An in vivo XXXX -controlled expression system for functional studies of the retina.

@entity1999 @entity19 @entity3403 @entity989 @entity803
PURPOSE: @entity19 were developed that express @entity803 -controlled transactivator 1 (tTA1) specifically in photoreceptor cells. In these @entity19 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 @entity19 @entity1999 regulatory region. This construct was used for the generation of @entity19 . 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 @entity19 . tTA1 activity and @entity3403 '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 @entity1999 . tTA1 was not toxic to the retina. Transactivator activity was blocked readily by @entity3403 . 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 @entity989 .
