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The PcG protein HPC2 inhibits RBP‐J‐mediated transcription by interacting with LIM protein KyoT2
Author(s) -
Qin Hongyan,
Du Dewei,
Zhu Yangting,
Li Junfeng,
Feng Lei,
Liang Yingmin,
Han Hua
Publication year - 2005
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2005.01.022
Subject(s) - transactivation , immunoprecipitation , transcription factor , dna binding protein , transcription (linguistics) , microbiology and biotechnology , suppressor , chemistry , promoter , histone , chromatin immunoprecipitation , nuclear protein , plasma protein binding , biology , dna , gene , gene expression , biochemistry , linguistics , philosophy
The DNA‐binding protein recombination signal‐binding protein‐Jk (RBP‐J) plays a key role in transcriptional regulation by targeting the intracellular domain of Notch (NIC) and the Epstein–Barr virus nuclear antigen 2 (EBNA2) to specific promoters. In the absence of the Notch signaling, RBP‐J acts as a transcriptional suppressor through recruiting co‐suppressors such as histone deacetylase (HDAC). KyoT2 is a LIM domain protein that suppresses the RBP‐J‐mediated transcriptional activation. In the current study, we show that the polycomb group (PcG) protein HPC2, which functions as a transcriptional suppressor, is a candidate of KyoT2‐binding proteins. To confirm the physical and functional interaction between KyoT2 and HPC2, we carried out yeast two‐hybrid, GST‐pull down, co‐immunoprecipitation, as well as mammalian two‐hybrid assays. Our results showed HPC2 and KyoT2 interacted both in vitro and in vivo, probably through the C‐terminal fragment of HPC2 and LIM domains of KyoT2. In addition, we also found that overexpression of HPC2, not only inhibited transactivation of a RBP‐J‐dependent promoter by NIC, but also transactivation by RBP‐J–VP16, a constitutively active form of RBP‐J. Taken together, our results suggested that KyoT2 might inhibit the RBP‐J‐mediated transactivation through NIC by recruiting co‐suppressors such as HPC2.