Developmental onsets of activity of notochord CRMs representative of the multiple- and single-site Ci-Bra targets, and of two notochord CRMs lacking Ci-Bra binding sites.

<p>Time-course experiments were carried out by WMISH on transgenic embryos (A–F) carrying the notochord CRMs indicated on the top right corner of (A, C, E), fixed at the 110-cell (A,C,E) and early gastrula stage (B,D,F). Insets in the bottom right corners display high-magnification views of representative stained embryos. The inset in the top right corner of (F) shows an embryo carrying the −0.6 kb <i>Ci-Noto1>LacZ</i> transgene stained with X-Gal. (G) Graph of a representative time-course experiment, reporting the number of transgenic embryos showing <i>LacZ</i> expression in notochord precursors, for the constructs and stages detailed in the panel. <i>n</i>, number of scored embryos showing hybridization signal. (H) Graph of time-course experiments for the notochord CRMs associated with the late-onset genes <i>Ci-ACL</i> and <i>Ci-β4GalT</i>, as determined by X-Gal staining. Results of three representative experiments were averaged. The number of embryos scored for the <i>Ci-ACL</i> CRM was: neural plate, <i>n</i> = 327; neurula, <i>n</i> = 419; initial tailbud, <i>n</i> = 389; early tailbud, <i>n</i> = 237. The number of embryos scored for the <i>Ci-β4GalT</i> CRM was: neural plate, <i>n</i> = 342; neurula, <i>n</i> = 402; initial tailbud, <i>n</i> = 348; early tailbud, <i>n</i> = 220.