Changes in gravitational force affect gene expression in developing organ systems at different developmental times

Area of Science:

• Developmental Biology
• Space Biology
• Genetics

Background:

• Limited understanding of microgravity's impact on in vivo embryonic gene expression.
• Transgenic zebrafish (beta-actin promoter driving GFP) used to study gene expression.
• Focus on effects of simulated microgravity on developing organ systems.

Purpose of the Study:

• Investigate the impact of simulated microgravity on gene expression in developing zebrafish organs.
• Identify specific developmental time windows of susceptibility to microgravity.
• Determine if developing organs recover from microgravity-induced gene expression changes.

Main Methods:

• Exposure of transgenic zebrafish to simulated microgravity at various developmental stages.
• Monitoring GFP expression in the heart, notochord, eye, somites, and Rohon-beard neurons.
• Quantifying changes in gene expression over different exposure durations.

Main Results:

• The developing heart showed a ~30% increase in gene expression between 32-56 hours post-fertilization.
• Notochord, eye, somites, and Rohon-beard neurons exhibited susceptibility between 24-72 hours post-fertilization.
• The notochord displayed a secondary susceptibility period from 8-32 hours post-fertilization; organs showed recovery by 80 hours.

Conclusions:

• Simulated microgravity exposure alters gene expression in multiple developing organ systems of live zebrafish embryos.
• Specific periods of maximum susceptibility to microgravity effects exist during embryonic development.
• Developing organs demonstrate a capacity for recovery despite ongoing simulated microgravity exposure.