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Exploring Sequence Space to Identify Binding Sites for Regulatory RNA-Binding Proteins
Published on: August 9, 2019
Hu proteins regulate polyadenylation by blocking sites containing U-rich sequences.
Hui Zhu1, Hua-Lin Zhou, Robert A Hasman
1Department of Genetics, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106, USA.
The Journal of Biological Chemistry
|November 28, 2006
Summary
Hu proteins, crucial for regulating gene expression, were found to control alternative polyadenylation by blocking specific poly(A) sites. This discovery reveals a new nuclear function for these RNA-binding proteins.
Area of Science:
- Molecular Biology
- Gene Regulation
- RNA Processing
Background:
- Alternative polyadenylation (APA) affects 54% of human genes, impacting gene expression and biological outcomes.
- Mechanisms regulating APA are not fully understood.
- Hu proteins, known cytoplasmic regulators of mRNA stability and translation, are neuron-specific RNA-binding proteins.
Purpose of the Study:
- To investigate the role of Hu proteins in polyadenylation regulation.
- To identify the mechanisms by which Hu proteins influence polyadenylation.
- To explore the nuclear functions of Hu proteins.
Main Methods:
- In vitro polyadenylation assays using HeLa cell nuclear extract and recombinant Hu proteins.
- Analysis of poly(A) site usage with mutated U-rich sequences.
- Overexpression of HuR in HeLa cells.
- Investigation of protein-RNA interactions involving Hu proteins, CPSF64, and CPSF160.
Main Results:
- Hu proteins selectively inhibit cleavage and poly(A) addition at U-rich poly(A) sites.
- This inhibitory activity requires all three RNA recognition motifs of Hu proteins.
- Hu protein overexpression blocks polyadenylation at U-rich poly(A) signals.
- Hu proteins interfere with the interaction between CPSF64 and RNA, likely via direct interaction with CPSF64 and CPSF160.
Conclusions:
- Hu proteins function as novel regulators of mammalian polyadenylation.
- Hu proteins possess a previously unrecognized nuclear role in controlling poly(A) site selection.
- These findings contribute to understanding the complex mechanisms of gene expression regulation.
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