Visualization by BiFC of Different C/EBPβ Dimers and Their Interaction with HP1α Reveals a Differential Subnuclear Distribution of Complexes in Living Cells
Overview
Authors
Affiliations
How the co-ordinated events of gene activation and silencing during cellular differentiation are influenced by spatial organization of the cell nucleus is still poorly understood. Little is known about the molecular mechanisms controlling subnuclear distribution of transcription factors, and their interplay with nuclear proteins that shape chromatin structure. Here we show that C/EBPβ not only associates with pericentromeric heterochromatin but also interacts with the nucleoskeleton upon induction of adipocyte differentiation of 3T3-L1 cells. Different C/EBPβ dimers localize in different nuclear domains. Using BiFC in living cells, we show that LAP (Liver Activating Protein) homodimers localize in euchromatin and heterochromatin. In contrast, LIP (Liver Inhibitory Protein) homodimers localize exclusively in heterochromatin. Importantly, their differential subnuclear distribution mirrors the site for interaction with HP1α. HP1α inhibits LAP transcriptional capacity and occupies the promoter of the C/EBPβ-dependent gene c/ebpα in 3T3-L1 preadipocytes. When adipogenesis is induced, HP1α binding decreases from c/ebpα promoter, allowing transcription. Thus, the equilibrium among different pools of C/EBPβ associated with chromatin or nucleoskeleton, and dynamic changes in their interaction with HP1α, play key roles in the regulation of C/EBP target genes during adipogenesis.
Dual-transgenic BiFC vector systems for protein-protein interaction analysis in plants.
Chen P, Ye M, Chen Y, Wang Q, Wang Q, Zhong M Front Genet. 2024; 15:1355568.
PMID: 38525241 PMC: 10957565. DOI: 10.3389/fgene.2024.1355568.
Organization of nuclear architecture during adipocyte differentiation.
Charo N, Rodriguez Ceschan M, Galigniana N, Toneatto J, Piwien-Pilipuk G Nucleus. 2016; 7(3):249-69.
PMID: 27416359 PMC: 5019015. DOI: 10.1080/19491034.2016.1197442.
Adipogenesis is under surveillance of Hsp90 and the high molecular weight Immunophilin FKBP51.
Toneatto J, Charo N, Galigniana N, Piwien-Pilipuk G Adipocyte. 2015; 4(4):239-47.
PMID: 26451279 PMC: 4573184. DOI: 10.1080/21623945.2015.1049401.
Structural Modeling of GR Interactions with the SWI/SNF Chromatin Remodeling Complex and C/EBP.
Muratcioglu S, Presman D, Pooley J, Grontved L, Hager G, Nussinov R Biophys J. 2015; 109(6):1227-39.
PMID: 26278180 PMC: 4576152. DOI: 10.1016/j.bpj.2015.06.044.
Golan Y, Berman B, Assaraf Y J Biol Chem. 2015; 290(14):9050-63.
PMID: 25657003 PMC: 4423692. DOI: 10.1074/jbc.M114.617332.