title: A test for cell autonomy, based on di-cistronic messenger translation.
abstract: We have devised a test for cell autonomy of a gene that is switched on ectopically in a clone of cells, allowing us to ask whether the wild-type activity of this gene can influence neighbouring cells. To switch on the test gene, we used the yeast FRT system, and marked the FRT-generated cell clone by co-expressing beta-galactosidase. Co-expression is achieved by a stretch of 5' untranslated mRNA from the homeotic gene Ultrabithorax (Ubx), which is inserted between the two coding sequences. We show that this Ubx sequence mediates efficient and reliable di-cistronic mRNA translation in wing imaginal discs of Drosophila. Applying our test to Ubx, we find that ectopic Ubx in wing discs strictly coincides with beta-galactosidase expression. Consequently, wing cells are transformed into cells that appear to be intermediates between wing and haltere cells, contesting the view that homeotic genes act as binary switches.
authors.affiliation: MRC Laboratory of Molecular Biology, Cambridge, UK.
authors.forename: K
authors.initials: K
authors.lastname: Hart
authors.forename: M
authors.initials: M
authors.lastname: Bienz
mesh_terms: D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics*; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000196:embryology*; D004627:Embryonic Induction; D018507:Gene Expression Regulation, Developmental; D005801:Genes, Homeobox; D018398:Homeodomain Proteins / Q000235:genetics*; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics; D014157:Transcription Factors; D014921:Wings, Animal / Q000196:embryology
chemical_list: D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; C066177:Ubx protein, Drosophila