Appendix 1—figure 2. Expression of slp at phase 2 versus phase 3.

Relative expression of slp and other pair-rule genes (A, B – eve; C, D – runt; E, F – ftz; G, H - odd) is shown in late phase 2 embryos (A, C, E, G) and in early phase 3 embryos (B, D, F, H). Individual channels are shown to the right of each whole embryo double channel image (slp bottom, other gene top). Other panels show blow-ups of expression in stripes 2–6 (individual channels, double channel image, and thresholded double channel image). slp expression is always shown in green. slp expression overlaps with runt at phase 3 (D) but not at phase 2 (C). slp expression overlaps with ftz and odd at phase 2 (E, G) but not phase 3 (F, H). slp expression never overlaps with eve (A, B). Arrowheads in (D) indicate cells where slp secondary stripe expression does not coincide with runt expression. Scale bars = 50 μm. See text for details.

DOI: http://dx.doi.org/10.7554/eLife.18215.025

Appendix 1—figure 2—figure supplement 1. Model for the regulation of slp transcription at phase 2 versus phase 3.

Model for the differential regulation of slp expression by pair-rule proteins at late phase 2 (A, B) versus mid phase 3 (C, D). (A, C) Schematic diagrams showing the expression of slp relative to potential regulators. The horizontal axis represents an idealised portion of the AP axis (~12 nuclei across). The grey vertical lines demarcate a double parasegment repeat (~8 nuclei across). (B, D) Inferred regulatory interactions. Hammerhead arrows represent repressive interactions. Solid black arrows represent interactions that are currently in operation; dashed grey arrows represent those that are not. At each stage, slp is expressed only where its current repressors are absent. See Appendix 1—figure 2 for staged relative expression data. Note that the expression patterns of potential regulators diagrammed in this figure represent protein distributions, which often differ slightly from transcript distributions due to time delays inherent in protein synthesis and decay (see Figure 6).

DOI: http://dx.doi.org/10.7554/eLife.18215.026

Appendix 1—figure 2—figure supplement 2. Runt represses slp during phase 2 in both wild-type and ftz mutant embryos.

Relative expression of runt and slp in wild-type and ftz mutant embryos. In both cases, co-expression of runt and slp is not seen until phase 3. Individual channels are shown to the right of each double-channel image. All panels show a lateral view, anterior left, dorsal top.

DOI: http://dx.doi.org/10.7554/eLife.18215.027