The localization of histone H3K27me3 demethylase Jmjd3 is dynamically regulated

Area of Science:

• Epigenetics and Gene Regulation
• Molecular Biology
• Cellular Biology

Background:

• Jmjd3 plays a key role in cellular differentiation and senescence.
• Jmjd3 demethylates histone 3 lysine 27 trimethylation (H3K27me3), impacting pluripotency.
• Control mechanisms for Jmjd3's demethylase activity remain largely unknown.

Purpose of the Study:

• To investigate the role of Jmjd3's subcellular localization in its H3K27me3 demethylase activity.
• To identify the regions and signals responsible for Jmjd3's nuclear import.
• To explore the dynamic regulation of Jmjd3's nucleocytoplasmic shuttling.

Main Methods:

• Subcellular localization analysis of Jmjd3 and its domains.
• Identification and functional testing of nuclear localization signals (NLSs).
• Fusion of Jmjd3's catalytic domain with a heterologous NLS.
• Analysis of Jmjd3 shuttling using leptomycin B and Exportin-1 inhibition in mouse embryonic fibroblasts.

Main Results:

• Nuclear localization of Jmjd3 is essential for H3K27me3 demethylation.
• The N-terminal region of Jmjd3 mediates its nuclear import via two classical NLSs.
• Forced nuclear localization of the catalytic domain enhances H3K27me3 demethylation.
• Endogenous Jmjd3 undergoes dynamic nucleocytoplasmic shuttling, regulated by Exportin-1.

Conclusions:

• Jmjd3's subcellular localization is dynamically regulated and crucial for controlling H3K27me3 levels.
• The N-terminal region and specific NLSs dictate Jmjd3's nuclear entry.
• Understanding Jmjd3's localization provides insights into epigenetic regulation of differentiation and pluripotency.