The assessment of NDRG1 expression offers valuable prognostic information for patients with colorectal cancer, especially for those with stage II disease. We propose that NDRG1 expression level could be used to select patients with stage II disease who are at increased risk of unfavorable outcome, and who may benefit from adjuvant therapy.

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A role for the Escherichia coli RNA polymerase alpha subunit in transcription antitermination dependent on bacteriophage lambda N protein has been previously inferred from the isolation of rpoA mutants that alter the efficiency of this process. This report describes studies on the efficiency of N-dependent transcription antitermination in a strain containing the rpoA341 mutation, which interferes with this process. The effect of mutations in genes coding for different Nus factors and/or plasmids overexpressing nus genes on bacteriophage lambda development in an E. coli rpoA341 host was examined. In addition, the effect of overproduction of the N protein in these genetic backgrounds was assessed. Analogous bacterial strains were employed to measure the efficiency of the antitermination process using the lacZ reporter gene under control of the lambda p(R) promoter, and containing the phage nutR region and the t( R1) terminator between the promoter and lacZ. The experimental results suggest interactions between components of the N-antitermination complex, which have been established biochemically, as well as additional functional relationships within the complex. Furthermore, the results indicate that amino acid substitution in the alpha subunit C-terminal domain encoded by the rpoA341 mutation may specifically disrupt the function of the NusA and NusE proteins. During this analysis, it was also found that the E. coli nusA1 mutant exhibits a conditional lethal phenotype.

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The cellular localization of the 35 kDa, low molecular mass acid metallophosphatase (LMW AcPase) from the frog (Rana esculenta) liver and its activity towards P-Ser and P-Tyr phosphorylated peptides were studied. This enzyme was localized to the cytoplasm of hepatocytes but did not appear in other cells of liver tissue (endothelium, macrophages, blood cells). This LMW AcPase does not display activity towards (32)P-phosphorylase a under conditions standard for the enzymes of PPP family. Proteins containing P-Ser: rabbit (32)P-phosphorylasea and phosvitin are hydrolysed only at acidic pH and are poor substrates for this enzyme. The frog AcPase is not inhibited by okadaic acid and F(-) ions, the Ser/Thr protein phosphatase inhibitors. Moreover, the frog enzyme does not cross-react with specific antisera directed against N-terminal fragment of human PP2A and C-terminal conserved fragment of the eukaryotic PP2A catalytic subunits. These results exclude LMW AcPase from belonging to Ser/Thr protein phosphatases: PP1c or PP2Ac. In addition to P-Tyr, this enzyme hydrolyses efficiently at acidic pH P-Tyr phosphorylated peptides (hirudin and gastrin fragments). K(m) value for the hirudin fragment (7.55 +/- 1.59 x 10(-6) M) is 2-3 orders of magnitude lower in comparison with other substrates tested. The enzyme is inhibited competitively by typical inhibitors of protein tyrosine phosphatases (PTPases): sodium orthovanadate, molybdate and tungstate. These results may suggest that the LMW AcPase of frog liver can act as PTPase in vivo. A different cellular localization and different response to inhibition by tetrahedral oxyanions (molybdate, vanadate and tungstate) provide further evidence that LMW AcPase of frog liver is distinct from the mammalian tartrate-resistant acid phosphatases.