Cdc42 GTPase and Rac1 GTPase act downstream of p120 catenin and require GTP exchange during gastrulation of zebrafish mesoderm

Abstract

Background: We investigated the roles of p120 catenin, Cdc42, Rac1, and RhoA GTPases in regulating migration of presomitic mesoderm cells in zebrafish embryos. p120 catenin has dual roles: It binds the intracellular and juxtamembrane region of cadherins to stabilize cadherin-mediated adhesion with the aid of RhoA GTPase, and it activates Cdc42 GTPase and Rac1 GTPase in the cytosol to initiate cell motility. Results: During gastrulation of zebrafish embryos, knockdown of the synthesis of zygotic p120 catenind1 mRNAs with a splice-site morpholino caused lateral widening and anterior-posterior shortening of the presomitic mesoderm and somites and a shortened anterior-posterior axis. These phenotypes indicate a cell-migration effect. Co-injection of low amounts of wild-type Cdc42 or wild-type Rac1 or dominant-negative RhoA mRNAs, but not constitutively-active Cdc42 mRNA, rescued these p120 catenin d1-depleted embryos. Conclusions: These downstream small GTPases require appropriate spatiotemporal stimulation or cycling of GTP to guide mesodermal cell migration. A delicate balance of Rho GTPases and p120 catenin underlies normal development. Developmental Dynamics 241:1545-1561, 2012. V C 2012 Wiley Periodicals Inc.Key words: p120 Catenin (CTNND1); ARVCF; Delta-catenin (CTNND2b); Cdc42 GTPase; Rac1 GTPase, RhoA GTPase; gastrulation; presomitic mesoderm; somites; zebrafish Key findings p120 catetin is required for extension of the dorsal axis and normal migration of the presomitic mesoderm. Cdc42 and Rac1 GTPases are downstream of p120 catenin d1 signaling and require exchange of GTP for GDP. Local stimulation of the exchange of GTP for GDP in Cdc42 and Rac GTPases mediates directional migration of the presomitic mesoderm. A balance of the amount of p120 catenin d1 and localized activation or turnover of Cdc42, Rac1, and Rho GTPase are required for normal zebrafish cell migration. Accepted 31 July 2012 Developmental DynamicsABBREVIATIONS Ab antibody ARVCF armadillo repeat gene deleted in velo-cardio-facial syndrome CA constitutively active Chr chromosome C(t) relative amount of RT-PCR product hpf hours post-fertilization DN dominant negative d1 splice-MO antisense morpholino oligonucleotide to the 12 th splice site of zebrafish p120 catenin d1 p120 catenin d1 (CTNND1) also called p120 catenin, Xenopus p120 catenin is a CTNND1 p120 catenin d2b (CTNND2b) also called Delta-catenin Rok1 Rho kinase1 RT reverse transcriptase minus-RT controls without reverse transcriptase qRT-PCR quantitative real-time PCR WT wild-type Xp120 catenin mRNA Xenopus p120 catenin d1 mRNA.Additional Supporting Information may be found in the online version of this article.

Epistemology of the origin of cancer: a new paradigm

“…This process may be seen as the starting point for the chronic-stress escape strategy. The p120 accumulation stimulates Cdc42 - a cell-division control protein and a member of the family of Rho small guanosine triphosphatases (GTPases) - and activates Ras-related C3 botulinum toxin substrate 1 (Rac1), decreasing thereby E-cadherin [179,180], microtubule polymerization [181], and integrin clustering [182]. Thus, the contact to the basal membrane is destabilized [183], promoting cell migration.…”

A GAL4‐inducible transgenic tool kit for the in vivo modulation of Rho GTPase activity in zebrafish

“…Zebrafish provide an excellent model for investigation of the molecular function of vertebrate Rho GTPases in vivo (Kardash et al, ; Lai et al, ; Salas‐Vidal et al, ; Zhu et al, ). Previous studies of Rho GTPase function in developing zebrafish employed microinjection of mRNA to drive global overexpression of wild‐type, constitutively active, or dominant negative versions (Hsu et al, ; Xu et al, ; Yeh et al, ; Zhu et al, , Zhu et al, ), or morpholino oligos for transient disruption of Rho GTPase expression (Hsu et al, ; Srinivas et al, ). Due to the central role of Rho GTPases in early embryogenesis, approaches that modulate global Rho GTPase activity must focus on events occurring very early during zebrafish development, and thus have not been effective in analyzing the functions of these proteins during later developmental events.…”

“…Analysis of Rho GTPase activity and function in vivo therefore requires experimental approaches that allow modulation of activity in specific tissues or cell populations, and at specific time points (Chew et al, 2014;Govek et al, 2005;Heasman and Ridley, 2008;Heynen et al, 2013;Jackson et al, 2011;Luo et al, 1996;Ruchhoeft and Ohnuma, 1999;Wong and Faulkner-Jones, 2000;Xiang and Vanhoutte, 2011 Zebrafish provide an excellent model for investigation of the molecular function of vertebrate Rho GTPases in vivo (Kardash et al, 2010;Lai et al, 2005;Salas-Vidal et al, 2005;Zhu et al, 2006). Previous studies of Rho GTPase function in developing zebrafish employed microinjection of mRNA to drive global overexpression of wild-type, constitutively active, or dominant negative versions (Hsu et al, 2012;Xu et al, 2014;Yeh et al, 2011;Zhu et al, 2008, Zhu et al, 2006, or morpholino oligos for transient disruption of Rho GTPase expression (Hsu et al, 2012;Srinivas et al, 2007). Due to the central role of Rho GTPases in early embryogenesis, approaches that modulate global Rho GTPase activity must focus on events occurring very early during zebrafish development, and thus have not been effective in analyzing the functions of these proteins during later developmental events.…”

ARVCF expression is significantly correlated with the malignant phenotype of non‐small cell lung cancer

“…Members of the p120ctn subfamily, such as p120ctn and δ‐catenin, promote the malignant phenotype of lung cancer by regulating the activity of small GTPases such as RhoA ; we speculated that ARVCF plays the same role. RhoA is a core member of the Rho GTPase family and a Rho GTP‐binding protein of the Ras super‐family that alternates between activated (GTP‐bound) and inactivated (GDP‐bound) states.…”