Roles of Xenopus chemokine ligand CXCLh (XCXCLh) in early embryogenesis

Abstract

Several chemokine molecules control cell movements during early morphogenesis. However, it is unclear whether chemokine molecules affect cell fate. Here, we identified and characterized the CXC-type chemokine ligand in Xenopus laevis, Xenopus CXCLh (XCXCLh), during early embryogenesis. XCXCLh is expressed in the dorsal vegetal region at the gastrula stage. Both overexpression and knockdown of XCXCLh in the dorsal region inhibited gastrulation. XCXCLh contributed to the attraction of mesendodermal cells and accelerated the reassembly of scratched culture cells. Also, XCXCLh contributed to early endodermal induction. Overexpression of VegTmRNA or high concentrations of calcium ions induced XCXCLh expression. XCXCLh may play roles in both cell movements and differentiation during early Xenopus embryogenesis.

ccr7 affects both morphogenesis and differentiation during early Xenopus embryogenesis

“…The Cxcl12–Cxcr4‐signaling axis serves important roles in primordial germ cell migration and neural crest chemotaxis in Xenopus and zebrafish (Doitsidou et al, 2002; Takeuchi et al, 2010; Theveneau et al, 2010). In addition, cxcl12 is related to somite morphogenesis in Xenopus (Leal et al, 2014), and cxcl11 plays an important role in endodermal induction in Xenopus (Goto et al, 2018).…”

Preparation of three‐notochord explants for imaging analysis of the cell movements of convergent extension during early Xenopus morphogenesis

“…Mediolateral cell intercalation is, in turn, driven by bipolar, mediolaterally directed protrusive activity and cell‐on‐cell traction (Domingo & Keller, 1995; Keller et al., 2000; Keller & Sutherland, 2020; Shih & Keller, 1992a, 1992b). This cell polarity is affected by many factors, including molecules in the noncanonical Wnt/planar cell polarity (PCP) pathway, the small GTPases and related molecules (Choi & Han, 2002; Goto et al., 2005; Goto & Keller, 2002; Kim & Han, 2005; Popov et al., 2018), molecular signaling and structural effects of fibrils of extracellular matrices (Davidson et al., 2008; Goto et al., 2005; Skoglund & Keller, 2007), the dependence of PCP signaling on fibronectin–integrin signaling (Davidson et al., 2006), chemokine molecules (Goto & Asashima, 2011; Goto et al., 2013, 2018), and cytoskeletal molecules (Bonacci et al., 2012; Pfister et al., 2016; Rolo et al., 2009; Skoglund et al., 2008). When CE movements were inhibited by loss of cell polarity, embryos had very short axes and widely opened neural folds (Goto & Asashima, 2011; Goto & Keller, 2002).…”

“…Thus, three‐notochord explants are useful for analyzing the tissue‐level movements of CT and the motile behavior of the intercalating cells simultaneously. Although three‐notochord explants have been used to analyze the CE and the individual cell behaviors in previous studies (Goto & Asashima, 2011; Goto et al., 2005, 2018), the details of the experimental method have not been described.…”

“…the small GTPases and related molecules (Choi & Han, 2002;Goto et al, 2005;Goto & Keller, 2002;Kim & Han, 2005;Popov et al, 2018), molecular signaling and structural effects of fibrils of extracellular matrices (Davidson et al, 2008;Goto et al, 2005;Skoglund & Keller, 2007), the dependence of PCP signaling on fibronectin-integrin signaling (Davidson et al, 2006), chemokine molecules (Goto & Asashima, 2011;Goto et al, 2013Goto et al, , 2018, and cytoskeletal molecules (Bonacci et al, 2012;Pfister et al, 2016;Rolo et al, 2009;Skoglund et al, 2008). When CE movements were inhibited by loss of cell polarity, embryos had very short axes and widely opened neural folds (Goto & Asashima, 2011;Goto & Keller, 2002).…”

“…Thus, three-notochord explants are useful for analyzing the tissue-level movements of CT and the motile behavior of the intercalating cells simultaneously. Although threenotochord explants have been used to analyze the CE and the individual cell behaviors in previous studies (Goto & Asashima, 2011;Goto et al, 2005Goto et al, , 2018, the details of the experimental method have not been described. Three-notochord explants are made by placing notochords labeled with different fluorescent colors in an alternate pattern, like red-green-red, thereby providing the contrast to distinguish the intercalating cells from one another, which is necessary to resolve protrusive activity and individual cell behavior.…”