Figure 9
From: Cap’n’collar differentiates the mandible from the maxilla in the beetle Tribolium castaneum
A model of Tc-cnc and Tc-Dfd mandibular and maxillary patterning functions in Tribolium castaneum. Tc-Dfd patterns both the mandible and maxillary segments. Tc-Dfd patterns the protopodites of these appendages. Note that the anterior ‘cap’ domain of Tc-cnc has been omitted from this scheme for clarity. Tc-Dfd expression is shown in blue, Tc-cnc expression is shown in red. Tc-cnc and Tc-Dfd expression is shown in purple. (A) Tc-Dfd is expressed in the mandibular and maxillary segments and patterns these segments. In the mandibular segment, Tc-Dfd represses antennal development. Tc-Dfd patterns the maxillary segment in conjunction with Tc-mxp. (B) Tc-Dfd activates Tc-cnc expression and together Tc-cnc and Tc-Dfd cooperate to pattern the mandibular segment. (C) Tc-Dfd patterns the protopodite of the mandibular and maxillary appendages in germ band extending embryos, but is repressed from the mandibular limb bud as it develops. (D) In germ band retracting stage embryos, Tc-cnc has differentiated the mandibular appendage from maxillary identity.