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The promoter region and transcriptional regulation of the nuoA-N gene locus encoding the proton-translocating NADH:quinone oxidoreductase was analysed. A 560 bp intergenic region upstream of the nuo locus was followed by a gene (designated lrhA for LysR homologue A) coding for a gene regulator similar to those of the LysR family. Disruption of lrhA did not affect growth (respiratory or non-respiratory) or expression of nuo significantly. Transcriptional regulation of nuo by electron acceptors, electron donors and the transcriptional regulators ArcA, FNR, NarL and NarP, and by IHF (integration host factor) was studied with protein and operon fusions containing the promoter region up to base pair -277 ('nuo277') or up to base pair -89 ('nuo899'). The expression of the nuo277-lacZ fusions was subject to ArcA-mediated anaerobic repression and NarL(+ nitrate)-mediated anaerobic activation. FNR and IHF acted as weak repressors under anaerobic conditions. Expression of nuo899-lacZ was stimulated during anaerobic fumarate respiration and aerobically by C4 dicarboxylates. Therefore, expression of nuo is regulated by O2 and nitrate via ArcA, NarL, FNR and IHF at sites within the -277 region, and by other factors including C4 dicarboxylates at a site between -277 and -899. A physiological role for the transcriptional stimulation by O2 and nitrate is suggested.

Using the polymerase chain reaction (PCR), a human kidney glutathione S-transferase (GST) alpha cDNA clone (GST alpha 12 K) was synthesized; it is identical to a known liver GST alpha cDNA clone except for one base change (G----A), indicating that an alpha class gene expressed in human kidney is similar to one expressed in human liver. Comparisons were made in the expression of GST alpha and GST pi between renal cell carcinoma and adjacent non-neoplastic tissue. Messenger RNA expression in 30 cases was determined by Northern blotting, and GST protein from nine of these cases was analyzed by HPLC. The GST alpha gene products were expressed at near-zero levels. The GST pi gene product was the predominant GST in tumors, but was decreased in absolute amount compared with control tissue, the tumor/control ratios for the GST pi gene obtained by Northern blots and HPLC analysis being 0.50 +/- 0.07 and 0.36 +/- 0.07 respectively. The resulting pattern in renal cell carcinoma therefore shows a predominance of GST pi. Since it is assumed that renal cell carcinoma derives from the proximal tubular epithelial cells which are high in GST alpha, this implies a dedifferentation in the GST expression pattern.

The NADH:ubiquinone oxidoreductase (complex I) is made up of a peripheral part and a membrane part. The two parts are arranged perpendicular to each other and give the complex an unusual L-shaped structure. The peripheral part protrudes into the matrix space and constitutes the proximal segment of the electron pathway with the NADH-binding site, the FMN and at least three iron-sulfur clusters. The membrane part constitutes the distal segment of the electron pathway with at least one iron-sulfur cluster and the ubiquinone-binding site. Both parts are assembled separately and relationships of the major structural modules of the two parts with different bacterial enzymes suggest, that both parts also emerged independently in evolution. This assumption is further supported by the conserved order of bacterial complex I genes, which correlates with the topological arrangement of the corresponding subunits in the two parts of complex I.

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