An expression control sequence which controls expression of a target gene linked downstream of the expression control sequence depending on an intracellular concentration of an amino acid, wherein in a bacterial cell which harbors a DNA construct comprising the expression control sequence, a promoter linked upstream of the expression control sequence and the target gene linked downstream of the expression control sequence, frequency of termination in the expression control sequence, of transcription starting from the promoter is lowered by increase of an intracellular concentration of an amino acid, whereby expression of the target gene increases.