A region of the rat FAS (fatty acid synthase) promoter has been defined as being responsible for RA (retinoic acid) responsiveness. The defined promoter region is devoid of canonical RA-response elements but contains cis-elements binding generalized and specific transcription factors that mediate the dietary response of FAS. Our results are consistent with SREBP-1c (sterol-regulatory-element-binding protein 1c) binding in this region, thus bringing about the RA responsiveness of the rat FAS proximal promoter.