1. Chromosomes and Gene Expression
  2. Developmental Biology
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Multi-enhancer transcriptional hubs confer phenotypic robustness

  1. Albert Tsai  Is a corresponding author
  2. Mariana R P Alves
  3. Justin Crocker
  1. European Molecular Biology Laboratory, Germany
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Cite this article as: eLife 2019;8:e45325 doi: 10.7554/eLife.45325

Abstract

We previously showed in Drosophila melanogaster embryos that low-affinity Ultrabithorax (Ubx)-responsive shavenbaby (svb) enhancers drive expression using localized transcriptional environments and that active svb enhancers on different chromosomes tended to colocalize (Tsai et al., 2017). Here, we test the hypothesis that these multi-enhancer 'hubs' improve phenotypic resilience to stress by buffering against decreases in transcription factor concentrations and transcriptional output. Deleting a redundant enhancer from the svb locus led to reduced trichome numbers in embryos raised at elevated temperatures. Using high-resolution fluorescence microscopy, we observed lower Ubx concentration and transcriptional output in this deletion allele. Transcription sites of the full svb cis-regulatory region inserted into a different chromosome colocalized with the svb locus, increasing Ubx concentration, the transcriptional output of svb, and partially rescuing the phenotype. Thus, multiple enhancers could reinforce a local transcriptional hub to buffer against environmental stresses and genetic perturbations, providing a mechanism for phenotypical robustness.

Data availability

The original images (cuticle preparations and embryo images, organized into zip files) are available for download and are indexed at: https://www.embl.de/download/crocker/svb_enhancer_colocalization/index.html. Please note that the raw AiryScan images must be processed though the Zen software from Zeiss before they can be opened/analyzed using standard image processing softwares. These files are large, totaling up to approximately 180 GB in size. We can also send these files directly if a means of transfer (hard drives, etc.) is provided.

Article and author information

Author details

  1. Albert Tsai

    Department of Developmental Biology, European Molecular Biology Laboratory, Heidelberg, Germany
    For correspondence
    albert.tsai@embl.de
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-1643-0780
  2. Mariana R P Alves

    Department of Developmental Biology, European Molecular Biology Laboratory, Heidelberg, Germany
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-0796-2101
  3. Justin Crocker

    Department of Developmental Biology, European Molecular Biology Laboratory, Heidelberg, Germany
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-5113-0476

Funding

Damon Runyon Cancer Research Foundation (DRG 2220-15)

  • Albert Tsai

European Molecular Biology Organization

  • Albert Tsai
  • Mariana R P Alves
  • Justin Crocker

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

Reviewing Editor

  1. David N Arnosti, Michigan State University, United States

Publication history

  1. Received: February 27, 2019
  2. Accepted: July 8, 2019
  3. Accepted Manuscript published: July 11, 2019 (version 1)
  4. Version of Record published: July 23, 2019 (version 2)

Copyright

© 2019, Tsai 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.

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