JCI Insight (May 2021)

An inducible Cre mouse for studying roles of the RPE in retinal physiology and disease

  • Elliot H. Choi,
  • Susie Suh,
  • David E. Einstein,
  • Henri Leinonen,
  • Zhiqian Dong,
  • Sriganesh Ramachandra Rao,
  • Steven J. Fliesler,
  • Seth Blackshaw,
  • Minzhong Yu,
  • Neal S. Peachey,
  • Krzysztof Palczewski,
  • Philip D. Kiser

Journal volume & issue
Vol. 6, no. 9

Abstract

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The retinal pigment epithelium (RPE) provides vital metabolic support for retinal photoreceptor cells and is an important player in numerous retinal diseases. Gene manipulation in mice using the Cre-LoxP system is an invaluable tool for studying the genetic basis of these retinal diseases. However, existing RPE-targeted Cre mouse lines have critical limitations that restrict their reliability for studies of disease pathogenesis and treatment, including mosaic Cre expression, inducer-independent activity, off-target Cre expression, and intrinsic toxicity. Here, we report the generation and characterization of a knockin mouse line in which a P2A-CreERT2 coding sequence is fused with the native RPE-specific 65 kDa protein (Rpe65) gene for cotranslational expression of CreERT2. Cre+/– mice were able to recombine a stringent Cre reporter allele with more than 99% efficiency and absolute RPE specificity upon tamoxifen induction at both postnatal days (PD) 21 and 50. Tamoxifen-independent Cre activity was negligible at PD64. Moreover, tamoxifen-treated Cre+/– mice displayed no signs of structural or functional retinal pathology up to 4 months of age. Despite weak RPE65 expression from the knockin allele, visual cycle function was normal in Cre+/– mice. These data indicate that Rpe65CreERT2 mice are well suited for studies of gene function and pathophysiology in the RPE.

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