Fig. 3.

Hox genes can activate m5-5-driven lacZ expression in a chick co-electroporation assay. (A-F′) Co-expression of mouse (m) Hoxa4, Hoxa5, Hoxb4, Hoxb5, Hoxc4 and Hoxc5 pCIG expression plasmids (identified by expression of GFP, green in A-F) with the m5-5 BGZA reporter vector in chick hindbrain results in activation of the lacZ reporter gene (A′-F′, blue). (G) The number of β-galactosidase-positive embryos among the total number of GFP-positive embryos as a reflection of lacZ activation. This activation does not occur with the expression plasmid alone (pCIG) and is homeodomain dependent (Hoxc5 delHD). o.v., otic vesicle.