Figure 1
From: Cap’n’collar differentiates the mandible from the maxilla in the beetle Tribolium castaneum
Expression of Tc-Dfd and Tc-cnc in the mandibular and maxillary segments. All views are ventral with anterior to the left unless otherwise indicated. Gene expression was determined by in situ hybridization. (A) Expression of Tc-cnc in a germ band extending stage embryo. There is an anterior cap domain of Tc-cnc in the labrum (arrowhead). The posterior collar domain is present in the mandibular segment (arrow). (B) Tc-Dfd expression in a germ band extending embryo as limb buds are just about to form. Expression is present throughout the mandibular and maxillary segments. (C-J) Expression of Tc-Dfd (blue) and Tc-cnc (red) in wild-type embryos. Coexpression of Tc-Dfd and Tc-cnc is brown. (C) Early germ band extending embryo. (D) Germ band extending stage embryo prior to limb bud formation. (E) Germ band extending embryo. (F) Late germ band extending embryo. (G) Same embryo as (F), but a lower plane of focus that shows the reduction of Tc-cnc expression in the mesoderm (asterisk). (H) Germ band retracting embryo. (I) Embryo undergoing dorsal closure with the gnathal appendages moving towards the ventral midline. (J) Same embryo as (I), but a lower plane of focus that shows the reduction of Tc-cnc expression in the mesoderm (asterisk). (C,D) Prior to limb bud formation, Tc-Dfd expression is continuous throughout the mandibular segment. (E,F) As soon as the endites start to form, Tc-Dfd expression retracts from the developing mandibular endites (star) whilst Tc-cnc expression is maintained throughout the mandibular appendage. (G-J) By late embryogenesis, faint Tc-Dfd expression is only present in the lateral part of the mandibular limb bud (arrow), and missing from the ventral-medial region (star). Tc-Dfd expression is still strongly maintained in the maxillary limb bud. Mandibular (Mn), maxillary (Mx) and labial (La) segments.