Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.1.21 (thymidine kinase)
 7,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Apoptosis is the physiological process by which unwanted cells in an organism are killed. Bcl-2, a membrane-bound cytoplasmic protein, and its close relative Bcl-xL, are both effective inhibitors of apoptosis induced by a wide variety of stimuli in many different cell types. In a previous study, we reported that suppression of apoptosis by Bcl-2 or Bcl-xL, markedly elevates the levels of radiation-induced mutations at the specific locus thymidine kinase. We investigated the effect of the Bcl-2 or Bcl-xL overproduction on hydrogen peroxide-induced mutagenesis. Oxidative DNA damage has been implicated in biological processes such as mutagenesis, carcinogenesis and aging. Overexpression of either Bcl-2 or Bcl-xL enhances oxidative stress mutagenesis in cells with wild type p53 as well as with mutated p53 protein. These results support the hypothesis that apoptosis plays a crucial role in maintaining genomic integrity by selectively eliminating highly mutated cells from the population.
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PMID:Suppression of apoptosis by overexpression of Bcl-2 or Bcl-xL promotes survival and mutagenesis after oxidative damage. 946

Episomal vectors, described for efficient and regulated expression of heterologous proteins in mammalian cells, have the advantage that they persist in multiple copies in the cell without integrating into the chromosome. To efficiently express heterologous proteins we used such a vector based on elements of the Epstein-Barr virus (EBV), namely the sequences coding for Epstein-Barr nuclear antigen 1 and the viral origin of replication. Because constitutive expression is often deleterious to the cell, we combined the interferon-inducible Mx promoter with this EBV-derived vector. This resulted in an efficient and strictly regulated expression of the reporter gene chloramphenicol acetyltransferase (CAT) and of the neurotransmitter receptor h5-HT(1B), reaching levels of 16 ng CAT/mg cytoplasmic protein and 1300 fmol receptor/mg membrane protein, respectively. For both proteins, the expression levels were influenced by the orientation of the expression cassette. The higher expression in the favored orientation did not result from a higher copy number of these episomes. Northern analysis revealed a transcriptional read-through from the thymidine kinase promoter on the episomal vector, which interfered with the transcription of the heterologous gene in the less favored orientation.
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PMID:Orientation-dependent gene expression with Epstein-Barr virus-derived vectors. 1467 61

The presence of thymidine kinase (TK) is a feature of many large DNA viruses. Here, a TK gene homologue was cloned and characterized from Rana grylio virus (RGV), a member of family Iridoviridae. RGV TK encodes a protein of 195 aa with a predicted molecular mass of 22.1 kDa. Homologues of the protein were present in all the currently sequenced iridoviruses, and phylogenetic analysis showed that it was much close to cellular TK type 2 (TK2), deoxycytidine kinase (dCK) and deoxyguanosine kinase (dGK). Subsequently, Western blotting revealed TK expression increased with time from 6 h post-infection in RGV-infected cells. Using drug inhibition analysis by protein synthesis inhibitor (cycloheximide) and DNA replication inhibitor (cytosine arabinofuranoside), RGV TK was classified as the early expression gene during in vitro infection. Subcellular localization by TK-GFP fusion protein expression and immunofluorescence staining showed RGV TK was an exclusively cytoplasmic protein in fish cells. Collectively, current data indicate that RGV TK was an early gene of iridovirus which encoded a cytoplasmic protein in fish cells.
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PMID:Rana grylio virus thymidine kinase gene: an early gene of iridovirus encoding for a cytoplasmic protein. 1912 19