Noncoding transcription by alternative RNA polymerases dynamically regulates an auxin-driven chromatin loop

Area of Science:

• Plant molecular biology
• Epigenetics
• Transcriptional regulation

Background:

• The eukaryotic epigenome is influenced by 3D genome topology.
• Epigenetic variations control transcriptional responses to developmental signals.

Purpose of the Study:

• To investigate the role of the Arabidopsis lincRNA APOLO in auxin response.
• To elucidate how APOLO affects chromatin topology and gene expression.

Main Methods:

• Analysis of APOLO transcription by RNA polymerases II and V.
• Investigating chromatin loop formation around the PID gene.
• Assessing the impact of APOLO expression on chromatin modifiers (DNA methylation, Polycomb complexes).

Main Results:

• APOLO is dually transcribed in response to auxin.
• APOLO regulates chromatin loop formation at the PID gene promoter.
• Changes in APOLO expression alter chromatin loop dynamics and PID expression.
• RNA-dependent DNA methylation, demethylation, and Polycomb complexes modulate loop dynamics.

Conclusions:

• Dual transcription of APOLO influences local chromatin topology.
• This mechanism directs auxin-controlled developmental outputs in neighboring genes.
• The findings suggest a widespread mechanism for plant adaptation and eukaryotic gene regulation.