Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Complementary DNA clones of mRNAs for sheep and goat NADPH-ferredoxin reductases (ferredoxin NADP+ oxidoreductase, EC 1.18.1.2) were isolated by the reverse transcriptase polymerase chain reaction method, and the complete nucleotide sequences of the coding and 3'-flanking regions of these cDNA clones were determined. Comparative analysis using the deduced amino acid sequences of NADPH-ferredoxin reductases clarified the interspecific conservation of the ferredoxin-binding and flavin adenine dinucleotide (FAD)-binding regions, confirming the results reported previously. During this study, we happened to identify an alternatively spliced mRNA that completely lacks exon 3, just adjacent to the FAD-binding region of the sheep NADPH-ferredoxin reductase cDNA clone. In the screening of other alternatively spliced mRNAs of NADPH-ferredoxin reductases derived from several steroidogenic organs, such as adrenocortices, testes, and ovaries of sheep and goats, only one kind of alternatively spliced mRNA as described above was detected in sheep adrenocortices. Then, we constructed Escherichia coli expression systems for these two forms of mRNA and analyzed their enzymatic properties. We found that the ability of the alternatively spliced NADPH-ferredoxin reductase protein to transfer electrons to ferredoxin is completely abolished because FAD binding is inhibited.
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PMID:Molecular cloning of sheep and goat ferredoxin reductase messenger ribonucleic acids, and identification of an alternatively spliced form of sheep ferredoxin reductase. 916 Jul 36

5-Fluorouracil (5-FU) is a frequently used antitumor drug. Recently, it has been shown that mRNA and protein levels of the ferredoxin reductase gene (gene, FDXR; protein, FR) increase drastically after 5-FU treatment in various cell lines including colorectal cancer. The induction is mediated by p53 and enhanced reactive oxygen species (ROS)-associated apoptosis. Thus, knowledge about FDXR expression in human tissue and expression of the known splice variants is critical for understanding this finding. A sensitive and specific reverse transcriptase polymerase chain reaction (RT-PCR) assay for quantification of FDXR mRNA levels including the splice variants, a biological active variant (-18 bp) and an inactive variant (+18 bp), was developed and used to measure mRNAs after 5-FU chemotherapy in colorectal tissues of 40 cancer patients prior to and after treatment with 5-FU for 14 days. Before treatment, the great majority of normal tissues expressed the splice variants in a 100:1 ratio in favor of the -18-variant similar to what has been reported for other tissues. In tumors, the mRNA levels of total FDXR and splice variants were approximately 2-fold higher compared to the normal tissue. After 5-FU treatment, levels of the +18-variant increased 17-fold in tumors and 31-fold in normal tissues, clearly shifting the ratio towards the +18-form. 5-FU-mediated -18-variant induction (>1) in normal (12/17) and tumor tissues (12/16) was apparently associated with response, while a balanced ratio (0.1-2) was associated with 5-FU resistance (n=5) based on the histological evaluation of the tissues.
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PMID:Influence of 5-fluorouracil on ferredoxin reductase mRNA splice variants in colorectal carcinomas. 2296 7