The primordial, blue-cone color system of the mouse retina

J Neurosci. 2005 Jun 1;25(22):5438-45. doi: 10.1523/JNEUROSCI.1117-05.2005.


Humans and old world primates have trichromatic color vision based on three spectral types of cone [long-wavelength (L-), middle-wavelength (M-), and short-wavelength (S-) cones]. All other placental mammals are dichromats, and their color vision depends on the comparison of L- and S-cone signals; however, their cone-selective retinal circuitry is still unknown. Here, we identified the S-cone-selective (blue cone) bipolar cells of the mouse retina. They were labeled in a transgenic mouse expressing Clomeleon, a chloride-sensitive fluorescent protein, under the control of the thy1 promoter. Blue-cone bipolar cells comprise only 1-2% of the bipolar cell population, and their dendrites selectively contact S-opsin-expressing cones. In the dorsal half of the mouse retina, only 3-5% of the cones express S-opsin, and they are all contacted by blue-cone bipolar cells, whereas all L-opsin-expressing cones (approximately 95%) are avoided. In the ventral mouse retina, the great majority of cones express both S- and L-opsin. They are not contacted by blue-cone bipolar cells. A minority of ventral cones express S-opsin only, and they are selectively contacted by blue-cone bipolar cells. We suggest that these are genuine S-cones. In contrast to the other cones, their pedicles contain only low amounts of cone arrestin. The blue-cone bipolar cells of the mouse retina and their cone selectivity are closely similar to primate blue-cone bipolars, and we suggest that they both represent the phylogenetically ancient color system of the mammalian retina.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arrestin / metabolism
  • Cell Polarity
  • Color Perception*
  • In Vitro Techniques
  • Luminescent Proteins / genetics
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Recombinant Fusion Proteins / genetics
  • Retinal Cone Photoreceptor Cells / cytology*
  • Retinal Cone Photoreceptor Cells / metabolism
  • Rod Opsins / metabolism


  • Arrestin
  • Luminescent Proteins
  • Recombinant Fusion Proteins
  • Rod Opsins
  • clomeleon