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Updated: Aug 30, 2026

In Vitro Selection of Engineered Transcriptional Repressors for Targeted Epigenetic Silencing
Published on: May 5, 2023
Corepressor SMRT specifically represses the transcriptional activity of orphan nuclear receptor hB1F/hLRH-1
Ping-Long Xu1, Yu-Ying Kong, You-Hua Xie
1State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, the Chinese Academy of Sciences, Shanghai 200031, China.
Abstract:
The orphan nuclear receptor hB1F (also known as NR5A2, LRH-1, FTF or CPF) plays important roles in regulating the expression of several cellular and viral genes actively involved in a wide range of biological processes such as the bile acid biosynthesis, liver specific gene regulatory network and hepatitis B virus replication. The activity of nuclear receptors is regulated by multiple mechanisms, including coactivation and corepression. In this study, it was found that the silencing mediator for retinoic acid receptor and thyroid hormone receptor (SMRT) specifically represses the transcriptional activity of hB1F, on either GAL4 dependent reporter system or the hB1F-responsive HBV enhancer II/core promoter. The repression imposed by SMRT is observed in different cell lines. Interestingly, hB1F couldn t interact with SMRT directly, as demonstrated by mammalian two-hybrid analysis or GST pull-down assay. Taken together, it can be concluded for the first time that the transcriptional activity of hB1F is regulated specifically by the corepressor SMRT via an indirect mechanism.
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