Molecular cloning and characterization of a cDNA encoding nitrate reductase from Chlorella ellipsoidea (Chlorophyta)

Nitrate reductase (NR) genes have been cloned from higher plants, fungi and algae. Based on seven of the amino acid residues most strongly conserved between Chlorella vulgaries and Chlamydomonas reinhardtii NR gene, a degenerate primer was designed. This degenerate primer was used to amplify the corresponding homology in Chlorella ellipsoidea. A 3304 bp full-length cDNA was cloned by rapid amplification of cDNA ends (RACE). The deduced amino acid sequence of this cDNA has a high degree of similarity with previously identified members of the NR gene. This suggests that the amplified cDNA encodes a functional NR. Northern blot expression analysis suggests that this gene is strongly induced by nitrate, but is repressed by ammonium. The nucleotide sequence data reported in this paper will appear in the DDBJ/EMBL/GeneBank databases under accession number AY275834.