Mouse Mix gene is activated early during differentiation of ES and F9 stem cells and induces endoderm in frog embryos.

In frog and zebrafish, the Mix/Bix family of paired type homeodomain proteins play key roles in specification and differentiation of mesendoderm. However, in mouse, only a single Mix gene (mMix) has been identified to date and its function is unknown. We have analyzed the expression of mouse Mix RNA and protein in embryos, embryoid bodies formed from embryonic stem cells and F9 teratocarcinoma cells, as well as several differentiated cell types.

Structure, upstream promoter region, and functional domains of a mouse and human Mix paired-like homeobox gene.

Mix/Bix proteins represent a vertebrate subgroup of paired-like homeodomain proteins which are known to function around the time of gastrulation. Here we report the structures of the genomic and upstream promoter regions of a mouse and human Mix-like gene. Both genes map to syntenic regions of chromosome 1 and contain two coding exons, with the paired-type homeodomain split between the exons within helix 3.