An in vivo doxycycline-controlled expression system for functional studies of the retina.
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.
Angeletti
Barbara
B
Telethon Institute of Genetics and Medicine, Naples, Italy.
Löster
Jana
J
Auricchio
Alberto
A
Gekeler
Florian
F
Shinoda
Kei
K
Ballabio
Andrea
A
Graw
Jochen
J
Marigo
Valeria
V
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
D000900:Anti-Bacterial Agents; D017299:Rod Opsins; D015534:Trans-Activators; D012243:Rhodopsin; D001616:beta-Galactosidase; D004318:Doxycycline