Characterization of gene recombination pattern induced by Tg(Crx-cre)1Tfur mouse strain in visual system organs

Retinas are more and more considered in research, as a part of the Central Nervous System (CNS) sharing the same embryonic origin as brain, and thus displays similarities to it on many aspects. Thus, deciphering retinal processes may bring information on downstream central structures of the CNS in addition to understanding retina by itself. Therefore, access to suitable in vivo tools to create appropriate models to decipher retina-specific phenomena and their impacts on other tissues became a need. Some years ago, the new murine strain Tg(Crx-cre)1Tfur was published as a tool to induce retina-specific gene recombination, and literature reported its efficiency to induce a global gene recombination in all retinal layers and cell types at post-natal ages. However, to our knowledge, no study of the retina-specificity of Tg(Crx-Cre)-induced recombination had been published yet. Here we aimed to further investigate the gene-recombination pattern induced by Tg(Crx-Cre) among the structures of the visual system, to bring clear clues of the fair use that could be done of the Tg(Crx-Cre) murine strain. Our results showed that Tg(Crx-Cre) induced a total gene recombination in retinas but also scattered significantly brain structures. Therefore we advise that Tg(Crx-cre)1Tfur must be used in studies focusing strictly on retina and conclusions should be carefully drawn taking into account the non-retina-specificity of gene recombination.