MeCP2 regulates Tet1-catalyzed demethylation, CTCF binding, and learning-dependent alternative splicing of the BDNF gene in Turtle

  1. Zhaoqing Zheng
  2. Ganesh Ambigapathy
  3. Joyce Keifer  Is a corresponding author
  1. University of South Dakota, United States

Abstract

MECP2 mutations underlying Rett syndrome cause widespread misregulation of gene expression. Functions for MeCP2 other than transcriptional are not well understood. In an ex vivo brain preparation from the pond turtle Trachemys scripta elegans, an intraexonic splicing event in the brain-derived neurotrophic factor (BDNF) gene generates a truncated mRNA transcript in naïve brain that is suppressed upon classical conditioning. MeCP2 and its partners, splicing factor Y-box binding protein 1 (YB-1) and methylcytosine dioxygenase 1 (Tet1), bind to BDNF chromatin in naïve but dissociate during conditioning; the dissociation correlating with decreased DNA methylation. Surprisingly, conditioning results in new occupancy of BDNF chromatin by DNA insulator protein CCCTC-binding factor (CTCF), which is associated with suppression of splicing in conditioning. Knockdown of MeCP2 shows it is instrumental for splicing and inhibits Tet1 and CTCF binding thereby negatively impacting DNA methylation and conditioning-dependent splicing regulation. Thus, mutations in MECP2 can have secondary effects on DNA methylation and alternative splicing.

Article and author information

Author details

  1. Zhaoqing Zheng

    Neuroscience Group, Basic Biomedical Sciences, University of South Dakota, Vermillion, United States
    Competing interests
    The authors declare that no competing interests exist.
  2. Ganesh Ambigapathy

    Neuroscience Group, Basic Biomedical Sciences, University of South Dakota, Vermillion, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-4491-8513
  3. Joyce Keifer

    Neuroscience Group, Basic Biomedical Sciences, University of South Dakota, Vermillion, United States
    For correspondence
    jkeifer@usd.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-5900-0414

Funding

National Institutes of Health (NS051187)

  • Joyce Keifer

Internal departmental grant funds

  • Joyce Keifer

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Ethics

Animal experimentation: All experiments involving the use of animals were performed in accordance with the guidelines of the National Institutes of Health and were approved by the USD Institutional Animal Care and Use Committee (protocol number, 08-06-14-17C).

Reviewing Editor

  1. Anne E West, Duke University School of Medicine, United States

Publication history

  1. Received: January 23, 2017
  2. Accepted: June 7, 2017
  3. Accepted Manuscript published: June 8, 2017 (version 1)
  4. Version of Record published: June 22, 2017 (version 2)

Copyright

© 2017, Zheng et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

Metrics

  • 2,126
    Page views
  • 349
    Downloads
  • 16
    Citations

Article citation count generated by polling the highest count across the following sources: Scopus, Crossref, PubMed Central.

Download links

A two-part list of links to download the article, or parts of the article, in various formats.

Downloads (link to download the article as PDF)

Open citations (links to open the citations from this article in various online reference manager services)

Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)

  1. Zhaoqing Zheng
  2. Ganesh Ambigapathy
  3. Joyce Keifer
(2017)
MeCP2 regulates Tet1-catalyzed demethylation, CTCF binding, and learning-dependent alternative splicing of the BDNF gene in Turtle
eLife 6:e25384.
https://doi.org/10.7554/eLife.25384

Further reading

    1. Computational and Systems Biology
    2. Neuroscience
    Emmanuelle Bioud et al.
    Research Article

    To decide whether a course of action is worth pursuing, individuals typically weigh its expected costs and benefits. Optimal decision-making relies upon accurate effort cost anticipation, which is generally assumed to be performed independently from goal valuation. In two experiments (n = 46), we challenged this independence principle of standard decision theory. We presented participants with a series of treadmill routes randomly associated to monetary rewards and collected both ‘accept’ versus ‘decline’ decisions and subjective estimates of energetic cost. Behavioural results show that higher monetary prospects led participants to provide higher cost estimates, although reward was independent from effort in our design. Among candidate cognitive explanations, they support a model in which prospective cost assessment is biased by the output of an automatic computation adjusting effort expenditure to goal value. This decision bias might lead people to abandon the pursuit of valuable goals that are in fact not so costly to achieve.

    1. Computational and Systems Biology
    2. Neuroscience
    Janus RL Kobbersmed et al.
    Research Article

    Synaptic communication relies on the fusion of synaptic vesicles with the plasma membrane, which leads to neurotransmitter release. This exocytosis is triggered by brief and local elevations of intracellular Ca2+ with remarkably high sensitivity. How this is molecularly achieved is unknown. While synaptotagmins confer the Ca2+ sensitivity of neurotransmitter exocytosis, biochemical measurements reported Ca2+ affinities too low to account for synaptic function. However, synaptotagmin's Ca2+ affinity increases upon binding the plasma membrane phospholipid PI(4,5)P2 and, vice versa, Ca2+-binding increases synaptotagmin's PI(4,5)P2 affinity, indicating a stabilization of the Ca2+/PI(4,5)P2 dual-bound syt. Here we devise a molecular exocytosis model based on this positive allosteric stabilization and the assumptions that (1.) synaptotagmin Ca2+/PI(4,5)P2 dual binding lowers the energy barrier for vesicle fusion and that (2.) the effect of multiple synaptotagmins on the energy barrier is additive. The model, which relies on biochemically measured Ca2+/PI(4,5)P2 affinities and protein copy numbers, reproduced the steep Ca2+ dependency of neurotransmitter release. Our results indicate that each synaptotagmin dual binding Ca2+/PI(4,5)P2 lowers the energy barrier for vesicle fusion by ~5 kBT and that allosteric stabilization of this state enables the synchronized engagement of several (typically three) synaptotagmins for fast exocytosis. Furthermore, we show that mutations altering synaptotagmin’s allosteric properties may show dominant-negative effects, even though synaptotagmins act independently on the energy barrier, and that dynamic changes of local PI(4,5)P2 (e.g. upon vesicle movement) dramatically impact synaptic responses. We conclude that allosterically stabilized Ca2+/PI(4,5)P2 dual binding enables synaptotagmins to exert their coordinated function in neurotransmission.