Fig. 1

Expression of the Bf-Gsx-Up-Proximal construct in Ciona intestinalis. a Genomic map of the region comprising the Bf-Gsx-Up-Proximal regulatory element, with pCES LacZ reporter schematic. b-d LacZ expression is observed from the earliest collected stages in neural plate cells. e-m Tailbud stages: expression can be observed in the mid-posterior of the sensory vesicle, the visceral ganglion and in every cell of the tail nerve cord. Only the very anterior tip of the sensory vesicle does not express LacZ. j ltb embryo with expression only in the sensory vesicle. m Anterior region of a Ciona larva displaying strong expression in all four rows (dorsal, ventral, left and right) of the tail nerve cord. All embryos and larvae are lateral views (except B and M, which are dorsal views) with anterior to left. Square brackets in (l-m) indicate the extent of the sensory vesicle. Lower case lettering refers to the stage of development; g, gastrula; n, neurula; itb, initial tailbud; etb, early tailbud; mtb, mid tailbud; ltb, late tailbud. Scale bars represent 100 μm