Expression of Hox genes in <i>corto</i> mutant embryos.

<p>A. Anti-Ubx antibody staining of <i>w¹¹¹⁸</i> embryos, or embryos depleted of maternal and zygotic Corto. Upper row, lateral view and lower row, dorsal view. (B) Dorsal view. In wild-type embryos (left), <i>Ubx</i> is expressed from parasegment PS5 to PS12 with a higher expression in PS6. In <i>corto</i> embryos (right), the anterior boundary of <i>Ubx</i> is not modified but <i>Ubx</i> is strongly downregulated in PS11 and PS12 (arrowheads) . Parasegment numbers are indicated in white and the anterior border of <i>Ubx</i> expression by arrows. B. Anti-AbdB antibody staining of <i>w¹¹¹⁸</i> embryos, or embryos depleted of maternal and zygotic Corto. Upper row, close-ups of the ventral nerve chord. In wild-type embryos (left), <i>Abd-B</i> is expressed in a decreasing gradient from PS13 to PS10. In <i>corto</i> embryos (right), this gradient extends anteriorly to PS9 and PS8. Moreover, expression of <i>Abd-B</i> seems to be higher in PS13 to PS10. Lower row, dorsal view of whole mount embryos showing ectodermal <i>Abd-B</i> expression; note ectopic expression of <i>Abd-B</i> in anterior parasegments in <i>corto</i> mutant embryos (arrows).