Fig. 4
Influence of complete absence of bcd on segmentation genes in the embryo. (A-E) bcdCRISPR nc 4 embryo stained for Staufen (A, green), Oskar (B, red), DAPI (C, blue) and merge in (D). (E) high magnification of the posterior end after 3-D reconstitution of the whole stack. Staufen is not localized at the anterior tip due to absence of bcd mRNA (A, stippled green arrow) and appears loosely associated at the posterior end (E, green arrows). (F-J) bcdCRISPR nc 10 embryo stained for Staufen (F, green), Oskar (G, red), DAPI (H, blue) and merge in (I). (J) high magnification of the posterior end after 3-D reconstitution of the whole stack. Staufen is not localized at the anterior tip due to absence of bcd mRNA (F, stippled green arrow). Osk is no longer uniformly localized in the posterior polar plasm (PP) but appears clustered in distinct domains within the PP. (K-O) bcdCRISPR early nc 14 embryo stained for Lgbcd (K, green), Hb (L, red), Cad (M, yellow), DAPI (N, blue) and merge in (O). Hb is not activated due to absence of bcd, and Cad is expressed uniformly along the A-P axis due to lack of repression by bcd. Note the reduced number of blastoderm nuclei, annotated in (N). (P-T) bcdCRISPR late nc 14 embryo stained for Lgbcd (P, green), Hb (Q, red), Cad (R, yellow), DAPI (S, blue) and merge in (T). The late posterior Hb (Q) and Cad (R) bands appear activated at the anterior due to adoption of posterior identities at the anterior. (U-Y) bcdCRISPR late nc 14 embryo stained for Ftz (U, green), Eve (V, red), Cad (W, yellow), DAPI (X, blue) and merge in (Y) as a 3-D reconstruction of the whole stack. Numbers in (U, V and Y) indicate numbering of parasegments (PS) in their respective color of staining. The dashed line in (Y) denotes the mirror plane for the duplication of posterior tissues to the anterior. All embryos are anterior to the left and dorsal side up, unless otherwise noted. Note: due to the mounting procedure, embryos are flattened and may appear somewhat rounder than they actually are