CRISPR Screens Uncover Genes that Regulate Target Cell Sensitivity to the Morphogen Sonic Hedgehog

Dev Cell. 2018 Jan 8;44(1):113-129.e8. doi: 10.1016/j.devcel.2017.12.003. Epub 2017 Dec 28.

Abstract

To uncover regulatory mechanisms in Hedgehog (Hh) signaling, we conducted genome-wide screens to identify positive and negative pathway components and validated top hits using multiple signaling and differentiation assays in two different cell types. Most positive regulators identified in our screens, including Rab34, Pdcl, and Tubd1, were involved in ciliary functions, confirming the central role for primary cilia in Hh signaling. Negative regulators identified included Megf8, Mgrn1, and an unannotated gene encoding a tetraspan protein we named Atthog. The function of these negative regulators converged on Smoothened (SMO), an oncoprotein that transduces the Hh signal across the membrane. In the absence of Atthog, SMO was stabilized at the cell surface and concentrated in the ciliary membrane, boosting cell sensitivity to the ligand Sonic Hedgehog (SHH) and consequently altering SHH-guided neural cell-fate decisions. Thus, we uncovered genes that modify the interpretation of morphogen signals by regulating protein-trafficking events in target cells.

Keywords: CRISPR screen; Hedgehog signaling; Smoothened; ciliopathy; congenital heart disease; heterotaxy; morphogen signaling; neural tube patterning; primary cilia; protein trafficking.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Movement / drug effects
  • Cilia / drug effects
  • Cilia / physiology*
  • Clustered Regularly Interspaced Short Palindromic Repeats*
  • Fluorescence
  • Hedgehog Proteins / pharmacology*
  • Membrane Proteins / metabolism
  • Mice
  • NIH 3T3 Cells
  • Neurons / cytology
  • Neurons / drug effects
  • Neurons / physiology*
  • Signal Transduction / drug effects*
  • Smoothened Receptor / genetics
  • Smoothened Receptor / metabolism*

Substances

  • Hedgehog Proteins
  • Membrane Proteins
  • Smo protein, mouse
  • Smoothened Receptor