A novel, activin-inducible, blastopore lip-specific gene of Xenopus laevis contains a fork head DNA-binding domain.
The organizer region, or dorsal blastopore lip, plays a central role in the initiation of gastrulation and the formation of the body axis during Xenopus development. A similar process can also be induced in ectodermal explants by activin or by injection of activin mRNA into embryos. We have searched early embryo-specific cDNA libraries for genes containing the fork head box sequence that encodes a DNA-binding domain similar to that of the Drosophila homeotic gene fork head and rat hepatocyte nuclear factor HFN3 beta. These genes were subsequently tested for expression in the organizer region of blastula/gastrula-stage embryos as well as inducibility by activin. Our effort resulted in the isolation of a gene, XFKH1, that is primarily expressed in the dorsal blastopore lip of early gastrulae and is inducible by activin. At later stages it is expressed in the notochord and neural floor plate. Because of its spatial and temporal expression pattern, as well as its inducibility by activin, this gene is a good candidate to have a regulatory function in the initial processes of axis formation in Xenopus laevis embryos.
Dirksen
M L
ML
Laboratory of Molecular Pharmacology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland 20892.
Jamrich
M
M
D028341:Activins; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D004268:DNA-Binding Proteins / Q000235:genetics*; D004625:Embryo, Nonmammalian / Q000378:metabolism; D051858:Forkhead Transcription Factors; D007265:Inhibins / Q000494:pharmacology*; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics; D029867:Xenopus Proteins; D014982:Xenopus laevis / Q000196:embryology / Q000235:genetics*
D004268:DNA-Binding Proteins; D051858:Forkhead Transcription Factors; C000598904:FoxA4 protein, Xenopus; D012333:RNA, Messenger; D014157:Transcription Factors; D029867:Xenopus Proteins; D028341:Activins; D007265:Inhibins