Nur77 forms novel nuclear structures upon DNA damage that cause transcriptional arrest

Area of Science:

• Cell Biology
• Molecular Biology
• Genetics

Background:

• The orphan nuclear receptor Nur77 plays a role in cell growth and apoptosis.
• Nur77 activity is regulated by its intracellular distribution.
• Genotoxic stress can induce cellular responses impacting cell fate.

Purpose of the Study:

• To investigate the role of Nur77 intracellular redistribution in response to genotoxic stress.
• To characterize the formation and properties of Nur77-containing nuclear structures under DNA damage.
• To understand the functional implications of Nur77 redistribution on its transcriptional activity and role in cell death.

Main Methods:

• Utilized green fluorescent protein (GFP)-tagged Nur77 to visualize its subcellular localization.
• Applied selected DNA damaging agents and transcription inhibitors to induce genotoxic stress.
• Analyzed the formation of transient nuclear structures and their association with the nuclear matrix.
• Assessed the correlation between Nur77 nuclear body formation and Nur77 transcriptional activity.

Main Results:

• Genotoxic stress and transcription inhibition induced rapid redistribution of Nur77.
• Nur77 formed distinct, transient nuclear structures not resembling conventional nuclear bodies.
• These novel nuclear structures were tightly bound to the nuclear matrix.
• Nur77 redistribution into these structures correlated with inhibition of Nur77 transcriptional activity.

Conclusions:

• Nur77 undergoes significant intracellular redistribution upon genotoxic stress.
• The formation of Nur77-bound nuclear structures is a response to DNA damage and transcription inhibition.
• These structures may sequester Nur77, inhibiting its transcriptional function.
• Nur77 nuclear body formation could be a mechanism in programmed cell death modulation by sequestering this proapoptotic factor.