Fig. 7. Effect of reduction of her1 function on segmentation and cyclic gene expression. The myotome boundaries of the trunk marked by twitchin expression are shown in 26 hpf embryos in lateral view, anterior towards the left and dorsal upwards (B,C). The expression of segmental and cyclic genes in the presomitic mesoderm and trunk somites of embryos at 14 hpf (10 somites) are shown in dorsal view after flat mounting with anterior up (D-K). Arrows and arrowheads indicate localized defects and brackets indicate the extent of larger regions of abnormalities. Scale bar in B: 250 µm for A,B. Embryos prior to somitic furrow formation at 10 hpf (bud stage) are shown in lateral view (L,M) and in dorsal view after flat mounting (N). Arrows indicate the anterior-most expression of genes in the PSM, arrowheads show the location of the yolk plug (vegetal). Scale bar in N: 100 µm. (A) Diagram of the position of the her1m1 morpholino with respect to the translation start site (+1, ATG) of the her1 mRNA. (B) Uninjected wild-type control. (C) Wild type injected with 5 ng/µl her1m1. Expression of myod (D,E), dlc (F,G), her1 (H,I) and her7 (J,K) in uninjected embryos (D,F,H,J) and in embryos injected with 5 ng/µl her1m1 (E,G,I,K). Expression of mespa (L) and her1 (M) and co-expression of mespa (blue) and her1 (red) prior to somite formation (N).