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CRISPR-Mediated Reorganization of Chromatin Loop Structure
Published on: September 14, 2018
A positive role for NLI/Ldb1 in long-range beta-globin locus control region function.
Sang-Hyun Song1, Chunhui Hou, Ann Dean
1Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
Molecular Cell
|December 18, 2007
Summary
Nuclear factor NLI/Ldb1 mediates long-range gene activation by binding to the beta-globin locus control region. Its LIM domain is crucial for forming complexes that drive globin gene expression during development.
Area of Science:
- Molecular Biology
- Gene Regulation
- Developmental Biology
Background:
- Long-range interactions between regulatory elements and genes control gene expression specificity.
- Nuclear factor NLI/Ldb1 is a potential mediator of these interactions.
Purpose of the Study:
- To investigate the role of NLI/Ldb1 in mediating long-range gene activation at the beta-globin locus.
- To determine the specific domains of NLI/Ldb1 required for this function.
Main Methods:
- In vivo binding studies of NLI/Ldb1 and associated factors to the beta-globin locus control region.
- Analysis of NLI/Ldb1 mutant proteins lacking the LIM interaction domain.
- RNA interference (shRNA) knockdown of NLI expression.
- Kinetic studies monitoring complex formation, RNA Polymerase II recruitment, and transcription during erythroid differentiation.
Main Results:
- NLI/Ldb1 and erythroid partners (GATA-1/SCL/LMO2) bind in vivo to the beta-globin locus control region.
- The C-terminal LIM interaction domain of NLI is essential for complex formation on chromatin.
- Loss of the LIM domain renders NLI a dominant-negative inhibitor of globin gene expression.
- NLI knockdown prevents beta-globin expression activation.
- The NLI/GATA-1/SCL/LMO2 complex forms at the beta-globin promoter during erythroid differentiation, coinciding with RNA Pol II recruitment and transcription.
Conclusions:
- NLI/Ldb1 plays a critical role in facilitating long-range gene activation at the beta-globin locus.
- The LIM domain of NLI is indispensable for its function in mediating chromatin interactions and gene expression.
- NLI acts as a key mediator in the complex regulatory network governing erythroid differentiation.
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