Xenopus marginal coil (Xmc), a novel FGF inducible cytosolic coiled-coil protein regulating gastrulation movements.
Gastrulation in vertebrates is a highly dynamic process driven by convergent extension movements of internal mesodermal cells, under the regulatory activity of the Spemann-Mangold or gastrula organizer. In a large-scale screen for genes expressed in the organizer, we have isolated a novel gene, termed Xmc, an acronym for Xenopus marginal coil. Xmc encodes a protein containing two widely spaced evolutionarily non-conserved coiled coils. Xmc protein is found in vesicular aggregates in the cytoplasm and associated with the inner plasma membrane. We show that Xmc is expressed in a dynamic fashion around the blastoporal circumference, in mesodermal cells undergoing morphogenetic movements, in a pattern similar to FGF target genes. Likewise, Xmc expression can be induced by ectopic XeFGF signaling and the early mesodermal expression is dependent on FGF receptor-mediated signaling. Morpholino-mediated translational 'knock-down' of Xmc results in embryos that display a reduced elongation of the antero-posterior axis and in a pronounced inhibition of morphogenetic movements in embryos and dorsal marginal zone explants. Xmc loss-of-function does not interfere with mesoderm induction or maintenance per se. Our results suggest that Xmc is a novel FGF target gene that is required for morphogenetic movements during gastrulation in Xenopus.
Frazzetto
Giovanni
G
Developmental Biology Programme, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, D-69117, Heidelberg, Germany. frazzett@embl-heidelberg.de
Klingbeil
Pamela
P
Bouwmeester
Tewis
T
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D005346:Fibroblast Growth Factors / Q000378:metabolism; D005775:Gastrula / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D015723:Gene Library; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000737:chemistry* / Q000235:genetics; D008648:Mesoderm / Q000502:physiology; D008856:Microscopy, Fluorescence; D008957:Models, Genetic; D010957:Plasmids / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013997:Time Factors; D014981:Xenopus; D029867:Xenopus Proteins / Q000096:biosynthesis* / Q000737:chemistry* / Q000235:genetics
D008565:Membrane Proteins; D029867:Xenopus Proteins; C466101:Xmc protein, Xenopus; D005346:Fibroblast Growth Factors