Zajaczkowski, E. | bioRxiv Science

bioRxiv2023

DNA G-quadruplex is a transcriptional control device that regulates memory

The conformational state of DNA fine-tunes the transcriptional rate and abundance of RNA. Here we report that DNA G-quadruplex (G4-DNA) accumulates in neurons in an experience-dependent manner, and that this is required for the transient silencing and activation of genes that are critically involved in learning and memory. In addition, site-specific resolution of G4-DNA by dCas9-mediated deposition of the helicase DHX36 impairs fear extinction memory. Dynamic DNA structure states therefore represent a key molecular mechanism underlying memory consolidation. One-Sentence SummaryG4-DNA is a molecular switch that enables the temporal regulation of the gene expression underlying the formation of fear extinction memory.

neuroscience↗

bioRxiv2019

Dynamic DNA structure states interact with the RNA editing enzyme ADAR1 to modulate fear extinction memory

RNA modification has recently emerged as an important mechanism underlying gene diversity linked to behavioral regulation. The conversion of adenosine to inosine by the ADAR family of enzymes is a particularly important RNA modification as it impacts the physiological readout of protein-coding genes. However, not all variants of ADAR appear to act solely on RNA. ADAR1 binds directly to DNA when it is in a non-canonical, left handed, \"Z\" conformation, but little is known about the functional relevance of this interaction. Here we report that ADAR1 binds to Z-DNA in an activity-dependent manner and that fear extinction learning leads to increased ADAR1 occupancy at DNA repetitive elements, with targets adopting a Z-DNA structure at sites of ADAR1 recruitment. Knockdown of ADAR1 leads to an inability to modify a previously acquired memory trace and this is associated with a concomitant change in DNA structure and a decrease in RNA editing. These findings suggest a novel mechanism of learning-induced gene regulation whereby ADAR1 physically interacts with Z-DNA in order to mediate its effect on RNA, and both are required for memory flexibility following fear extinction learning.

neuroscience↗