Symmetry analysis of cell nuclei

Area of Science:

• Cell Biology
• Biophysics
• Genomics

Background:

• Cell nucleus spatial symmetry is crucial for cellular function.
• Age-related changes can impact nuclear organization and chromatin distribution.
• Previous studies suggest alterations in chromatin density during aging.

Purpose of the Study:

• To develop and apply an algorithm for quantifying two-dimensional spatial symmetry in cell nuclei.
• To investigate age-related alterations in chromatin spatial symmetry within housefly Malpighian tubule nuclei.
• To characterize changes in low-, medium-, and high-density chromatin components (LDC, MDC, HDC) during aging.

Main Methods:

• Development of an algorithm to analyze cell nucleus spatial symmetry.
• Calculation of symmetry index (SI) for precise spatial symmetry.
• Calculation of quadrant symmetry index (QSI) for quadrant occupancy.
• Analysis of Malpighian tubule nuclei from adult houseflies of varying ages.

Main Results:

• A seven-fold increase in the spatial symmetry of high-density chromatin (HDC) was observed with age.
• A significant shift in symmetry profile occurred, changing from LDC-MDC-HDC to MDC-LDC-HDC.
• Increased HDC symmetry suggests localization at new nuclear sites, potentially involving ~60% of chromosomes.

Conclusions:

• The developed algorithm effectively quantifies nuclear spatial symmetry and its age-related changes.
• Aging in housefly Malpighian tubule nuclei is associated with significant alterations in chromatin spatial symmetry.
• The findings highlight dynamic changes in nuclear organization and chromatin distribution during the aging process.