Gene repressive activity of RIP140 through direct interaction with CDK8 | JoVE Visualize

Gene repressive activity of RIP140 through direct interaction with CDK8

Shawna D Persaud¹, Wei-Hong Huang, Sung Wook Park

¹Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA.

Molecular Endocrinology (Baltimore, Md.)|August 27, 2011

View abstract on PubMed

Summary

Receptor interacting protein 140 (RIP140) replaces TRAP220(MED1) on the CrabpI promoter during adipocyte differentiation. Acetylated RIP140 directly interacts with CDK8, enhancing gene repression via recruitment of factors like G9a.

Area of Science:

Molecular Biology
Gene Regulation
Epigenetics

Background:

Receptor interacting protein 140 (RIP140) is a key gene repressor and its activity is modulated by posttranslational modifications.
During fibroblast-adipocyte differentiation, thyroid hormone (T3) biphasically regulates the Crabp1 gene, involving TRAP220(MED1) for activation and RIP140 for repression.

Purpose of the Study:

To investigate the mechanism of RIP140 replacing TRAP220(MED1) on the CrabpI promoter during adipocyte differentiation.
To elucidate the role of RIP140's posttranslational modifications, specifically lysine acetylation, in its interaction with CDK8 and gene repression.

Main Methods:

Chromatin immunoprecipitation assays to assess protein recruitment to the CrabpI promoter.
Co-immunoprecipitation to detect protein-protein interactions between RIP140 and CDK8.
Site-directed mutagenesis and acetylation-mimetic constructs to study RIP140 function.

Main Results:

RIP140 recruitment to the CrabpI promoter increases as TRAP220(MED1) recruitment decreases during the T3-repressive phase.
Lysine acetylation of RIP140 enhances its interaction with CDK8.
Acetylated RIP140 more effectively recruits CDK8, which in turn recruits repressive factors like G9a, leading to CrabpI gene repression.

Conclusions:

RIP140 replaces TRAP220(MED1) on the CrabpI promoter during T3-induced adipocyte differentiation.
A novel mechanism of gene repression involves RIP140 directly interacting with CDK8, facilitated by lysine acetylation, to modulate the transcription machinery.