title: Interlocked feedforward loops control cell-type-specific Rhodopsin expression in the Drosophila eye.
abstract: How complex networks of activators and repressors lead to exquisitely specific cell-type determination during development is poorly understood. In the Drosophila eye, expression patterns of Rhodopsins define at least eight functionally distinct though related subtypes of photoreceptors. Here, we describe a role for the transcription factor gene defective proventriculus (dve) as a critical node in the network regulating Rhodopsin expression. dve is a shared component of two opposing, interlocked feedforward loops (FFLs). Orthodenticle and Dve interact in an incoherent FFL to repress Rhodopsin expression throughout the eye. In R7 and R8 photoreceptors, a coherent FFL relieves repression by Dve while activating Rhodopsin expression. Therefore, this network uses repression to restrict and combinatorial activation to induce cell-type-specific expression. Furthermore, Dve levels are finely tuned to yield cell-type- and region-specific repression or activation outcomes. This interlocked FFL motif may be a general mechanism to control terminal cell-fate specification.
authors.affiliation: Department of Biology, New York University, 100 Washington Square East, New York, NY 10003, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Johnston
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Otake
authors.forename: Pranidhi
authors.initials: P
authors.lastname: Sood
authors.forename: Nina
authors.initials: N
authors.lastname: Vogt
authors.forename: Rudy
authors.initials: R
authors.lastname: Behnia
authors.forename: Daniel
authors.initials: D
authors.lastname: Vasiliauskas
authors.forename: Elizabeth
authors.initials: E
authors.lastname: McDonald
authors.forename: Baotong
authors.initials: B
authors.lastname: Xie
authors.forename: Sebastian
authors.initials: S
authors.lastname: Koenig
authors.forename: Reinhard
authors.initials: R
authors.lastname: Wolf
authors.forename: Tiffany
authors.initials: T
authors.lastname: Cook
authors.forename: Brian
authors.initials: B
authors.lastname: Gebelein
authors.forename: Edo
authors.initials: E
authors.lastname: Kussell
authors.forename: Hideki
authors.initials: H
authors.lastname: Nakagoshi
authors.forename: Claude
authors.initials: C
authors.lastname: Desplan
mesh_terms: D000818:Animals; D004330:Drosophila / Q000166:cytology / Q000196:embryology* / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D005123:Eye / Q000196:embryology; D025461:Feedback, Physiological; D018507:Gene Expression Regulation, Developmental; D053263:Gene Regulatory Networks; D018398:Homeodomain Proteins / Q000378:metabolism; D017956:Photoreceptor Cells, Invertebrate / Q000378:metabolism*; D012243:Rhodopsin / Q000235:genetics*; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D014157:Transcription Factors; C114494:dve protein, Drosophila; C093053:oc protein, Drosophila; C085793:salm protein, Drosophila; D012243:Rhodopsin