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Engineering gene expression and protein synthesis by modulation of nuclear shape
Carson H Thomas1, Joel H Collier, Charles S Sfeir
1Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA.
Summary
Altering cell and nuclear shape influences gene expression and protein synthesis. Optimal nuclear distortion, measured by nuclear shape index (NSI), maximizes collagen I and osteocalcin production in osteogenic cells.
Area of Science:
- Cell biology
- Biophysics
- Molecular biology
Background:
- Understanding the interplay between cell/nuclear mechanics and gene expression is limited.
- Cell and nuclear shape are hypothesized to influence cellular functions.
- Investigating these relationships requires precise control over cellular morphology.
Purpose of the Study:
- To develop a method for studying gene-specific responses in cells with controlled nuclear shape and area.
- To investigate how nuclear shape affects gene expression and protein synthesis in primary osteogenic cells.
- To explore the relationship between nuclear shape index (NSI) and the synthesis of specific proteins and mRNA.
Main Methods:
- Utilized microfabricated substrates with controlled surface chemistry to confine cell attachment and spreading.
- Manipulated nuclear shape by controlling cell confinement on adhesive islands.
- Measured gene expression using reverse transcription in situ PCR and quantified protein synthesis.
- Calculated nuclear shape index (NSI) to quantify nuclear morphology.
Main Results:
- Altered nuclear shape directly impacted gene expression and protein synthesis.
- Collagen I synthesis showed a direct correlation with cell and nuclear shape, peaking at intermediate NSI values (6-8).
- Osteocalcin mRNA was detected in cells with constrained nuclear shapes but not in unconstrained cells with similar projected areas.
Conclusions:
- Cell and nuclear shape, particularly optimal nuclear distortion, are critical regulators of gene expression and protein synthesis.
- The findings suggest mechanisms involving transcription factor-DNA interactions, nuclear transport, or nuclear matrix organization.
- This integrated approach using microfabrication, in situ PCR, and NSI measurement provides a powerful system for studying cell mechanics and gene expression regulation.