In the blind subterranean mole rat Spalax ehrenbergi superspecies complete ablation of the visual imageforming capability has been accompanied by an expansion of the bilateral projection from the retina to the suprachiasmatic nucleus. We have cloned the open reading frame of a visual pigment from Spalax that shows >90% homology with mammalian rod pigments. Baculovirus expression yields a membrane protein with all functional characteristics of a rod visual pigment (λmax) = 497 ± 2 nm; pKa of meta I/meta II equilibrium = 6.5; rapid activation of transducin in the light). We not only provide evidence that this Spalax rod pigment is fully functional in vitro but also show that all requirements for a functional pigment are present in vivo. The physiological consequences of this unexpected finding are discussed. One attractive option is that during adaptation to a subterranean lifestyle, the visual system of this mammal has undergone mosaic reorganization, and the visual pigments have adapted to a function in circadian photoreception.
|Number of pages||6|
|Journal||Journal of Biological Chemistry|
|State||Published - 8 Dec 2000|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology