Improved Determination of Subnuclear Position Enabled by Three-Dimensional Membrane Reconstruction

Area of Science:

• Cell Biology
• Genetics
• Biophysics

Background:

• Chromatin biology, including transcriptional regulation and DNA repair, is influenced by nuclear compartment positioning.
• Dynamic and variable locus localization necessitates analysis across large cell populations over time.
• Robust, automatable methods are crucial for quantifying individual loci positions within the nuclear volume.

Purpose of the Study:

• To describe a novel 3D membrane reconstruction approach for precise nuclear volume mapping.
• To enable quantitative analysis of chromatin loci positions relative to the nuclear periphery.
• To provide a versatile image analysis pipeline for chromatin biology research.

Main Methods:

• Utilized fluorescently tagged nuclear envelope or endoplasmic reticulum membrane markers.
• Developed a 3D membrane reconstruction approach robust to various nuclear shapes.
• Combined with established methods to reconstruct diffraction-limited chromatin marker positions (e.g., lac Operator arrays bound by lacI-GFP).

Main Results:

• Precisely mapped nuclear volume in three dimensions, accommodating diverse nuclear shapes.
• Quantitatively determined the distribution of loci positions within the nuclear volume relative to the nuclear periphery.
• Demonstrated the utility of the image analysis pipeline for chromatin position studies.

Conclusions:

• The described 3D membrane reconstruction method offers accurate and robust nuclear volume mapping.
• This approach facilitates quantitative analysis of chromatin locus positioning within the nucleus.
• The stand-alone image analysis pipeline has broad utility for chromatin biology and organelle shape studies.