There is provided a novel promoter useful for altering flow color of plants. The present invention relates to a nucleic acid selected from the group consisting of: (1) a nucleic acid containing the nucleotide sequence indicated in SEQ ID NO. 1; (2) a nucleic acid able to function as a transcriptional regulatory region of perilla anthocyanin 3-acyltransferase, and containing a nucleotide sequence in which the nucleotide sequence indicated in SEQ ID NO. 1 has been modified by addition, deletion and/or substitution of one or several nucleotides; (3) a nucleic acid able to function as a transcriptional regulatory region of perilla anthocyanin 3-acyltransferase, and able to hybridize under high stringent conditions with a nucleic acid consisting of a nucleotide sequence complementary to the nucleotide sequence indicated in SEQ ID NO. 1; and, (4) a nucleic acid able to function as a transcriptional regulatory region of perilla anthocyanin 3-acyltransferase, and having sequence identity of at least 90% with the nucleotide sequence indicated in SEQ ID NO. 1.