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CCAAT/enhancer binding protein alpha assembles essential cooperating factors in common subnuclear domains
F Schaufele1, J F Enwright, X Wang
1Metabolic Research Unit and Department of Medicine, University of California, San Francisco, California 94143-0540, USA. freds@metabolic.ucsf.edu
Molecular Endocrinology (Baltimore, Md.)
|October 2, 2001
Summary
CCAAT/enhancer binding protein alpha (C/EBP alpha) concentrates at pericentromeric chromatin, recruiting cofactors like CBP and TBP. This "intranuclear marshalling" influences gene regulation by organizing protein interactions at specific nuclear sites.
Area of Science:
- Molecular Biology
- Cell Biology
- Genetics
Background:
- CCAAT/enhancer binding protein alpha (C/EBP alpha) regulates the pituitary GH promoter.
- C/EBP alpha is crucial for activating dormant promoters in progenitor cell lines.
Purpose of the Study:
- To investigate the intranuclear localization and complex formation of C/EBP alpha.
- To understand how C/EBP alpha influences the distribution of transcriptional cofactors.
Main Methods:
- Utilized green fluorescent protein (GFP) fusion proteins to track C/EBP alpha, CREB-binding protein (CBP), and TATA binding protein (TBP) localization.
- Employed microscopy to observe protein distribution within GHFT1-5 pituitary progenitor cells.
Main Results:
- C/EBP alpha localized to pericentromeric chromosomal domains.
- C/EBP alpha expression induced the translocation of CBP and TBP to pericentromeric regions.
- Recruitment of CBP required C/EBP alpha's transcriptional activation domains.
Conclusions:
- C/EBP alpha actively organizes transcriptional complexes through "intranuclear marshalling."
- This organizational activity at specific nuclear sites may control gene expression by modulating cofactor interactions.