The PCP protein Vangl2 regulates migration of hindbrain motor neurons by acting in floor plate cells, and independently of cilia function

Abstract

Vangl2, a core component of the Planar Cell Polarity pathway, is necessary for the caudal migration of Facial Branchiomotor (FBM) neurons in the vertebrate hindbrain. Studies in zebrafish suggest that vangl2 functions largely non-cell autonomously to regulate FBM neuron migration out of rhombomere 4 (r4), but the cell-type within which it acts is not known. Here, we demonstrate that vangl2 functions largely in floor plate cells to regulate caudal neuronal migration. Furthermore, FBM neurons fail to migrate caudally in the mouse Gli2 mutant that lacks the floor plate, suggesting an evolutionarily conserved role for this cell type in neuronal migration. Although hindbrain floor plate cilia are disorganized in vangl2 mutant embryos, cilia appear to be dispensable for neuronal migration. Notably, Vangl2 is enriched in the basolateral, but not apical, membranes of floor plate cells. Taken together, our data suggest strongly that Vangl2 regulates FBM neuron migration by acting in floor plate cells, independently of cilia function.

Structural and temporal requirements of Wnt/PCP protein Vangl2 function for convergence and extension movements and facial branchiomotor neuron migration in zebrafish

“…Zebrafish vangl2 is broadly expressed during gastrulation stages, and in the nervous system and adjacent tissues during somitogenesis stages (Park and Moon, 2002; Sittaramane et al, 2013). In vitro transcribed mRNAs for the different constructs were injected into zebrafish embryos to examine potential gain-of-function phenotypes during CE movements of gastrulation (Fig.…”

“…Vangl2 is a four-pass membrane-spanning protein with the N-terminal and C-terminal domains located in the cytosol, with a PDZ domain-binding motif (PBM) at the C-terminus (Katoh, 2002b; Park and Moon, 2002; Darken et al, 2002). In zebrafish, vangl2 is broadly expressed during gastrulation stages, and in the nervous system and adjacent tissues during somitogenesis stages (Park and Moon, 2002; Sittaramane et al, 2013). In vertebrates, Vangl2 is necessary for several developmental and physiological processes, including cell proliferation and fate determination (Lake and Sokol, 2009), polarized cell movements such as convergence and extension (CE) movements during gastrulation (Marlow et al, 1998; Jessen et al, 2002; Darken et al, 2002; Torban et al, 2004) and FBM neuron migration (Bingham et al, 2002; Jessen et al, 2002: Vivancos et al, 2009; Glasco et al, 2012), wound repair (Caddy et al, 2010), branching morphogenesis in kidney and lung (Yates et al, 2010a, b), reproductive tract development (Vandenberg and Sassoon, 2009), tumor cell migration (Katoh, 2005; Coyle et al, 2008; Cantrell and Jessen, 2010), hair follicle development (Devenport and Fuchs, 2008), and orientation of cilia in many tissues and organs (Borovina et al, 2010; May-Simera, et al, 2010; Montcouoquiol et al, 2006; Song et al, 2010; Tissir et al, 2010).…”

Planar cell polarity in moving cells: think globally, act locally

“…As is the case for other cell migration and axon guidance events that involve PCP, signaling is required within the migrating cells themselves (Davey et al, 2016;Jessen et al, 2002;Walsh et al, 2011). However, chimeric analysis in zebrafish has demonstrated an equally important non-cell-autonomous role for Vangl2, Fzd3a, Celsr2 and Scrib, as wild-type FBMNs fail to migrate through a neuroepithelium that is mutant for any of these factors (Davey et al, 2016;Jessen et al, 2002;Sittaramane et al, 2013;Wada et al, 2005Wada et al, , 2006Walsh et al, 2011). It should also be noted that cells of both the neuroepithelium and the floorplate exhibit planar polarization along their AP axes that depends on the same PCP core components that are required for FBMN migration; these factors exhibit canonical epithelial localization, with Vangl-Pk opposite Fzd-Dvl along the axis of polarization (Borovina et al, 2010;Ciruna et al, 2006;Davey et al, 2016;Walsh et al, 2011).…”

Dynamic intracellular distribution of Vangl2 during cell polarization in zebrafish gastrula

“…Second, we adopted the mosaic approach that allows the visualization of protein distribution asymmetries on single anterior or posterior membranes using a transgenic line expressing a zebrafish GFP-Vangl2 N-terminal fusion protein (Sittaramane et al, 2013). We transplanted a few cells from Tg(vangl2:GFP-Vangl2) embryos injected with mCherry synthetic mRNA (used as a control) into unlabeled WT host embryos.…”

“…Naturally spawned embryos were raised at 28-32°C and staged by morphology (Kimmel et al, 1995). Tg(vangl2:GFPVangl2) fish were a gift from Anand Chandrasekhar (University of Missouri, Columbia, MO, USA) (Sittaramane et al, 2013). MZvangl2 vu67/vu67 fish were obtained by germ cell transplantation as described by Ciruna et al (2002).…”