Page 20 - C. Biotechnology and molecular imaging

[C. Biotechnology and molecular imaging-12]

Dynamic Visualization of Osmotic Stress-Induced Redox

Reaction in Nucleus by FRET-based Redox Biosensor

Jung-Soo Suh¹, Heon-Su Kim¹, Tae-Jin Kim¹˙²˙*

¹Integrated Biological Science, Pusan National University, Busan 46241, Republic of Korea, ²Biological Sciences,

Pusan National University, Busan 46241, Republic of Korea

Redox reactions are critical for numerous cellular processes, including energy metabolism, cell cycle, gene expression
and regulation. However, it remains unclear how redox activity is regulated in the subcellular organelle. In this study,

we have developed a nucleus-targeted redox biosensor based on fluorescence resonance energy transfer to visualize

the spatiotemporal dynamics of redox reactions in the nucleus. Our results reveal that salt-induced osmotic stress
stimulates nuclear redox reactions, but a similar event is rarely detected in the nucleus of H2O2-treated cells. We
further demonstrate that redox stress tolerance occurs only in the nucleolus, known as the main site of ribosome

biogenesis, as compared to the nucleoplasm region, which could be due to aggregation of peroxiredoxin-I. Thus,
our data suggest that salt-induced redox stress acts to the minimum in the nucleolus, membrane-less organelles

where antioxidants can serve as alternative protection against osmotic/redox stress.