ADA2 Forms Nuclear Condensates with GCN5 and ATP-Citrate Lyase (ACL) to Modulate H3K9 Acetylation at Genes...

Area of Science:

• Plant Biology
• Molecular Biology
• Biochemistry

Background:

• The Spt-Ada-Gcn5 acetyltransferase (SAGA) complex is vital for gene transcription.
• GCN5 is the catalytic subunit, and ADA2 is an adaptor enhancing HAT activity.

Purpose of the Study:

• To investigate the novel functions of ADA2 in rice.
• To elucidate the mechanism of histone acetylation in plant development.

Main Methods:

• Investigated intrinsically disordered regions (IDRs) and nuclear condensate formation.
• Analyzed interactions between SAGA complex and ATP-citrate lyase (ACL).
• Utilized genetic knock-out/suppression and assessed histone acetylation levels.

Main Results:

• Rice ADA2's intrinsically disordered region (IDR) drives nuclear condensate formation.
• A novel GCN5-ADA2-ACL (GAA) complex was identified, with ADA2 promoting condensation.
• ACL within condensates enriches acetyl-CoA, enhancing histone acetylation.
• Gene suppression/knock-out reduced meristem size, branch primordia, and H3K9 acetylation.

Conclusions:

• A new mechanism of histone acetylation involving phase separation and acetyl-CoA enrichment was discovered.
• This process is crucial for meristem development in rice.
• The GAA complex plays a key role in regulating essential genes for meristem function.