title: Probing the Drosophila retinal determination gene network in Tribolium (II): The Pax6 genes eyeless and twin of eyeless.
abstract: The Pax6 genes eyeless (ey) and twin of eyeless (toy) are upstream regulators in the retinal determination gene network (RDGN), which instructs the formation of the adult eye primordium in Drosophila. Most animals possess a singleton Pax6 ortholog, but the dependence of eye development on Pax6 is widely conserved. A rare exception is given by the larval eyes of Drosophila, which develop independently of ey and toy. To obtain insight into the origin of differential larval and adult eye regulation, we studied the function of toy and ey in the red flour beetle Tribolium castaneum. We find that single and combinatorial knockdown of toy and ey affect larval eye development strongly but adult eye development only mildly in this primitive hemimetabolous species. Compound eye-loss, however, was provoked when ey and toy were RNAi-silenced in combination with the early retinal gene dachshund (dac). We propose that these data reflect a role of Pax6 during regional specification in the developing head and that the subsequent maintenance and growth of the adult eye primordium is regulated partly by redundant and partly by specific functions of toy, ey and dac in Tribolium. The results from embryonic knockdown and comparative protein sequence analysis lead us further to conclude that Tribolium represents an ancestral state of redundant control by ey and toy.
authors.affiliation: Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Detroit, MI 48202, USA.
authors.forename: Xiaoyun
authors.initials: X
authors.lastname: Yang
authors.forename: Markus
authors.initials: M
authors.lastname: Weber
authors.forename: Nazanin
authors.initials: N
authors.lastname: Zarinkamar
authors.forename: Nico
authors.initials: N
authors.lastname: Posnien
authors.forename: Frank
authors.initials: F
authors.lastname: Friedrich
authors.forename: Barbara
authors.initials: B
authors.lastname: Wigand
authors.forename: Rolf
authors.initials: R
authors.lastname: Beutel
authors.forename: Wim G M
authors.initials: WG
authors.lastname: Damen
authors.forename: Gregor
authors.initials: G
authors.lastname: Bucher
authors.forename: Martin
authors.initials: M
authors.lastname: Klingler
authors.forename: Markus
authors.initials: M
authors.lastname: Friedrich
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D054910:Compound Eye, Arthropod / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D017124:Conserved Sequence; D004268:DNA-Binding Proteins / Q000235:genetics; D004330:Drosophila / Q000235:genetics*; D029721:Drosophila Proteins / Q000235:genetics; D005136:Eye Proteins / Q000235:genetics*; D055785:Gene Knockdown Techniques; D053263:Gene Regulatory Networks; D018398:Homeodomain Proteins / Q000235:genetics*; D019476:Insect Proteins / Q000096:biosynthesis* / Q000235:genetics; D008969:Molecular Sequence Data; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors / Q000235:genetics*; D012097:Repressor Proteins / Q000235:genetics*; D015534:Trans-Activators / Q000235:genetics; D014231:Tribolium / Q000196:embryology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D005136:Eye Proteins; D018398:Homeodomain Proteins; D019476:Insect Proteins; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D012097:Repressor Proteins; D015534:Trans-Activators; C113278:ey protein, Drosophila; C118464:toy protein, Drosophila