TY - JOUR
T1 - Quantal noise from human red cone pigment
AU - Fu, Yingbin
AU - Kefalov, Vladimir
AU - Luo, Dong Gen
AU - Xue, Tian
AU - Yau, King Wai
N1 - Funding Information:
We thank J. Lai for help in generating the transgene construct, Y. Liang, L. Ding, and Y. Wang for mouse genotyping, J. Chen (University of Southern California School of Medicine) for the Gcaps–/– and Sag–/– mice and J. Lem (Tufts University School of Medicine) for the Rho–/– mice, as well as J. Nathans (Johns Hopkins University School of Medicine) and R. Molday (University of British Columbia) for their gifts of antibodies. We are indebted to P. Ala-Laurila, D. Baylor, and J. Schnapf for discussions. This work was supported by grant EY 06837 from the US National Eye Institute to K.-W.Y.
PY - 2008/5/29
Y1 - 2008/5/29
N2 - The rod pigment, rhodopsin, shows spontaneous isomerization activity. This quantal noise produces a dark light of ∼0.01 photons s-1 rod -1 in human, setting the threshold for rod vision. The spontaneous isomerization activity of human cone pigments has long remained a mystery because the effect of a single isomerized pigment molecule in cones, unlike that in rods, is small and beyond measurement. We have now overcome this problem by expressing human red cone pigment transgenically in mouse rods in order to exploit their large single-photon response, especially after genetic removal of a key negative-feedback regulation. Extrapolating the measured quantal noise of transgenic cone pigment to native human red cones, we obtained a dark rate of ∼10 false events s-1 cone-1, almost 10 3-fold lower than the overall dark transduction noise previously reported in primate cones. Our measurements provide a rationale for why mammalian red, green and blue cones have comparable sensitivities, unlike their amphibian counterparts.
AB - The rod pigment, rhodopsin, shows spontaneous isomerization activity. This quantal noise produces a dark light of ∼0.01 photons s-1 rod -1 in human, setting the threshold for rod vision. The spontaneous isomerization activity of human cone pigments has long remained a mystery because the effect of a single isomerized pigment molecule in cones, unlike that in rods, is small and beyond measurement. We have now overcome this problem by expressing human red cone pigment transgenically in mouse rods in order to exploit their large single-photon response, especially after genetic removal of a key negative-feedback regulation. Extrapolating the measured quantal noise of transgenic cone pigment to native human red cones, we obtained a dark rate of ∼10 false events s-1 cone-1, almost 10 3-fold lower than the overall dark transduction noise previously reported in primate cones. Our measurements provide a rationale for why mammalian red, green and blue cones have comparable sensitivities, unlike their amphibian counterparts.
UR - http://www.scopus.com/inward/record.url?scp=42649083664&partnerID=8YFLogxK
U2 - 10.1038/nn.2110
DO - 10.1038/nn.2110
M3 - Article
C2 - 18425122
AN - SCOPUS:42649083664
SN - 1097-6256
VL - 11
SP - 565
EP - 571
JO - Nature neuroscience
JF - Nature neuroscience
IS - 5
ER -