Direct control of the proneural gene atonal by retinal determination factors during Drosophila eye development.
The determination of neuronal identity in Drosophila cells depends on the accurate expression of proneural genes. The proneural gene atonal (ato) encodes a basic-HLH protein required for photoreceptor and chordotonal organ formation. The initial expression of ato in imaginal discs is regulated by sequences that lie 3' to its open reading frame. In this report, we show that the initial ato transcription in different imaginal discs is regulated by distinct 3' cis-regulatory sequences. The eye-specific ato 3' cis-regulatory sequence consists of two distinct elements we term 2.8 PB and 3.6 BP that regulate ato transcription during different stages of eye development. The 2.8 PB enhancer contains a highly conserved consensus binding site for the retinal determination (RD) factor Sine oculis (So). Mutation of this So binding site abolishes 2.8 PB enhancer activity. Furthermore the RD factors So and Eyes absent (Eya) are required for 2.8 PB enhancer activity and can induce ectopic 2.8 PB reporter expression. In contrast, ectopic Dpp signaling is not sufficient to induce ato 3' enhancer activation but can induce increased levels of RD factor Dachshund (Dac) and synergize with So and Eya to increase ato 3' enhancer activity. These results demonstrate a direct mechanism by which the RD factors regulate ato expression and suggest an important role of Dpp in the activation of ato 3' enhancer is to regulate the levels of RD factors.
Tanaka-Matakatsu
Miho
M
Ben May Department for Cancer Research, The University of Chicago, 929 E. 57th Street, Chicago, IL 60637, USA.
Du
Wei
W
D000818:Animals; D030801:Animals, Genetically Modified; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D004330:Drosophila / Q000196:embryology / Q000235:genetics*; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004625:Embryo, Nonmammalian; D004742:Enhancer Elements, Genetic; D005123:Eye / Q000196:embryology*; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D018507:Gene Expression Regulation, Developmental; D017344:Genes, Insect; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D007150:Immunohistochemistry; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D038081:Organogenesis; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D050436:Regulatory Elements, Transcriptional; D012160:Retina / Q000196:embryology / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D014158:Transcription, Genetic
D051792:Basic Helix-Loop-Helix Proteins; D029721:Drosophila Proteins; D005136:Eye Proteins; D049452:Green Fluorescent Proteins; D018398:Homeodomain Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; C087345:So protein, Drosophila; C082142:ato protein, Drosophila; C103968:dac protein, Drosophila; C064196:dpp protein, Drosophila; C092694:eya protein, Drosophila