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dc.contributor.authorMakino, Clint L.
dc.contributor.authorWen, Xiao-Hong
dc.contributor.authorMichaud, Norman A.
dc.contributor.authorCovington, Henry I.
dc.contributor.authorDiBenedetto, Emmanuele
dc.contributor.authorHamm, Heidi E.
dc.contributor.authorLem, Janis
dc.contributor.authorCaruso, Giovanni
dc.date.accessioned2013-03-14T18:24:34Z
dc.date.issued2012
dc.identifier.citationMakino, Clint L., Xiao-Hong Wen, Norman A. Michaud, Henry I. Covington, Emmanuele DiBenedetto, Heidi E. Hamm, Janis Lem, and Giovanni Caruso. 2012. Rhodopsin expression level affects rod outer segment morphology and photoresponse kinetics. PLoS ONE 7(5): e37832.en_US
dc.identifier.issn1932-6203en_US
dc.identifier.urihttp://nrs.harvard.edu/urn-3:HUL.InstRepos:10406318
dc.description.abstractBackground: The retinal rod outer segment is a sensory cilium that is specialized for the conversion of light into an electrical signal. Within the cilium, up to several thousand membranous disks contain as many as a billion copies of rhodopsin for efficient photon capture. Disks are continually turned over, requiring the daily synthesis of a prodigious amount of rhodopsin. To promote axial diffusion in the aqueous cytoplasm, the disks have one or more incisures. Across vertebrates, the range of disk diameters spans an order of magnitude, and the number and length of the incisures vary considerably, but the mechanisms controlling disk architecture are not well understood. The finding that transgenic mice overexpressing rhodopsin have enlarged disks lacking an incisure prompted us to test whether lowered rhodopsin levels constrain disk assembly. Methodology/Principal Findings: The structure and function of rods from hemizygous rhodopsin knockout (R+/−) mice with decreased rhodopsin expression were analyzed by transmission electron microscopy and single cell recording. R+/− rods were structurally altered in three ways: disk shape changed from circular to elliptical, disk surface area decreased, and the single incisure lengthened to divide the disk into two sections. Photocurrent responses to flashes recovered more rapidly than normal. A spatially resolved model of phototransduction indicated that changes in the packing densities of rhodopsin and other transduction proteins were responsible. The decrease in aqueous outer segment volume and the lengthened incisure had only minor effects on photon response amplitude and kinetics. Conclusions/Significance: Rhodopsin availability limits disk assembly and outer segment girth in normal rods. The incisure may buffer the supply of structural proteins needed to form larger disks. Decreased rhodopsin level accelerated photoresponse kinetics by increasing the rates of molecular collisions on the membrane. Faster responses, together with fewer rhodopsins, combine to lower overall sensitivity of R+/− rods to light.en_US
dc.language.isoen_USen_US
dc.publisherPublic Library of Scienceen_US
dc.relation.isversionofdoi:10.1371/journal.pone.0037832en_US
dc.relation.hasversionhttp://www.ncbi.nlm.nih.gov/pmc/articles/PMC3360601/pdf/en_US
dash.licenseLAA
dc.subjectBiologyen_US
dc.subjectAnatomy and Physiologyen_US
dc.subjectNeurological Systemen_US
dc.subjectSensory Physiologyen_US
dc.subjectBiochemistryen_US
dc.subjectCytochemistryen_US
dc.subjectCell Membraneen_US
dc.subjectMembrane Proteinsen_US
dc.subjectMembrane Structuresen_US
dc.subjectOrganellesen_US
dc.subjectNeuroscienceen_US
dc.subjectCellular Neuroscienceen_US
dc.subjectNeuronal Morphologyen_US
dc.subjectSensory Systemsen_US
dc.subjectVisual Systemen_US
dc.titleRhodopsin Expression Level Affects Rod Outer Segment Morphology and Photoresponse Kineticsen_US
dc.typeJournal Articleen_US
dc.description.versionVersion of Recorden_US
dc.relation.journalPLoS ONEen_US
dash.depositing.authorMakino, Clint L.
dc.date.available2013-03-14T18:24:34Z
dc.identifier.doi10.1371/journal.pone.0037832*
dash.contributor.affiliatedWen, Xiao-Hong
dash.contributor.affiliatedMakino, Clint L.


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