Visualization by BiFC of different C/EBP{beta} dimers and their interaction with HP1{alpha} reveals a differential subnuclear distribution of complexes in living cells

Journal Article · Fri Apr 01 04:00:00 EDT 2011 · Experimental Cell Research

DOI:https://doi.org/10.1016/J.YEXCR.2010.11.008· OSTI ID:22212103

Susperreguy, Sebastian; Prendes, Luciana P.; Desbats, Maria A.; Charo, Nancy L. ^[1]; Brown, Karen ^[2]; MacDougald, Ormond A. ^[3]; Kerppola, Tom ^[4]; Schwartz, Jessica ^[3]; Piwien-Pilipuk, Graciela ^[1]

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1. Instituto de Biologia y Medicina Experimental, CONICET, Buenos Aires (Argentina)
2. Chromosome Biology Group, Imperial College of London, London (United Kingdom)
3. Dept. of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI (United States)
4. Dept. of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI (United States)

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/EBP{beta} not only associates with pericentromeric heterochromatin but also interacts with the nucleoskeleton upon induction of adipocyte differentiation of 3T3-L1 cells. Different C/EBP{beta} 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 HP1{alpha}. HP1{alpha} inhibits LAP transcriptional capacity and occupies the promoter of the C/EBP{beta}-dependent gene c/ebp{alpha} in 3T3-L1 preadipocytes. When adipogenesis is induced, HP1{alpha} binding decreases from c/ebp{alpha} promoter, allowing transcription. Thus, the equilibrium among different pools of C/EBP{beta} associated with chromatin or nucleoskeleton, and dynamic changes in their interaction with HP1{alpha}, play key roles in the regulation of C/EBP target genes during adipogenesis.

• OSTI ID: 22212103
• Journal Information: Experimental Cell Research, Journal Name: Experimental Cell Research Journal Issue: 6 Vol. 317; ISSN 0014-4827; ISSN ECREAL
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
CELL NUCLEI
DIMERS
GENES
HETEROCHROMATIN
LIVER
PROMOTERS
TRANSCRIPTION FACTORS