Fig. 5. Distribution of gfp transcripts in mesodermal derivatives of embryos carrying different gfp constructs (B-D) in comparison with the expression of the endogenous gene (A). 14-somite stage embryos. (A) deltaD transcripts are visible in the tailbud (black arrowhead), in one to two transverse bands in the presomitic mesoderm (white arrowhead) and in the anterior halves of the somites (black arrows) decreasing in intensity from caudal to rostral. (B) Embryos carrying the 0.5gfp+3' construct reveal strong expression in the tailbud and in the posterior half of the somites from the eighth somite onwards. (C) Embryos carrying the 63.5-0.5gfp construct show gfp transcripts only in newly formed somites. (D) Embryos carrying the 1.3gfp construct also reveal gfp transcription in newly formed somites and in the presomitic mesoderm in a stripe pattern, whereas the tailbud is transcript free.