High impact information on foxh1

• Later signaling mediated by the EGF-CFC protein One-eyed pinhead and the forkhead transcription factor Schmalspur is required to overcome this repression [1].
• We find that sur expression is independent of Nodal signaling and that bon is expressed in the absence of Nodal signaling but requires Nodal signaling and Sur for enhanced, maintained expression [2].
• Here, we analyze whether zebrafish proteins related to FoxH1 [Schmalspur (Sur)] and Mixer [Bonnie and clyde (Bon)] act within or downstream of the Nodal signaling pathway, test whether these two factors have additive or overlapping activities, and determine whether FoxH1/Sur and Mixer/Bon can account for all Nodal signaling during embryogenesis [2].
• Mutants in spadetail or chordino give discordant gene expression among the brain, heart and gut. one-eyed pinhead and schmalspur are necessary for asymmetric gene expression and may mediate signaling from midline domains to lateral tissues [3].
• Our analysis of sur mutants suggests that defects within the posterior prechordal plate may cause aberrant development of ventral CNS structures in the mid- and hindbrain [4].

Biological context of foxh1

• In contrast to the relatively mild defects observed in single mutants, loss of both bon and sur results in a severe phenotype characterized by absence of prechordal plate, cardiac mesoderm, endoderm and ventral neuroectoderm [2].
• Maternal sur transcripts were localized to the animal pole during oogenesis [5].
• The transcription factors Fast-1 and Mixer are important terminal components of Smad2-mediated TGF-beta signal transduction [6].

Anatomical context of foxh1

• In the absence of both maternal and zygotic sur function, embryos failed to form a morphologically distinct gastrula organizer and, later, developed severe defects in all axial structures [5].

Other interactions of foxh1

• In the underlying mesendodermal tissue of the head, sur is needed only for development of the posterior prechordal plate, whereas oep and cyc are required for both anterior and posterior prechordal plate development [4].

References