A rhodopsin-like protein in Cyanophora paradoxa: gene sequence and protein immunolocalization

Frassanito, Anna Maria; Barsanti, Laura; Passarelli, Vincenzo; Evangelista, Valtere; Gualtieri, Paolo

doi:10.1007/s00018-009-0225-x

Cited by 19 publications

(13 citation statements)

References 30 publications

(33 reference statements)

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“…1). These genes are phylogenetically related to sensory rhodopsins that are involved in phototactic response in cryptophyte algae 13 and in the glaucophyte Cyanophora 14 , where the opsin localizes to the plastid. This scenario suggests that the Group 3 rhodopsins from O. marina were acquired from the ancestral photosynthetic endosymbiont 15 .…”

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confidence: 99%

A bacterial proteorhodopsin proton pump in marine eukaryotes

et al. 2011

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Proteorhodopsins are light-driven proton pumps involved in widespread phototrophy. Discovered in marine proteobacteria just 10 years ago, proteorhodopsins are now known to have been spread by lateral gene transfer across diverse prokaryotes, but are curiously absent from eukaryotes. In this study, we show that proteorhodopsins have been acquired by horizontal gene transfer from bacteria at least twice independently in dinoflagellate protists. We find that in the marine predator Oxyrrhis marina, proteorhodopsin is indeed the most abundantly expressed nuclear gene and its product localizes to discrete cytoplasmic structures suggestive of the endomembrane system. To date, photosystems I and II have been the only known mechanism for transducing solar energy in eukaryotes; however, it now appears that some abundant zooplankton use this alternative pathway to harness light to power biological functions.

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confidence: 99%

A bacterial proteorhodopsin proton pump in marine eukaryotes

et al. 2011

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“…However, DNA sequencing projects have been initiated only for a handful of phototactic algal species, therefore homology cloning of new channelopsins is required. Previously homology cloning has been successfully used by us (48) and others (49) to clone microbial opsin genes from the cryptophyte Cryptomonas and the glaucophyte Cyanophora , respectively. These genes, however, are not closely related to known channelopsins from green algae and do not confer ion channel activity when expressed in HEK cells (E. G. Govorunova and J. L. Spudich, unpublished observations).…”

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confidence: 99%

Diversity of Chlamydomonas Channelrhodopsins

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Govorunova

Ntefidou

et al. 2011

Photochem & Photobiology

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Channelrhodopsins act as photoreceptors for control of motility behavior in flagellates and are widely used as genetically targeted tools to optically manipulate the membrane potential of specific cell populations (“optogenetics”). The first two channelrhodopsins were obtained from the model organism Chlamydomonas reinhardtii (CrChR1 and CrChR2). By homology cloning we identified three new channelrhodopsin sequences from the same genus, CaChR1, CyChR1 and CraChR2, from C. augustae, C. yellowstonensis and C. raudensis, respectively. CaChR1 and CyChR1 were functionally expressed in HEK293 cells, where they acted as light-gated ion channels similar to CrChR1. However, both, which are similar to each other, differed from CrChR1 in current kinetics, inactivation, light intensity dependence, spectral sensitivity, and dependence on the external pH. These results show that extensive channelrhodopsin diversity exists even within the same genus, Chlamydomonas. The maximal spectral sensitivity of CaChR1 was at 520 nm at pH 7.4, about 40 nm red-shifted as compared to that of CrChR1 under the same conditions. CaChR1 was successfully expressed in Pichia pastoris and exhibited an absorption spectrum identical to the action spectrum of CaChR1-generated photocurrents. The red-shifted spectra and the lack of fast inactivation in CaChR1- and CyChR1-generated currents are features desirable for optogenetics applications.

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“…This alga has been examined extensively as a model organism of primitive phototrophs (e.g. Sato et al 2005, Watanabe et al 2009, Frassanito et al 2010, Leblond et al 2010, Facchinelli et al 2013. Ultrastructural features of C. paradoxa were examined using transmission and scanning electron microscopy (TEM and SEM, respectively) to demonstrate that the cell periphery lacks a cell wall but consists of plasma membrane and flattened vesicles containing a plate just underneath the membrane (Hall and Claus 1963, Mignot et al 1969, Trench et al 1978, Kies 1979, Kugrens et al 1999.…”

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confidence: 99%

Surface Ornamentation of <i>Cyanophora paradoxa</i> (Cyanophorales, Glaucophyta) Cells as Revealed by Ultra-High Resolution Field Emission Scanning Electron Microscopy

et al. 2014

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Summary Cyanophora paradoxa is an enigmatic biflagellate that may represent the first photosynthetic eukaryote morphologically. This alga has been widely studied as a model organism of primitive phototrophs. However, surface ornamentations of the vegetative cells have not been examined using ultra-high resolution field emission (FE) scanning electron microscopy (SEM). In the present study, C. paradoxa NIES-547 vegetative cells were examined using FE-SEM and compared with the data using conventional SEM. Our FE-SEM images demonstrated that the cell surface was ornamented with angular fenestrations framed by ridges. In contrast, conventional SEM did not reveal similar surface ornamentation. Transmission electron microscopy showed the ridge was formed by the edges of overlapping or attaching outermost plate vesicles at the cell periphery.

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A rhodopsin-like protein in Cyanophora paradoxa: gene sequence and protein immunolocalization

Cited by 19 publications

References 30 publications

A bacterial proteorhodopsin proton pump in marine eukaryotes

A bacterial proteorhodopsin proton pump in marine eukaryotes

Diversity of Chlamydomonas Channelrhodopsins

Surface Ornamentation of <i>Cyanophora paradoxa</i> (Cyanophorales, Glaucophyta) Cells as Revealed by Ultra-High Resolution Field Emission Scanning Electron Microscopy

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