Curation was carried out for transcriptional regulation information on promoters. Exhaustive literature search for target genes of individual transcription factors was carried out, binding motifs and experimental evidence were recorded, and transcription factor binding motifs were mapped on promoters of the target genes. Binding quality levels were assigned based on definitiveness of the binding evidence, which was determined by the experimental approaches employed to demonstrate the binding and expert data interpretation. A standardized curation format has been developed for easy data entry and automated data loading into the database. To best preserve the curated association between motifs and promoters through changes such as genome assembly releases and genome annotations, we also record motif flanking sequences.