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Genome-wide Analysis using ChIP to Identify Isoform-specific Gene Targets
Published on: July 7, 2010
RCC1 isoforms differ in their affinity for chromatin, molecular interactions and regulation by phosphorylation
1Biomedical Research Centre, Level 5, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, UK.
Journal of Cell Science
|September 15, 2007
Summary
Human cells express at least three RCC1 (Regulator of Chromosome Condensation 1) isoforms with distinct functions. These isoforms, differing in their N-terminal regions, exhibit unique chromatin binding and phosphorylation patterns, impacting mitosis.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- RCC1 (Regulator of Chromosome Condensation 1) is a guanine nucleotide exchange factor for Ran GTPase, crucial for nucleocytoplasmic transport and mitotic events.
- Ran-GTP generation by RCC1 on chromatin acts as a spatial signal for essential cellular processes.
Purpose of the Study:
- To investigate the existence and functional differences of human RCC1 isoforms.
- To characterize the distinct properties of RCC1alpha, RCC1beta, and RCC1gamma isoforms, focusing on their N-terminal regions (NTRs).
Main Methods:
- Analysis of RCC1 isoform expression in human cells.
- Characterization of isoform-specific interactions with chromatin and importins (alpha3 and beta).
- Investigation of phosphorylation sites, particularly serine 11, and their impact on RCC1gamma function during mitosis.
Main Results:
- Human cells express at least three RCC1 isoforms: RCC1alpha, RCC1beta, and RCC1gamma, with varying tissue expression levels.
- RCC1beta and RCC1gamma possess unique N-terminal regions (NTRs) mediating chromatin interaction and importin binding.
- RCC1gamma exhibits stronger chromatin binding and reduced importin interaction compared to RCC1alpha, with significant phosphorylation at serine 11 during mitosis, impacting cell proliferation.
Conclusions:
- Human RCC1 isoforms possess distinct chromatin binding affinities and molecular interaction profiles.
- The N-terminal regions (NTRs) dictate isoform-specific properties and regulation by phosphorylation.
- Phosphorylation of RCC1gamma at serine 11 plays a critical role in regulating its function during mitosis.
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