Transgenic mice expressing a functional human photopigment

Area of Science:

• Vision science
• Genetics
• Molecular biology

Background:

• Retinal photopigments are crucial for visual system evolution, with changes altering visual perception.
• Introducing novel photopigments can expand visual capacities.

Purpose of the Study:

• To determine if a human cone photopigment gene, when introduced into the mouse genome, would be expressed specifically in cones.
• To assess if the human photopigment would support functional phototransduction in mice.

Main Methods:

• Generated transgenic mice carrying the human long-wavelength-sensitive (L) photopigment gene.
• Analyzed gene expression using reverse transcription-polymerase chain reaction (RT-PCR).
• Localized photopigment protein via antibody staining and assessed light transduction using electroretinography (ERG).

Main Results:

• The human L photopigment gene was specifically expressed in mouse cones at levels comparable to mouse middle-wavelength-sensitive (M) pigment gene.
• Immunocytochemistry confirmed abundant synthesis and translocation of human L pigment to outer segments without cone degeneration.
• ERG spectral sensitivity analysis demonstrated the human L pigment efficiently elicited electrical responses.

Conclusions:

• The human L photopigment effectively transduces light in mouse cones, suggesting conserved protein domains for transport and signaling.
• The broad expression in mouse cones indicates potential lack of specific regulatory elements or recognition issues in mouse UV-sensitive cones.