Figure 2
Expression of Glomeris even-skipped and runt. Expression of even-skipped (A-D, M) and runt (E-L, N). (A'-D') show DAPI counter-staining of the embryos shown in (A-D). (A) Stage 1 embryo. Segmental stripes in every segment. Bracket marks premandibular and mandibular segments. Asterisk marks stripe of expression in the SAZ. (B) Stage 1.1 embryo. Arrow points to fading ventral expression. Note that the expression in the SAZ in (A) (asterisk) is now in the nascent segment anterior to the SAZ (asterisk in (B)) and a new expression domain is forming in the SAZ (filled circle). (C) Stage 1.2 embryo. Arrow points to expression in the CNS. Note that the expression domain seen in the SAZ in (B) has developed into a single broad domain (filled circle). (D) Stage 2 embryo. Former expression in the SAZ has transformed into a stripe in the nascent segment (filled circle). A new expression domain forms in the SAZ (open circle). (A'-D') DAPI counter-staining of the embryos shown in (A-D). (E) Stage 0.4 embryo. Bracket marks premandibular and antennal segments. Expression in the SAZ (asterisk). (F) Stage 1 embryo. Arrow points to disappearing ventral expression. Expression seen in the SAZ in A now lies in the nascent segment anterior to the SAZ (asterisk). A new domain of expression has formed in the SAZ (filled circle). Bracket as in (E). (G) Stage 1.2 embryo. Arrow points to expression in the CNS. Expression in the SAZ seen in (F) is now in the nascent segment anterior to the SAZ (filled circle). Expression seen in the SAZ in (E) (asterisk) is now one segment anterior to it. A new domain appears in the SAZ (open circle). (H) Stage 2 embryo. Arrow as in (G). Expression in the SAZ (open circle) expands. Arrowhead points to strengthened expression in the postmaxillary segment. (I-L) Dynamic expression of runt in the SAZ in four consecutive developmental stages (that is, stage 3.1 to 3.4). (M, N) Concentric expression of even-skipped (M) and runt (N) around the proctodaeum. In all pictures anterior is to the left. Abbreviations: an, antennae; ic, intercalary (premandibular) segment; md, mandibular segment; oc, ocular field; P, proctodaeum; SAZ, segment addition zone; T, trunk segment.