To allow study of the control of the promoter of the mouse progesterone receptor gene and its specific elements, we have isolated nine individual clones and selectively sequenced the 5' region, which includes 5' promoter sequence and the non-coding region. Sequence comparison was performed versus the progesterone receptor genes of other species. Moreover, potential estrogen response elements, progesterone response elements, and other transcription factor recognition sites were determined by sequence analysis. In addition, since it has been confirmed that chromatin structures are important for regulation of gene expression, we also examined them in different estrogen target organs using the DNase hypersensitivity assay. A different pattern of the DNase hypersensitivity sites was detected between uterus and mediobasal hypothalamus and these sites were close to specific recognition elements.