Mix.1, a homeobox mRNA inducible by mesoderm inducers, is expressed mostly in the presumptive endodermal cells of Xenopus embryos

Molecular components of the endoderm specification pathway in Xenopus tropicalis

“…In total, we identified one tMixer EST, eight nearly identical tMix ESTs, and six nearly identical tBix ESTs, all of which correspond to full-length cDNAs (Table 1). In contrast, the pseudotetraploid laevis has a more complex set of genes, with one Mixer (Henry and Melton, 1998), two Mix genes (Rosa, 1989;Vize, 1996), and four Bix genes (Tada et al, 1998;Ecochard et al, 1998). The slight variation in the EST sequences within the tMix and tBix clusters (on average 98% identical) was in some cases due to sequencing errors.…”

“…VegT activity results in the transcription of zygotic endodermal genes (Zhang et al, 1998;Clements et al, 1999;Xanthos et al, 2001), which include the following: nodalrelated proteins (Xnr1,2,4,5,6) and derriere, which are members of the transforming growth factor-beta (TGF␤) growth factor family (Jones et al, 1995;Joseph and Melton, 1997;Sun et al, 1999;Takahashi et al, 2000); homeodomain proteins of the Mixer/Mix/Bix family (Rosa, 1989;Vize, 1996;Henry and Melton, 1998;Tada et al, 1998;Casey et al, 1999); the zinc finger factors Gata 4, 5, and 6 (Jiang and Evans, 1996;Weber et al, 2000;Xanthos et al, 2001); and two closely related HMG domain transcription factors, Sox17␣ and Sox17␤ (Husdon et al, 1997).…”

Control of gastrula cell motility by the Goosecoid/Mix.1/ Siamois network: Basic patterns and paradoxical effects

“…These factors can bind to similar DNA sites individually and as homo-or heterodimers (Wilson et al, 1993), and competition for binding sites and combinatorial physical interactions potentially generate complex regulation networks. An established interaction partner for Gsc is Mix.1 (Rosa, 1989). Gsc dimerizes with Mix.1 in vitro (Wilson et al, 1993), and acts together with Mix.1 as transcriptional repressor (Wacker et al, 1998 (Rosa, 1989;Vize, 1996;Tada et al, 1998;Mead et al, 1998;Henry and Melton, 1998;Ecochard et al, 1998;Saka et al, 2000; for a review, see Wardle and Smith, 2006).…”

“…An established interaction partner for Gsc is Mix.1 (Rosa, 1989). Gsc dimerizes with Mix.1 in vitro (Wilson et al, 1993), and acts together with Mix.1 as transcriptional repressor (Wacker et al, 1998 (Rosa, 1989;Vize, 1996;Tada et al, 1998;Mead et al, 1998;Henry and Melton, 1998;Ecochard et al, 1998;Saka et al, 2000; for a review, see Wardle and Smith, 2006). For some of these, ectopic expression is sufficient to induce endoderm formation, but the almost identical Mix.1 and Mix.2 have to synergize with other family members to perform this function (Mead et al, 1998;Henry and Melton, 1998;Lemaire et al, 1998).…”

Molecular and developmental biology of the hemangioblast

“…One of major nodal/activin and BMP4 targets includes Mix/Bix homeobox genes in the Xenopus laevis gastrula embryos (Rosa, 1989;Mead et al, 1996;Vize, 1996;Henry and Melton, 1998). The single mouse Mix gene, Mixl1, is expressed in the visceral endoderm of pregastrulation embryo, the primitive streak in the gastrula, and the posterior primitive streak and allantois at 8.5 dpc (Pearce and Evans, 1999;Robb et al, 2000).…”