gamma. Our data indicate that normal B lymphocytes constitutively express an approximately 93 kD IFN-gamma receptor which is similar to the receptor present on Epstein-Barr virus-transformed B cell lines.
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PMID:Demonstration and partial characterization of the interferon-gamma receptor on human B lymphocytes. 252 54


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