RPE-specific mice suitable for gene activation and inactivation

A tetracycline-inducible Cre mouse line created specifically to study the retinal pigment epithelium (RPE) is suitable for Cre/lox-based gene activation and inactivation in adult RPE, which makes the mice suitable for long-term studies requiring conditional gene targeting.

According to researchers in the Department of Ophthalmology, the Second Affiliated Hospital of Nanchang University, Nanchang, China, and the University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA, intravitreal Dox delivery can effectively induce productive Cre-mediated recombination in this mouse line, with no apparent Dox or Cre toxicity. The mice have been used for several conditional gene-targeting studies.

The researchers conducted an analysis of Cre expression and function in double transgenic mice that were derived from inducible RPE-specific Cre and Cre-activatable ROSA26 lacZ reporter mice. Cre expression was induced by intravitreal doxycycline. The researchers used reverse transcription–polymerase chain reaction (RT-PCR), immunoblotting, immunostaining and in situ enzymatic assay for β-galactosidase to examine Cre expression and function, and electroretinography and morphometry to examine retinal integrity. They found that Cre expression was significantly elevated by the intravitreal doxycycline injection, resulting in productive Cre-mediated recombination in about 60% of the RPE cells in these mice, with no effect on the integrity of the retina.

"Our work provides a way for more effective use of this mouse line," the researchers wrote. "However, other approaches capable of increasing the efficiency of productive Cre-mediated recombination may permit equal or better utilization of this mouse line. The end-users should explore these avenues that fit their individual experimental goals."

To read the entire study visit the journal Molecular Vision.