The involvement of cAMP signaling pathway in axis specification in Xenopus embryos.
The cAMP signaling system has been postulated to be involved in embryogenesis of many animal species, however, little is known about its role in embryonic axis formation in vertebrates. In this study, the role of the cAMP signaling pathway in patterning the body plan of the Xenopus embryo was investigated by expressing and activating the exogenous human 5-hydroxytryptamine type 1a receptor (5-HT(1a)R) which inhibits adenylyl cyclase through inhibitory G-protein in embryos in a spatially- and temporally-controlled manner. In embryos, ventral, but not dorsal expression and stimulation of this receptor during blastula and gastrula stages induced secondary axes but were lacking anterior structures. At the molecular level, 5-HT(1a)R stimulation induced expression of the dorsal mesoderm marker genes, and downregulated expression of the ventral markers but had no effect on expression of the pan mesodermal marker gene in ventral marginal zone explants. In addition, ventral expression and stimulation of the receptor partially restored dorsal axis of UV-irradiated axis deficient embryo. Finally, the total mass of cAMP differs between dorsal and ventral regions of blastula and gastrula embryos and this is regulated in a temporally-specific manner. These results suggest that the cAMP signaling system may be involved in the transduction of ventral signals in patterning early embryos.
Kim
M J
MJ
Department of Life Science, Pohang University of Science and Technology, San 31 Hyoja-Dong, Pohang, Kyungbuk, South Korea.
Han
J K
JK
D000818:Animals; D001755:Blastocyst / Q000378:metabolism; D019521:Body Patterning / Q000502:physiology*; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000235:genetics; D002352:Carrier Proteins; D000242:Cyclic AMP / Q000378:metabolism*; D015536:Down-Regulation; D004625:Embryo, Nonmammalian / Q000378:metabolism / Q000528:radiation effects; D005260:Female; D018507:Gene Expression Regulation, Developmental; D005819:Genetic Markers; D006023:Glycoproteins; D051956:Goosecoid Protein; D018398:Homeodomain Proteins / Q000235:genetics / Q000528:radiation effects; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D011506:Proteins / Q000235:genetics / Q000528:radiation effects; D011518:Proto-Oncogene Proteins / Q000235:genetics; D011985:Receptors, Serotonin / Q000235:genetics* / Q000378:metabolism; D044263:Receptors, Serotonin, 5-HT1; D012097:Repressor Proteins; D015398:Signal Transduction; D014157:Transcription Factors; D014466:Ultraviolet Rays; D051153:Wnt Proteins; D029867:Xenopus Proteins; D014982:Xenopus laevis / Q000196:embryology*; D029961:Zebrafish Proteins; D000099176:Noggin Protein
D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D002352:Carrier Proteins; D000242:Cyclic AMP; D005819:Genetic Markers; D006023:Glycoproteins; D051956:Goosecoid Protein; D018398:Homeodomain Proteins; D036341:Intercellular Signaling Peptides and Proteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D011985:Receptors, Serotonin; D044263:Receptors, Serotonin, 5-HT1; D012097:Repressor Proteins; D014157:Transcription Factors; D051153:Wnt Proteins; D029867:Xenopus Proteins; D029961:Zebrafish Proteins; D000099176:Noggin Protein; C525809:BMP4 protein, human; C093133:SIA1 protein, Xenopus; C525812:bmp4 protein, Xenopus; C525813:bmp4 protein, zebrafish; C109693:ventx1.1 protein, Xenopus; C099992:ventx2.1 protein, Xenopus; C054234:chordin