Ciliary and extraciliary Gpr161 pools repress hedgehog signaling in a tissue-specific manner
- UT Southwestern Medical Center, United States
Abstract
The role of compartmentalized signaling in primary cilia during tissue morphogenesis is not well understood. The cilia-localized G-protein-coupled receptor—Gpr161 represses hedgehog pathway via cAMP signaling. We engineered a knock-in at Gpr161 locus in mice to generate a variant (Gpr161mut1), which was ciliary localization defective but cAMP signaling competent. Tissue phenotypes from hedgehog signaling depend on downstream bifunctional Gli transcriptional factors functioning as activators/repressors. Compared to knockout (ko), Gpr161mut1/ko had delayed embryonic lethality, moderately increased hedgehog targets and partially down-regulated Gli3-repressor. Unlike ko, the Gpr161mut1/ko neural tube did not show Gli2-activator-dependent expansion of ventral-most progenitors. Instead, the intermediate neural tube showed progenitor expansion that depends on loss of Gli3-repressor. Increased extraciliary receptor (Gpr161mut1/mut1) prevented ventralization. Morphogenesis in limb buds and midface requires Gli-repressor; these tissues in Gpr161mut1/mut1 manifested hedgehog hyperactivation phenotypes—polydactyly and midfacial widening. Thus, ciliary and extraciliary Gpr161 pools likely establish tissue-specific Gli-repressor thresholds in determining morpho-phenotypic outcomes.
Data availability
All data generated or analyzed during this study are included in the manuscript and supporting files. All information on replicates is provided in figure legends. Most data are shown as scatter plots. In places where data means are provided, we have also added source data for Figure 4C, Figure 6D and Figure 4-supplement 1. No embryos or samples were excluded from analysis.
Article and author information
Author details
Saikat Mukhopadhyay
Funding
Alex's Lemonade Stand Foundation for Childhood Cancer (A-grant)
- Saikat Mukhopadhyay
National Institute of General Medical Sciences (1R01GM113023)
- Saikat Mukhopadhyay
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 the animals in the study were handled according to protocols approved by the UT Southwestern Institutional Animal Care and Use Committee, and the mouse colonies were maintained in a barrier facility at UT Southwestern, in agreement with the State of Texas legal and ethical standards of animal care. protocol 2016-101516
Copyright
© 2021, Hwang 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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Ciliary and extraciliary Gpr161 pools repress hedgehog signaling in a tissue-specific manner
eLife 10:e67121.
https://doi.org/10.7554/eLife.67121
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