Tobacco Nia2 cDNA functionally complements a Hansenula polymorpha yeast mutant lacking nitrate reductase. A new expression system for the study of plant proteins involved in nitrate assimilation.

摘要: An integrative expression vector based on promoter and terminator transcriptional sequences from the Hansenula polymorpha nitrate reductase gene (YNR1) has been developed to express assimilation plant genes in assimilatory yeast H. polymorpha. Using this a cDNA (tobacco Nia2) was expressed for first time yeast. The heterologous produced retained its biochemical physiological properties such as NADH-dependent activity, allowed growth containing media strain lacking endogenous activity. In transgenic strain, maximum tobacco activity about 70% of that presented wild-type. On other hand, disappearance correlated with enzyme protein response addition ammonium medium took place more rapidly than Nitrate recombinant assayed presence Mg2+ 30% observed when EDTA. This result, together decreased rate nitrate, suggests could be partially inactivated by phosphorylation binding 14-3-3-like proteins. These results show is useful system studying proteins involved assimilation.