XHNF1β is a homeobox-containing gene initially expressed at the blastula stage in the vegetal part of the Xenopus embryo. We investigated its early role by functional ablation, through mRNA injection of an XHNF1β/engrailed repressor fusion construct (XHNF1β/EngR). Dorsal injections of XHNF1β/EngR mRNA abolish dorsal mesoderm formation, leading to axial deficiencies; ventral injections disrupt ventral mesoderm formation without affecting axial development. XHNF1β/EngR phenotypic effects specifically depend on the DNA-binding activity of its homeodomain and are fully rescued by coinjection of XHNF1β mRNA. Vegetal injection of XHNF1β/EngR mRNA blocks the mesoderm-inducing ability of vegetal explants, Both B-Vg1 and VegT maternal determinants trigger XHNF1β expression in animal caps. XHNF1β/EngR mRNA blocks B-Vg1-mediated, but not by eFGF-mediated, mesoderm induction in animals caps. However, wild-type XHNF1β mRNA does not trigger Xbra expression in animal caps. We conclude that XHNF1β function is essential, though not sufficient, for mesoderm induction in the Xenopus embryo.
HNF1b is required for mesoderm induction in the Xenopus embryo
VIGNALI, ROBERT;BARSACCHI, GIUSEPPINA
2000-01-01
Abstract
XHNF1β is a homeobox-containing gene initially expressed at the blastula stage in the vegetal part of the Xenopus embryo. We investigated its early role by functional ablation, through mRNA injection of an XHNF1β/engrailed repressor fusion construct (XHNF1β/EngR). Dorsal injections of XHNF1β/EngR mRNA abolish dorsal mesoderm formation, leading to axial deficiencies; ventral injections disrupt ventral mesoderm formation without affecting axial development. XHNF1β/EngR phenotypic effects specifically depend on the DNA-binding activity of its homeodomain and are fully rescued by coinjection of XHNF1β mRNA. Vegetal injection of XHNF1β/EngR mRNA blocks the mesoderm-inducing ability of vegetal explants, Both B-Vg1 and VegT maternal determinants trigger XHNF1β expression in animal caps. XHNF1β/EngR mRNA blocks B-Vg1-mediated, but not by eFGF-mediated, mesoderm induction in animals caps. However, wild-type XHNF1β mRNA does not trigger Xbra expression in animal caps. We conclude that XHNF1β function is essential, though not sufficient, for mesoderm induction in the Xenopus embryo.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
