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Updated: Aug 10, 2026

Genome-wide Analysis using ChIP to Identify Isoform-specific Gene Targets
Published on: July 7, 2010
Spatial and topological distribution of progesterone receptor A and B isoforms during human development
T Inoue1, J I Akahira, J Takeyama
1Department of Pathology, Tohoku University School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980 8575, Japan. tsukasai@gonryo.med.tohoku.ac.jp
Abstract:
Progesterone receptor (PR) is a member of the nuclear receptor superfamily. To date, two isoforms of PR have been identified, PR-A and PR-B. In progesterone responsive tissues, the relative ratio of PR-A and PR-B is considered to contribute to the tissue-specific actions of progesterone. In this study, we examined the distribution of PR-A and PR-B in human fetal tissues ranging from 11 to 40 gestational weeks using immunohistochemistry and RT-PCR analysis. PR immunoreactivity was detected in a wide range of fetal tissues until 20 weeks of gestation, but gradually decreased towards the late gestational period. However, PR continued to remain positive throughout the gestational period in the interstitial cells of Cajal and endocrine tissues. PR-B was demonstrated as the predominant isoform in comparison to PR-A in all fetal tissues examined. These findings suggest that progesterone may be involved in the development of fetal organs throughout the gestational period.
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