High impact information on sox32

• In the absence of cas activity, endoderm progenitors differentiate into mesodermal derivatives [1].
• Initial cas expression appears in the dorsal yolk syncytial layer (YSL) in the early blastula, and is independent of Nodal signaling [2].
• casanova (cas) mutant zebrafish embryos lack endoderm and develop cardia bifida [1].
• The cas phenotype is rescued by overexpression of 10J3 and can be mimicked by 10J3-directed morpholinos [1].
• Further, MZspg mutants do not maintain expression of sox32/casanova, express little or no sox17, and fail to develop endodermal tissue [3].

Biological context of sox32

• We show that Eomes is required for endogenous endoderm induction, acting via an essential binding site in the cas promoter [4].
• Altogether, these results suggest that Fgf signaling negatively regulates endoderm induction, possibly through repression of cas expression and down-regulation of Cas function [5].

Anatomical context of sox32

• The joint control of endoderm formation by spg and cas suggests that the endodermal germlayer may be a tissue unit with distinct genetic control, thus adding genetic support to the germlayer concept in metazoan development [6].
• We further demonstrate that overexpression of 226D7 increases the number of sox17-expressing endodermal progenitor cells without upregulating the expression of the Nodal genes, cyclops and squint [7].
• Eomes synergizes potently with Bon and Gata5 to induce cas, even in animal pole blastomeres [4].

Other interactions of sox32

• Alterations of dorsoventral Bmp signalling do not perturb the induction of endodermal precursors, as shown by normal amounts of cells expressing cas and sox17 in swirl and chordino gastrulae, but affect dramatically the expression pattern of her5, a regulator of endoderm anteroposterior patterning in zebrafish [8].
• Here, we show that cas expression depends upon the T box transcription factor Eomesodermin (Eomes), a maternal determinant that is localized to marginal blastomeres [4].

Analytical, diagnostic and therapeutic context of sox32

• Cell transplantations show that spg acts in early endodermal precursors, and cas mRNA-injection into MZspg embryos does not restore endoderm development. spg and cas together are both necessary and sufficient to activate endoderm development, and stimulate expression of a sox17 promoter-luciferase reporter [6].
• 226D7 was isolated by an in situ hybridization screening for genes expressed in the yolk syncytial layer (YSL) at the blastula stage [7].

References