# The role of DNA methylation dynamics and patterning in postmitotic neuronal-maturation

> **NIH NIH R01** · SALK INSTITUTE FOR BIOLOGICAL STUDIES · 2020 · $665,983

## Abstract

Abstract
Cytosine methylation and histone modification are epigenomic marks with effects on transposable elements
(TE), transcription of genes and heterochromatin formation. While occurring mainly in a CG-dinucleotide
context, DNA methylation in brain cells contains nearly an equal amount of non-CG methylation (mCH). mCH
accumulates in neurons and correlates with transcriptional repression at a period coinciding with
synaptogenesis and neuronal maturation. Embryonic CG-methylation patterns also change dramatically during
the period between birth and the second postnatal week. The DNA methyltransferase Dnmt3a is highly
expressed in brain during this period. Preliminary data in this application suggests that this enzyme is
responsible for the accumulation of mC in neurons during the perinatal period. A conditional knockout mouse
was created, in which deletion of Dnmt3a in pyramidal neurons occurs during the late embryonic period (~E15,
driven by Neurod6-Cre). Contrary to results showing a shortened lifespan in animals with earlier embryonic
deletion (driven by Nestin-Cre), or lack of phenotype when the deletion occurs past the second postnatal week
(driven by CamK2a-Cre), NeuroD6-driven Dnmt3a-KO (pyrDnmt3a-KO) animals show no postnatal mC
accumulation, have significantly altered gene expression, and develop pronounced changes in behavior
without changes in lifespan. These results support the hypothesis that mC accumulation and patterning in
neurons requires precise regulation of Dnmt3a activity during neuronal development. Based on these findings,
it is proposed that mC accumulation during the perinatal period may be essential for the spatial and temporal
gene regulation required for proper synapse development and circuit formation. This hypothesis will be tested
by delineating the dynamics of Dnmt3a-dependent mC accumulation during brain development, by
characterizing the disruptions in methylation patterns, transcriptional dysregulation and histone modifications in
animals carrying a deletion of Dnmt3a in pyramidal and inhibitory neurons from cortex and hippocampus (Aim
1). To understand the mechanisms of activation of Dnmt3a during postnatal cortical development, this proposal
will identify its binding-partners during the developmental transition between the first and second postnatal
week in neurons using mass spectrometry of Dnmt3a immunocomplexes. It will also assess the requirement of
these binding partners for Dnmt3a function by transcriptional knockdown experiments in cultured cells and
animals using a viral deliver system (Aim2). Finally, this proposal will characterize the effects of Dnmt3a
deletion on neuron development and synaptogenesis (Aim3).

## Key facts

- **NIH application ID:** 9851963
- **Project number:** 5R01MH112763-04
- **Recipient organization:** SALK INSTITUTE FOR BIOLOGICAL STUDIES
- **Principal Investigator:** MARIA MARGARITA BEHRENS
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $665,983
- **Award type:** 5
- **Project period:** 2017-03-16 → 2022-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9851963

## Citation

> US National Institutes of Health, RePORTER application 9851963, The role of DNA methylation dynamics and patterning in postmitotic neuronal-maturation (5R01MH112763-04). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9851963. Licensed CC0.

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