Skip to main content
bioRxiv
  • Home
  • About
  • Submit
  • ALERTS / RSS
Advanced Search
New Results

Identification and characterization of zebrafish Tlr4 co-receptor Md-2

Andrea N. Loes, Melissa N. Hinman, Dylan R. Farnsworth, Adam C. Miller, Karen Guillemin, View ORCID ProfileMichael J. Harms
doi: https://doi.org/10.1101/817528
Andrea N. Loes
1Institute of Molecular Biology, University of Oregon, Eugene, OR 97403
3Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR 97403
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Melissa N. Hinman
1Institute of Molecular Biology, University of Oregon, Eugene, OR 97403
4Department of Biology, University of Oregon, Eugene, OR 97403
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Dylan R. Farnsworth
2Institute of Neuroscience, University of Oregon, Eugene, OR 97403
4Department of Biology, University of Oregon, Eugene, OR 97403
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Adam C. Miller
2Institute of Neuroscience, University of Oregon, Eugene, OR 97403
4Department of Biology, University of Oregon, Eugene, OR 97403
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Karen Guillemin
1Institute of Molecular Biology, University of Oregon, Eugene, OR 97403
4Department of Biology, University of Oregon, Eugene, OR 97403
5Humans and the Microbiome Program, CIFAR, Toronto, Ontario M5G 1Z8, Canada
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Michael J. Harms
1Institute of Molecular Biology, University of Oregon, Eugene, OR 97403
3Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR 97403
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • ORCID record for Michael J. Harms
  • For correspondence: harms@uoregon.edu
  • Abstract
  • Full Text
  • Info/History
  • Metrics
  • Supplementary material
  • Preview PDF
Loading

ABSTRACT

The zebrafish (Danio rerio) is a powerful model organism for studies of the innate immune system. One apparent difference between human and zebrafish innate immunity is the cellular machinery for LPS-sensing. In amniotes, the protein complex formed by Toll-like receptor 4 and myeloid differentiation factor 2 (Tlr4/Md-2) recognizes the bacterial molecule lipopolysaccharide (LPS) and triggers an inflammatory response. It is believed that zebrafish have neither Md-2 nor Tlr4: Md-2 has not been identified outside of amniotes, while the zebrafish tlr4 genes appear to be paralogs, not orthologs, of amniote TLR4s. We revisited these conclusions. We identified a zebrafish gene encoding Md-2, ly96. Using single-cell RNA-Seq, we found that ly96 is transcribed in cells that also transcribe genes diagnostic for innate immune cells, including the zebrafish tlr4-like genes. Unlike amniote LY96, zebrafish ly96 expression is restricted to a small number of macrophage-like cells. In a functional assay, zebrafish Md-2 and Tlr4a form a complex that activates NF-κB signaling in response to LPS, but ly96 loss-of-function mutations gave little protection against LPS-toxicity in larval zebrafish. Finally, by analyzing the genomic context of tlr4 genes in eleven jawed vertebrates, we found that tlr4 arose prior to the divergence of teleosts and tetrapods. Thus, an LPS-sensitive Tlr4/Md-2 complex is likely an ancestral feature shared by mammals and zebrafish, rather than a de novo invention on the tetrapod lineage. We hypothesize that zebrafish retain an ancestral, low-sensitivity Tlr4/Md-2 complex that confers LPS-responsiveness to a specific subset of innate immune cells.

Footnotes

  • Funding sources: This research was funded by grants from the American Heart Association (AHA-15BGIA22830013, MJH) and the National Institutes of Health (NIH-T32GM007413, ANL, NIH-F32DK107318, MNH, P50GM09891, KG, NIH-R24OD026591, ACM). MJH is a Pew Scholar in the Biomedical Sciences, supported by The Pew Charitable Trusts. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Copyright 
The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-ND 4.0 International license.
Back to top
PreviousNext
Posted October 24, 2019.
Download PDF

Supplementary Material

Email

Thank you for your interest in spreading the word about bioRxiv.

NOTE: Your email address is requested solely to identify you as the sender of this article.

Enter multiple addresses on separate lines or separate them with commas.
Identification and characterization of zebrafish Tlr4 co-receptor Md-2
(Your Name) has forwarded a page to you from bioRxiv
(Your Name) thought you would like to see this page from the bioRxiv website.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Share
Identification and characterization of zebrafish Tlr4 co-receptor Md-2
Andrea N. Loes, Melissa N. Hinman, Dylan R. Farnsworth, Adam C. Miller, Karen Guillemin, Michael J. Harms
bioRxiv 817528; doi: https://doi.org/10.1101/817528
Digg logo Reddit logo Twitter logo Facebook logo Google logo LinkedIn logo Mendeley logo
Citation Tools
Identification and characterization of zebrafish Tlr4 co-receptor Md-2
Andrea N. Loes, Melissa N. Hinman, Dylan R. Farnsworth, Adam C. Miller, Karen Guillemin, Michael J. Harms
bioRxiv 817528; doi: https://doi.org/10.1101/817528

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
  • Tweet Widget
  • Facebook Like
  • Google Plus One

Subject Area

  • Immunology
Subject Areas
All Articles
  • Animal Behavior and Cognition (4092)
  • Biochemistry (8784)
  • Bioengineering (6490)
  • Bioinformatics (23376)
  • Biophysics (11761)
  • Cancer Biology (9163)
  • Cell Biology (13267)
  • Clinical Trials (138)
  • Developmental Biology (7420)
  • Ecology (11379)
  • Epidemiology (2066)
  • Evolutionary Biology (15109)
  • Genetics (10408)
  • Genomics (14017)
  • Immunology (9133)
  • Microbiology (22084)
  • Molecular Biology (8792)
  • Neuroscience (47417)
  • Paleontology (350)
  • Pathology (1421)
  • Pharmacology and Toxicology (2483)
  • Physiology (3709)
  • Plant Biology (8060)
  • Scientific Communication and Education (1433)
  • Synthetic Biology (2213)
  • Systems Biology (6019)
  • Zoology (1251)