Genetic Analysis Reveals a Hierarchy of Interactions between Polycystin-Encoding Genes and Genes Controlling Cilia Function during Left-Right Determination
| Autor: | Maria T. Buenavista, Surya M. Nauli, Saloni H. Patel, Hiroshi Hamada, Debbie Williams, Dominic P. Norris, Jennifer L. Keynton, Xingjian Jin, Daniel T. Grimes, Rohanah Hussain, Jennifer Vibert, Shinohara Kyosuke |
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| Přispěvatelé: | Barsh, Gregory S. |
| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Embryology Cancer Research Heredity Social Sciences Nodal signaling Mesoderm Mice 0302 clinical medicine Stereochemistry Psychology Genetics (clinical) Genetics Regulation of gene expression Mice Inbred C3H Physics Cilium Classical Mechanics Gene Expression Regulation Developmental Cell biology Phenotypes Chemistry medicine.anatomical_structure Physical Sciences Intercellular Signaling Peptides and Proteins Sensory Perception Cellular Structures and Organelles Research Article Gene Flow TRPP Cation Channels lcsh:QH426-470 Nodal Protein Epistasis and functional genomics Mice Transgenic Fluid Mechanics Biology Continuum Mechanics 03 medical and health sciences Isomerism medicine Point Mutation Animals Cilia Fluid Flow Molecular Biology Ecology Evolution Behavior and Systematics Body Patterning Evolutionary Biology Population Biology Mechanosensation Lateral plate mesoderm Embryos Biology and Life Sciences Membrane Proteins Fluid Dynamics Cell Biology Embryo Mammalian Protein Structure Tertiary lcsh:Genetics 030104 developmental biology Mutation NODAL Population Genetics 030217 neurology & neurosurgery Developmental Biology Neuroscience |
| Zdroj: | PLoS Genetics PLoS Genetics, Vol 12, Iss 6, p e1006070 (2016) |
| ISSN: | 1553-7404 |
| DOI: | 10.1371/journal.pgen.1006070 |
| Popis: | During mammalian development, left-right (L-R) asymmetry is established by a cilia-driven leftward fluid flow within a midline embryonic cavity called the node. This ‘nodal flow’ is detected by peripherally-located crown cells that each assemble a primary cilium which contain the putative Ca2+ channel PKD2. The interaction of flow and crown cell cilia promotes left side-specific expression of Nodal in the lateral plate mesoderm (LPM). Whilst the PKD2-interacting protein PKD1L1 has also been implicated in L-R patterning, the underlying mechanism by which flow is detected and the genetic relationship between Polycystin function and asymmetric gene expression remains unknown. Here, we characterize a Pkd1l1 mutant line in which Nodal is activated bilaterally, suggesting that PKD1L1 is not required for LPM Nodal pathway activation per se, but rather to restrict Nodal to the left side downstream of nodal flow. Epistasis analysis shows that Pkd1l1 acts as an upstream genetic repressor of Pkd2. This study therefore provides a genetic pathway for the early stages of L-R determination. Moreover, using a system in which cultured cells are supplied artificial flow, we demonstrate that PKD1L1 is sufficient to mediate a Ca2+ signaling response after flow stimulation. Finally, we show that an extracellular PKD domain within PKD1L1 is crucial for PKD1L1 function; as such, destabilizing the domain causes L-R defects in the mouse. Our demonstration that PKD1L1 protein can mediate a response to flow coheres with a mechanosensation model of flow sensation in which the force of fluid flow drives asymmetric gene expression in the embryo. Author Summary Vertebrates exhibit left-right (L-R) asymmetry in positioning and patterning their internal organs and associated vasculature; abnormal L-R asymmetry can result in birth defects such as congenital heart disease. The earliest known event in mammalian L-R patterning is a leftward fluid flow across a transient embryonic structure termed the node. This ‘nodal flow’ is driven by the action of motile cilia, hair-like organelles protruding from the cell surface within the node. Nodal flow is sensed by crown cells that surround the node; this requires immotile primary cilia and the putative cation channel Polycystin-2 (PKD2). A second Polycystin protein, PKD1L1, is implicated in this pathway. We describe two principle findings: a genetic hierarchy in cilia-motility genes act upstream of Polycystin-encoding genes and in which Pkd1l1 acts upstream of, and likely represses Pkd2. We further demonstrate that PKD1L1 is sufficient to mediate a flow-induced Ca2+ response in cultured cells, and that an extracellular PKD domain is critical for both flow detection and proper L-R patterning. Together, these findings reveal a genetic pathway operating at the level of flow sensation and demonstrate that PKD1L1 is able to act to elicit flow-induced Ca2+ signals, thereby supporting the mechanosensation model of nodal flow sensation. |
| Databáze: | OpenAIRE |
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