Functional conservation of the wingless-engrailed interaction as shown by a widely applicable baculovirus misexpression system.
BACKGROUND
The expression patterns of the segment polarity genes wingless and engrailed are conserved during segmentation in a variety of arthropods, suggesting that the regulatory interactions between these two genes are also evolutionarily conserved. Hypotheses derived from such comparisons of gene expression patterns are difficult to test experimentally as genetic manipulation is currently possible for only a few model organisms.


RESULTS
We have developed a system, using recombinant baculoviruses, that can be applied to a wide variety of organisms to study the effects of ectopic expression of genes. As a first step, we studied the range and type of infection of several reporter viruses in the embryos of two arthropod and one vertebrate species. Using this system to express wingless, we were able to induce expression of engrailed in the anterior half of each parasegment in embryos of the fruit fly Drosophila melanogaster. Virus-mediated wingless expression also caused ectopic naked ventral cuticle formation in wild-type Drosophila larvae. In the flour beetle, Tribolium castaneum, ectopic wingless also induced engrailed expression. As in Drosophila, this expression was only detectable in the anterior half of the parasegment.


CONCLUSIONS
The functional interaction between wingless and engrailed, and the establishment of cells competent to express engrailed, appears to be conserved between Drosophila and Tribolium. The data on the establishment of an engrailed-competent domain also support the idea that prepatterning by pair-rule genes is conserved between these two insects. The recombinant baculovirus technology reported here may help answer other long-standing comparative evolutionary questions.
Oppenheimer
D I
DI
Department of Organismal Biology, University of Chicago, Chicago, 60637, USA.
MacNicol
A M
AM
Patel
N H
NH
D000818:Animals; D001756:Blastoderm / Q000378:metabolism; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000196:embryology / Q000235:genetics* / Q000254:growth & development; D004625:Embryo, Nonmammalian / Q000378:metabolism / Q000648:ultrastructure; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter; D005822:Genetic Vectors / Q000235:genetics*; D049452:Green Fluorescent Proteins; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics; D018398:Homeodomain Proteins / Q000235:genetics / Q000502:physiology*; D019476:Insect Proteins / Q000235:genetics / Q000502:physiology*; D007814:Larva; D007915:Lepidoptera / Q000166:cytology*; D008164:Luminescent Proteins / Q000096:biosynthesis; D009024:Morphogenesis / Q000235:genetics; D017924:Nucleopolyhedroviruses / Q000235:genetics*; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000502:physiology; D013045:Species Specificity; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*; D014231:Tribolium / Q000196:embryology; D051155:Wnt1 Protein; D014982:Xenopus laevis / Q000196:embryology
D029721:Drosophila Proteins; C063459:En protein, Drosophila; D018840:HSP70 Heat-Shock Proteins; D018398:Homeodomain Proteins; D019476:Insect Proteins; D008164:Luminescent Proteins; D011518:Proto-Oncogene Proteins; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D051155:Wnt1 Protein; C074622:wg protein, Drosophila; D049452:Green Fluorescent Proteins