Posttranscriptional control of nitrate reductase of cultured tobacco cells by amino acids.

Using the inhibitor of RNA synthesis, 4,5',8-trimethylpsoralen plus near ultraviolet light, the half-life of the rate-limiting RNA species required for the induction of nitrate reductase in XD cells of tobacco was estimated to be 4 hours. Amino acids, the end product of nitrate assimilation, reduced the half-life to 1 hour. It is suggested that amino acids exert a posttranscriptional control on the enzyme level.