P element insertion-dependent gene activation in the Drosophila eye.
Insights into the function of a gene can be gained in multiple ways, including loss-of-function phenotype, sequence similarity, expression pattern, and by the consequences of its misexpression. Analysis of the phenotypes produced by expression of a gene at an abnormal time, place, or level may provide clues to a gene's function when other approaches are not illuminating. Here we report that an eye-specific, enhancer-promoter present in the P element expression vector pGMR is able to drive high level expression in the eye of genes near the site of P element insertion. Cell fate determination, differentiation, proliferation, and death are essential for normal eye development. Thus the ability to carry out eye-specific misexpression of a significant fraction of genes in the genome, given the dispensability of the eye for viability and fertility of the adult, should provide a powerful approach for identifying regulators of these processes. To test this idea we carried out two overexpression screens for genes that function to regulate cell death. We screened for insertion-dependent dominant phenotypes in a wild-type background, and for dominant modifiers of a reaper overexpression-induced small eye phenotype. Multiple chromosomal loci were identified, including an insertion 5' to hid, a potent inducer of apoptosis, and insertions 5' to DIAP1, a cell death suppressor. To facilitate the cloning of genes near the P element insertion new misexpression vectors were created. A screen with one of these vectors identified eagle as a suppressor of a rough eye phenotype associated with overexpression of an activated Ras1 gene.
Hay
B A
BA
Department of Molecular and Cell Biology and Howard Hughes Medical Institute, University of California, Berkeley, CA 94720-3200, USA.
Maile
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R
Rubin
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GM
D000818:Animals; D030801:Animals, Genetically Modified; D017209:Apoptosis; D002874:Chromosome Mapping; D017931:DNA Primers; D004251:DNA Transposable Elements; D004330:Drosophila / Q000235:genetics*; D029721:Drosophila Proteins; D004742:Enhancer Elements, Genetic; D005123:Eye / Q000166:cytology* / Q000648:ultrastructure; D018507:Gene Expression Regulation, Developmental; D005799:Genes, Dominant; D017344:Genes, Insect; D016153:Genes, Suppressor; D005819:Genetic Markers; D005838:Genotype; D008855:Microscopy, Electron, Scanning; D009799:Ocular Physiological Phenomena; D009928:Organ Specificity; D010452:Peptide Biosynthesis; D010455:Peptides / Q000235:genetics; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D015533:Transcriptional Activation
D017931:DNA Primers; D004251:DNA Transposable Elements; D029721:Drosophila Proteins; D005819:Genetic Markers; D010455:Peptides; D011993:Recombinant Fusion Proteins; C086973:rpr protein, Drosophila