DOI: 10.5061/dryad.kv3j7
title: Data from: Cambrian origin of the CYP27C1-mediated vitamin A1-to-A2 switch, a key mechanism of vertebrate sensory plasticity

description: The spectral composition of ambient light varies across both space and
 time. Many species of jawed vertebrates adapt to this variation by tuning
 the sensitivity of their photoreceptors via the expression of CYP27C1, an
 enzyme that converts vitamin A1 into vitamin A2, thereby shifting the
 ratio of vitamin A1-based rhodopsin to red-shifted vitamin A2-based
 porphyropsin in the eye. Here, we show that the sea lamprey (Petromyzon
 marinus), a jawless vertebrate that diverged from jawed vertebrates during
 the Cambrian period (approx. 500 Ma), dynamically shifts its photoreceptor
 spectral sensitivity via vitamin A1-to-A2 chromophore exchange as it
 transitions between photically divergent aquatic habitats. We further show
 that this shift correlates with high-level expression of the lamprey
 orthologue of CYP27C1, specifically in the retinal pigment epithelium as
 in jawed vertebrates. Our results suggest that the CYP27C1-mediated
 vitamin A1-to-A2 switch is an evolutionarily ancient mechanism of sensory
 plasticity that appeared not long after the origin of vertebrates.
description: Lamprey_CYP27C1_qPCRData from qPCR analysis of Cyp27c1 expression in the retinal pigment epithelia of downstream juvenile and upstream migrant adult Petromyzon marinus.Lamprey_qPCR.csvFigure 2A - rod responsesMean responses of 13 rods to 20-ms 500-nm flashes given at t = 0 at the following intensities (in photons μm−2): 9, 40, 98, 366, 1055, and 2591.Figure2A_rodresponses.datFigure2B - cone responsesMean responses of 6 cones to 20-ms 600-nm flashes given at t = 0 at the following intensities (in photons μm−2): 78, 711, 2051, 5036, 1.91 × 10^4, 2.20 × 10^5, 6.71 × 10^5, and 6.96 × 10^5.Figure2B_coneresponses.datFigure2C - response intensity curvesNormalized mean current response amplitudes (± SE) as a function of flash intensity for rods and cones. Data for both cell types were fitted with the Michaelis-Menton equation, r/rmax = I/(I + I½) where r/rmax is the normalized current amplitude, I is the flash intensity, and I½ is the flash intensity producing a half-maximal response. Best-fitting values of I½ were 52 photons μm−2 for rods and 3210 photons μm−2 for cones.Figure2C_responseintensitycurves.datFigure3A - MSPMicrospectrophotometric determinations of mean pigment absorbance (± SE) normalized to absorbance at λmax, taken from 58 juvenile rods.Figure3A_MSP.datFigure3A - SSC plus fitSuction-electrode recordings of 9 juvenile rods and best-fitting A1 visual-pigment nomograms.Figure3A_SSCplusfit.datFigure3B - MSPMicrospectrophotometric determinations of mean pigment absorbance (± SE) normalized to absorbance at λmax, taken from 9 juvenile cones.Figure3B_MSP.datFigure3B - SSC plus fitSuction-electrode recordings of 7 juvenile cones and best-fitting A1 visual-pigment nomograms.Figure3B_SSCplusfit.datFigure3C - MSPmicrospectrophotometric determinations of mean pigment absorbance (± SE) normalized to absorbance at λmax, taken from 70 adult rods.Figure3C_MSP.datFigure3C - SSCSuction-electrode recordings of 13 adult rods and best-fitting A1 and A2 visual-pigment nomograms.Figure3C_SSC.datFigure3D - MSPMicrospectrophotometric determinations of mean pigment absorbance (± SE) normalized to absorbance at λmax, taken from 23 adult cones.Figure3D_MSP.datFigure3D_SSCSuction-electrode recordings of 14 adult cones and best-fitting A1 and A2 visual-pigment nomograms.Nanogram fitting scripts and dataThis archive contains the R scripts, functions, and data used to fit A1 and A2-based opsin visual pigment templates to miscrospectrophotometric measures of lamprey rod and cone photoreceptor absorbance spectra.Nanogram fitting.zip