Local activation of protein kinase A inhibits morphogenetic movements during Xenopus gastrulation.
cAMP-dependent protein kinase (PKA) has various biological roles in many organisms. However, little is known about its role in the developmental processes of vertebrates. In this study, we describe the functional analysis of PKA during gastrulation movements in Xenopus laevis. Overexpression of constitutively active PKA (cPKA) in the dorsal equatorial region of the embryo affects morphogenetic movement during gastrulation. We also show that intrinsic differences of PKA activities along the dorsoventral axis are set up and the level of PKA activity on the dorsal region is lower than that on the ventral region from late blastula to gastrula stages. In addition, PKA activation in animal explants inhibits activin-induced elongation. In cPKA-injected embryos, there were no changes in the expressions of markers involved in mesoderm specification, although the correct expression domains of these genes were altered. The effects of PKA activation can be restored by coexpression of PKI, a pseudosubstrate of PKA. We further analyzed the effects of PKA activation on the behavior of migratory gastrulating cells in vitro. Expression of cPKA in head mesoderm cells causes less polarized and/or randomized migration as demonstrated by a directional cell migration assay. Finally, we show that RhoA GTPase lies downstream of PKA, affecting activin-induced convergent extension movements. Taken together, these results suggest that overexpressed PKA can modulate a pathway responsible for morphogenetic movements during Xenopus gastrulation.
Song
Byung-Ho
BH
Division of Molecular and Life Sciences, Pohang University of Science and Technology, San 31, Hyoja Dong, Pohang, Kyungbuk, South Korea.
Choi
Sun-Cheol
SC
Han
Jin-Kwan
JK
D000818:Animals; D015415:Biomarkers; D019521:Body Patterning; D002465:Cell Movement / Q000502:physiology*; D016764:Cell Polarity; D046508:Culture Techniques; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation; D005353:Fibronectins / Q000378:metabolism; D017403:In Situ Hybridization; D008648:Mesoderm / Q000502:physiology; D008845:Microinjections; D009024:Morphogenesis / Q000502:physiology*; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D014982:Xenopus laevis / Q000196:embryology* / Q000502:physiology
D015415:Biomarkers; D005353:Fibronectins; D010446:Peptide Fragments; D017868:Cyclic AMP-Dependent Protein Kinases