Although Woodford et al. reported that this 4 kb promoter is active in both rods and cones, expression of codon-improved Cre recombinase from the Tg(Rho-icre)1Ck transgene has been shown to be absent from cones and restricted to rods, where it is expressed in the retinal outer nuclear layer. Cre-mediated excision is not detected at 4 days of age, but is detected at 7 days of age, and is maximally active by postnatal day 18 when the level of excision detected equals that detected in adults. In the initial assessment, no abnormality was detected in the retinal morphology or in scotopic or photopic electroretinograms of hemizygotes even at 8 months of age (Li et al., 2005). Because the independently acquired Tg(Rho-icre)1Ck strain used by Sundermeier et al. (PMID: 16908407) was found to also have a contaminating transgene, with bovine RGS9Bp driven by the opsin promoter, genotyping was done to confirm that this strain lacks that contaminating transgene.

This transgene expresses codon-improved Cre recombinase driven by the rhodopsin promoter for localization to the retinal rod cells, primarily in the outer nuclear layer. It is valuable for studies involving localized expression modification in retinal rod cells.

Live mice are available from faculty research colonies. Not available at standard JAX Health status.