title: An in vivo doxycycline-controlled expression system for functional studies of the retina.
abstract: OBJECTIVE
  Transgenic mice were developed that express tetracycline-controlled transactivator 1 (tTA1) specifically in photoreceptor cells. In these mice the transcription of the gene of interest can be easily inactivated in the retina in a short time frame.
  
  
  METHODS
  A construct was prepared containing tTA1 under control of the murine rhodopsin regulatory region. This construct was used for the generation of transgenic mice. In situ hybridization was performed to study the distribution of the transactivator in the retina. The activity of the transactivator was analyzed by mating the lines with a luciferase reporter transgenic mouse. tTA1 activity and doxycycline's ability to block it were analyzed by luciferase assay. The effects of tTA1 on the retina were assessed by histology and electrophysiology.
  
  
  RESULTS
  Two transgenic lines were developed that specifically express tTA1 in photoreceptor cells. The time course of transgene expression replicated transcription of endogenous rhodopsin. tTA1 was not toxic to the retina. Transactivator activity was blocked readily by doxycycline.
  
  
  CONCLUSIONS
  An expression system for photoreceptor cells was generated to drive transcription in a cell-specific and time-controllable manner. This system is suitable for the study of factors involved in retinal biology and of mutant forms of genes involved in retinal diseases.
authors.affiliation: Telethon Institute of Genetics and Medicine, Naples, Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Angeletti
authors.forename: Jana
authors.initials: J
authors.lastname: Löster
authors.forename: Alberto
authors.initials: A
authors.lastname: Auricchio
authors.forename: Florian
authors.initials: F
authors.lastname: Gekeler
authors.forename: Kei
authors.initials: K
authors.lastname: Shinoda
authors.forename: Andrea
authors.initials: A
authors.lastname: Ballabio
authors.forename: Jochen
authors.initials: J
authors.lastname: Graw
authors.forename: Valeria
authors.initials: V
authors.lastname: Marigo
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D004318:Doxycycline / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects*; D017403:In Situ Hybridization; D007763:Lac Operon / Q000235:genetics; D051379:Mice; D008822:Mice, Transgenic; D020419:Photoreceptor Cells, Vertebrate / Q000502:physiology*; D012243:Rhodopsin / Q000235:genetics; D017299:Rod Opsins / Q000096:biosynthesis; D015534:Trans-Activators; D015533:Transcriptional Activation / Q000187:drug effects; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D017299:Rod Opsins; D015534:Trans-Activators; D012243:Rhodopsin; D001616:beta-Galactosidase; D004318:Doxycycline