1
|
Nelson G, Strain A, Isu A, Rahnama A, Wakabayashi KI, Melvin AT, Kato N. Cells collectively migrate during ammonium chemotaxis in Chlamydomonas reinhardtii. Sci Rep 2023; 13:10781. [PMID: 37402785 DOI: 10.1038/s41598-023-36818-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 06/10/2023] [Indexed: 07/06/2023] Open
Abstract
The mechanisms governing chemotaxis in Chlamydomonas reinhardtii are largely unknown compared to those regulating phototaxis despite equal importance on the migratory response in the ciliated microalga. To study chemotaxis, we made a simple modification to a conventional Petri dish assay. Using the assay, a novel mechanism governing Chlamydomonas ammonium chemotaxis was revealed. First, we found that light exposure enhances the chemotactic response of wild-type Chlamydomonas strains, yet phototaxis-incompetent mutant strains, eye3-2 and ptx1, exhibit normal chemotaxis. This suggests that Chlamydomonas transduces the light signal pathway in chemotaxis differently from that in phototaxis. Second, we found that Chlamydomonas collectively migrate during chemotaxis but not phototaxis. Collective migration during chemotaxis is not clearly observed when the assay is conducted in the dark. Third, the Chlamydomonas strain CC-124 carrying agg1-, the AGGREGATE1 gene (AGG1) null mutation, exhibited a more robust collective migratory response than strains carrying the wild-type AGG1 gene. The expression of a recombinant AGG1 protein in the CC-124 strain suppressed this collective migration during chemotaxis. Altogether, these findings suggest a unique mechanism; ammonium chemotaxis in Chlamydomonas is mainly driven by collective cell migration. Furthermore, it is proposed that collective migration is enhanced by light and suppressed by the AGG1 protein.
Collapse
Affiliation(s)
- Gabela Nelson
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Alexis Strain
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Atsuko Isu
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Alireza Rahnama
- Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Ken-Ichi Wakabayashi
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Adam T Melvin
- Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Naohiro Kato
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA.
| |
Collapse
|
2
|
Seth K, Kumawat G, Vyas P, Harish. The structure and functional mechanism of eyespot in Chlamydomonas. J Basic Microbiol 2022; 62:1169-1178. [PMID: 35778815 DOI: 10.1002/jobm.202200249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 06/11/2022] [Accepted: 06/18/2022] [Indexed: 11/05/2022]
Abstract
Light plays a crucial role in photosynthesis, photoperiodism, and photomorphogenesis. Algae have a specialized visual system to perceive the light signal known as eyespot. A typical eyespot is an orange-colored, membranous structure packed with pigmented granules. In algae, the eyespot membrane bears a specialized type of photoreceptors, which shows similarity with animal rhodopsin photoreceptors. This light-sensing receptor is responsible for the photo-mobility response known as phototaxis. In this, light acts as a signal for onset and cascade of downstream signal transduction pathway leading to a conformational change in photoreceptor. This induces the continuous influx of calcium ions through the opening of calcium ion channels leading to membrane depolarization, and beating of flagella which is responsible for phototaxis. Mutational studies have assisted the discovery of eyespot genes, which are involved in eyespot development, assembly, size control, and functioning in Chlamydomonas. These genes belong to photoreceptors (cop1-12, acry, pcry, cry-dash1, cry-dash2, phot, uvr8), eyeless mutants (eye2, eye3), miniature-eyespot mutants (min1, min2), multiple eyespot mutants (mlt1, mlt2). This review discusses the structural biology of eyespots with special reference to Chlamydomonas, molecular insights, related genes, and proteins responsible for its proper functioning.
Collapse
Affiliation(s)
- Kunal Seth
- Department of Botany, Govt. Science College, Pardi Valsad, Gujarat, India
| | - Geetanjali Kumawat
- Plant Biotechnology Laboratory, Department of Botany, Mohanlal Sukhadia University, Udaipur, Rajasthan, India
| | - Pallavi Vyas
- Plant Biotechnology Laboratory, Department of Botany, Mohanlal Sukhadia University, Udaipur, Rajasthan, India
| | - Harish
- Plant Biotechnology Laboratory, Department of Botany, Mohanlal Sukhadia University, Udaipur, Rajasthan, India
| |
Collapse
|
3
|
Improved Productivity of Astaxanthin from Photosensitive Haematococcus pluvialis Using Phototaxis Technology. Mar Drugs 2022; 20:md20040220. [PMID: 35447893 PMCID: PMC9032356 DOI: 10.3390/md20040220] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 03/17/2022] [Accepted: 03/19/2022] [Indexed: 11/25/2022] Open
Abstract
Haematococcus pluvialis is a microalgae actively studied for the production of natural astaxanthin, which is a powerful antioxidant for human application. However, it is economically disadvantageous for commercialization owing to the low productivity of astaxanthin. This study reports an effective screening strategy using the negative phototaxis of the H. pluvialis to attain the mutants having high astaxanthin production. A polydimethylsiloxane (PDMS)-based microfluidic device irradiated with a specific light was developed to efficiently figure out the phototactic response of H. pluvialis. The partial photosynthesis deficient (PP) mutant (negative control) showed a 0.78-fold decreased cellular response to blue light compared to the wild type, demonstrating the positive relationship between the photosynthetic efficiency and the phototaxis. Based on this relationship, the Haematococcus mutants showing photosensitivity to blue light were selected from the 10,000 random mutant libraries. The M1 strain attained from the phototaxis-based screening showed 1.17-fold improved growth rate and 1.26-fold increases in astaxanthin production (55.12 ± 4.12 mg g−1) in the 100 L photo-bioreactor compared to the wild type. This study provides an effective selection tool for industrial application of the H. pluvialis with improved astaxanthin productivity.
Collapse
|
4
|
Pánek T, Barcytė D, Treitli SC, Záhonová K, Sokol M, Ševčíková T, Zadrobílková E, Jaške K, Yubuki N, Čepička I, Eliáš M. A new lineage of non-photosynthetic green algae with extreme organellar genomes. BMC Biol 2022; 20:66. [PMID: 35296310 PMCID: PMC8928634 DOI: 10.1186/s12915-022-01263-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 02/22/2022] [Indexed: 12/27/2022] Open
Abstract
Background The plastid genomes of the green algal order Chlamydomonadales tend to expand their non-coding regions, but this phenomenon is poorly understood. Here we shed new light on organellar genome evolution in Chlamydomonadales by studying a previously unknown non-photosynthetic lineage. We established cultures of two new Polytoma-like flagellates, defined their basic characteristics and phylogenetic position, and obtained complete organellar genome sequences and a transcriptome assembly for one of them. Results We discovered a novel deeply diverged chlamydomonadalean lineage that has no close photosynthetic relatives and represents an independent case of photosynthesis loss. To accommodate these organisms, we establish the new genus Leontynka, with two species (L. pallida and L. elongata) distinguishable through both their morphological and molecular characteristics. Notable features of the colourless plastid of L. pallida deduced from the plastid genome (plastome) sequence and transcriptome assembly include the retention of ATP synthase, thylakoid-associated proteins, the carotenoid biosynthesis pathway, and a plastoquinone-based electron transport chain, the latter two modules having an obvious functional link to the eyespot present in Leontynka. Most strikingly, the ~362 kbp plastome of L. pallida is by far the largest among the non-photosynthetic eukaryotes investigated to date due to an extreme proliferation of sequence repeats. These repeats are also present in coding sequences, with one repeat type found in the exons of 11 out of 34 protein-coding genes, with up to 36 copies per gene, thus affecting the encoded proteins. The mitochondrial genome of L. pallida is likewise exceptionally large, with its >104 kbp surpassed only by the mitogenome of Haematococcus lacustris among all members of Chlamydomonadales hitherto studied. It is also bloated with repeats, though entirely different from those in the L. pallida plastome, which contrasts with the situation in H. lacustris where both the organellar genomes have accumulated related repeats. Furthermore, the L. pallida mitogenome exhibits an extremely high GC content in both coding and non-coding regions and, strikingly, a high number of predicted G-quadruplexes. Conclusions With its unprecedented combination of plastid and mitochondrial genome characteristics, Leontynka pushes the frontiers of organellar genome diversity and is an interesting model for studying organellar genome evolution. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-022-01263-w.
Collapse
Affiliation(s)
- Tomáš Pánek
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, 701 00, Ostrava, Czech Republic.,Department of Zoology, Faculty of Science, Charles University, 128 43, Prague, Czech Republic
| | - Dovilė Barcytė
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, 701 00, Ostrava, Czech Republic
| | - Sebastian C Treitli
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, 252 42, Vestec, Czech Republic
| | - Kristína Záhonová
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, 701 00, Ostrava, Czech Republic
| | - Martin Sokol
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, 701 00, Ostrava, Czech Republic
| | - Tereza Ševčíková
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, 701 00, Ostrava, Czech Republic
| | - Eliška Zadrobílková
- Department of Zoology, Faculty of Science, Charles University, 128 43, Prague, Czech Republic
| | - Karin Jaške
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, 701 00, Ostrava, Czech Republic
| | - Naoji Yubuki
- Department of Zoology, Faculty of Science, Charles University, 128 43, Prague, Czech Republic.,Bioimaging Facility, University of British Columbia, Vancouver, V6T 1Z4, Canada
| | - Ivan Čepička
- Department of Zoology, Faculty of Science, Charles University, 128 43, Prague, Czech Republic
| | - Marek Eliáš
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, 701 00, Ostrava, Czech Republic.
| |
Collapse
|
5
|
Channelrhodopsin-Dependent Photo-Behavioral Responses in the Unicellular Green Alga Chlamydomonas reinhardtii. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1293:21-33. [PMID: 33398805 DOI: 10.1007/978-981-15-8763-4_2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Channelrhodopsins (ChRs) are the light-gated ion channels that have opened the research field of optogenetics. They were originally identified in the green alga Chlamydomonas reinhardtii, a biciliated unicellular alga that inhabits in freshwater, swims with the cilia, and undergoes photosynthesis. It has various advantages as an experimental organism and is used in a wide range of research fields including photosynthesis, cilia, and sexual reproduction. ChRs function as the primary photoreceptor for the cell's photo-behavioral responses, seen as changes in the manner of swimming after photoreception. In this chapter, we will introduce C. reinhardtii as an experimental organism and explain our current understanding of how the cell senses light and shows photo-behavioral responses.
Collapse
|
6
|
Yu K, Liu P, Venkatachalam D, Hopkinson BM, Lechtreck KF. The BBSome restricts entry of tagged carbonic anhydrase 6 into the cis-flagellum of Chlamydomonas reinhardtii. PLoS One 2020; 15:e0240887. [PMID: 33119622 PMCID: PMC7595284 DOI: 10.1371/journal.pone.0240887] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 10/05/2020] [Indexed: 01/12/2023] Open
Abstract
The two flagella of Chlamydomonas reinhardtii are of the same size and structure but display functional differences, which are critical for flagellar steering movements. However, biochemical differences between the two flagella have not been identified. Here, we show that fluorescence protein-tagged carbonic anhydrase 6 (CAH6-mNG) preferentially localizes to the trans-flagellum, which is organized by the older of the two flagella-bearing basal bodies. The uneven distribution of CAH6-mNG is established early during flagellar assembly and restored after photobleaching, suggesting that it is based on preferred entry or retention of CAH6-mNG in the trans-flagellum. Since CAH6-mNG moves mostly by diffusion, a role of intraflagellar transport (IFT) in establishing its asymmetric distribution is unlikely. Interestingly, CAH6-mNG is present in both flagella of the non-phototactic bardet-biedl syndrome 1 (bbs1) mutant revealing that the BBSome is involved in establishing CAH6-mNG flagellar asymmetry. Using dikaryon rescue experiments, we show that the de novo assembly of CAH6-mNG in flagella is considerably faster than the removal of ectopic CAH6-mNG from bbs flagella. Thus, different rates of flagellar entry of CAH6-mNG rather than its export from flagella is the likely basis for its asymmetric distribution. The data identify a novel role for the C. reinhardtii BBSome in preventing the entry of CAH6-mNG specifically into the cis-flagellum.
Collapse
Affiliation(s)
- Kewei Yu
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Peiwei Liu
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Dipna Venkatachalam
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Brian M. Hopkinson
- Department of Marine Sciences, University of Georgia, Athens, Georgia, United States of America
| | - Karl F. Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
| |
Collapse
|
7
|
Pick U, Zarka A, Boussiba S, Davidi L. A hypothesis about the origin of carotenoid lipid droplets in the green algae Dunaliella and Haematococcus. PLANTA 2019; 249:31-47. [PMID: 30470898 DOI: 10.1007/s00425-018-3050-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 11/14/2018] [Indexed: 05/20/2023]
Abstract
Hypercarotenogenesis in green algae evolved by mutation of PSY that increased its transcription at high light, disintegration of the eyespot in Dunaliella and acquisition of the capacity to export carotenoids from chloroplasts in Haematococcus. Carotenoids (Car) are lipid-soluble pigments synthesized in plants, algae, bacteria and fungi. Car have strong antioxidative properties and as such are utilized to reduce the danger of different diseases in humans. Two green microalgae are utilized as rich natural sources for Car: Dunaliella salina/bardawil accumulates 10% (w/w) β-carotene (βC), which is also pro-vitamin A, and Haematococcus pluvialis accumulates 4% (w/w) astaxanthin (Ast), the strongest antioxidant among Car. D. bardawil accumulates βC in plastoglobules within the chloroplast, whereas H. pluvialis deposits Ast in cytoplasmic lipid droplets (CLD). In this review we compare the hypercarotenogenic responses (HCR) in Dunaliella and in Haematococcus and try to outline hypothetical evolutionary pathways for its origin. We propose that a mutation in phytoene synthetase that increased its transcription level in response to high light stress had a pivotal role in the evolution of the HCR. Proteomic analyses indicated that in D. bardawil/salina the HCR evolved from dissociation and amplification of eyespot lipid globules. The more robust HCR in algae that accumulate carotenoids in CLD, such as H. pluvialis, required also acquisition of the capacity to export βC out of the chloroplast and its enzymatic conversion into Ast.
Collapse
Affiliation(s)
- Uri Pick
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 76100, Rehovot, Israel.
| | - Aliza Zarka
- Microalgal Biotechnology Laboratory, French Associates Institute for Agriculture and Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede-Boker Campus, Beer-Sheva, 8499000, Israel
| | - Sammy Boussiba
- Microalgal Biotechnology Laboratory, French Associates Institute for Agriculture and Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede-Boker Campus, Beer-Sheva, 8499000, Israel
| | - Lital Davidi
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095-1569, USA
| |
Collapse
|
8
|
Chlamydomonas Basal Bodies as Flagella Organizing Centers. Cells 2018; 7:cells7070079. [PMID: 30018231 PMCID: PMC6070942 DOI: 10.3390/cells7070079] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 07/09/2018] [Accepted: 07/10/2018] [Indexed: 11/17/2022] Open
Abstract
During ciliogenesis, centrioles convert to membrane-docked basal bodies, which initiate the formation of cilia/flagella and template the nine doublet microtubules of the flagellar axoneme. The discovery that many human diseases and developmental disorders result from defects in flagella has fueled a strong interest in the analysis of flagellar assembly. Here, we will review the structure, function, and development of basal bodies in the unicellular green alga Chlamydomonas reinhardtii, a widely used model for the analysis of basal bodies and flagella. Intraflagellar transport (IFT), a flagella-specific protein shuttle critical for ciliogenesis, was first described in C. reinhardtii. A focus of this review will be on the role of the basal bodies in organizing the IFT machinery.
Collapse
|
9
|
Eyespot-dependent determination of the phototactic sign in Chlamydomonas reinhardtii. Proc Natl Acad Sci U S A 2016; 113:5299-304. [PMID: 27122315 DOI: 10.1073/pnas.1525538113] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The biflagellate green alga Chlamydomonas reinhardtii exhibits both positive and negative phototaxis to inhabit areas with proper light conditions. It has been shown that treatment of cells with reactive oxygen species (ROS) reagents biases the phototactic sign to positive, whereas that with ROS scavengers biases it to negative. Taking advantage of this property, we isolated a mutant, lts1-211, which displays a reduction-oxidation (redox) dependent phototactic sign opposite to that of the wild type. This mutant has a single amino acid substitution in phytoene synthase, an enzyme that functions in the carotenoid-biosynthesis pathway. The eyespot contains large amounts of carotenoids and is crucial for phototaxis. Most lts1-211 cells have no detectable eyespot and reduced carotenoid levels. Interestingly, the reversed phototactic-sign phenotype of lts1-211 is shared by other eyespot-less mutants. In addition, we directly showed that the cell body acts as a convex lens. The lens effect of the cell body condenses the light coming from the rear onto the photoreceptor in the absence of carotenoid layers, which can account for the reversed-phototactic-sign phenotype of the mutants. These results suggest that light-shielding property of the eyespot is essential for determination of phototactic sign.
Collapse
|
10
|
Mittelmeier TM, Thompson MD, Lamb MR, Lin H, Dieckmann CL. MLT1 links cytoskeletal asymmetry to organelle placement in chlamydomonas. Cytoskeleton (Hoboken) 2015; 72:113-23. [PMID: 25809438 DOI: 10.1002/cm.21220] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 03/16/2015] [Accepted: 03/18/2015] [Indexed: 11/08/2022]
Abstract
Asymmetric placement of the photosensory eyespot organelle in Chlamydomonas is patterned by mother-daughter differences between the two basal bodies, which template the anterior flagella. Each basal body is associated with two bundled microtubule rootlets, one with two microtubules and one with four, forming a cruciate pattern. In wild-type cells, the single eyespot is positioned at the equator in close proximity to the plus end of the daughter rootlet comprising four microtubules, the D4. Here we identify mutations in two linked loci, MLT1 and MLT2, which cause multiple eyespots. Antiserum raised against MLT1 localized the protein along the D4 rootlet microtubules, from the basal bodies to the eyespot. MLT1 associates immediately with the new D4 as it extends during cell division, before microtubule acetylation. MLT1 is a low-complexity protein of over 300,000 Daltons. The expression or stability of MLT1 is dependent on MLT2, predicted to encode a second large, low-complexity protein. MLT1 was not restricted to the D4 rootlet in cells with the vfl2-220 mutation in the gene encoding the basal body-associated protein centrin. The cumulative data highlight the role of mother-daughter basal body differences in establishing asymmetry in associated rootlets, and suggest that eyespot components are directed to the correct location by MLT1 on the D4 microtubules.
Collapse
Affiliation(s)
- Telsa M Mittelmeier
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona
| | | | | | | | | |
Collapse
|
11
|
Eitzinger N, Wagner V, Weisheit W, Geimer S, Boness D, Kreimer G, Mittag M. Proteomic Analysis of a Fraction with Intact Eyespots of Chlamydomonas reinhardtii and Assignment of Protein Methylation. FRONTIERS IN PLANT SCIENCE 2015; 6:1085. [PMID: 26697039 PMCID: PMC4678213 DOI: 10.3389/fpls.2015.01085] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 11/19/2015] [Indexed: 05/22/2023]
Abstract
Flagellate green algae possess a visual system, the eyespot. In Chlamydomonas reinhardtii it is situated at the edge of the chloroplast and consists of two carotenoid rich lipid globule layers subtended by thylakoid membranes (TM) that are attached to both chloroplast envelope membranes and a specialized area of the plasma membrane (PM). A former analysis of an eyespot fraction identified 203 proteins. To increase the understanding of eyespot related processes, knowledge of the protein composition of the membranes in its close vicinity is desirable. Here, we present a purification procedure that allows isolation of intact eyespots. This gain in intactness goes, however, hand in hand with an increase of contaminants from other organelles. Proteomic analysis identified 742 proteins. Novel candidates include proteins for eyespot development, retina-related proteins, ion pumps, and membrane-associated proteins, calcium sensing proteins as well as kinases, phosphatases and 14-3-3 proteins. Methylation of proteins at Arg or Lys is known as an important posttranslational modification involved in, e.g., signal transduction. Here, we identify several proteins from eyespot fractions that are methylated at Arg and/or Lys. Among them is the eyespot specific SOUL3 protein that influences the size and position of the eyespot and EYE2, a protein important for its development.
Collapse
Affiliation(s)
- Nicole Eitzinger
- Cell Biology, Department of Biology, Friedrich-Alexander-University Erlangen-NurembergErlangen, Germany
| | - Volker Wagner
- Institute of General Botany and Plant Physiology, Faculty of Biology and Pharmacy, Friedrich Schiller University JenaJena, Germany
| | - Wolfram Weisheit
- Institute of General Botany and Plant Physiology, Faculty of Biology and Pharmacy, Friedrich Schiller University JenaJena, Germany
| | - Stefan Geimer
- Cell Biology and Electron Microscopy, University of BayreuthBayreuth, Germany
| | - David Boness
- Cell Biology, Department of Biology, Friedrich-Alexander-University Erlangen-NurembergErlangen, Germany
| | - Georg Kreimer
- Cell Biology, Department of Biology, Friedrich-Alexander-University Erlangen-NurembergErlangen, Germany
| | - Maria Mittag
- Institute of General Botany and Plant Physiology, Faculty of Biology and Pharmacy, Friedrich Schiller University JenaJena, Germany
- *Correspondence: Maria Mittag,
| |
Collapse
|
12
|
Tenenboim H, Smirnova J, Willmitzer L, Steup M, Brotman Y. VMP1-deficient Chlamydomonas exhibits severely aberrant cell morphology and disrupted cytokinesis. BMC PLANT BIOLOGY 2014; 14:121. [PMID: 24885763 PMCID: PMC4108031 DOI: 10.1186/1471-2229-14-121] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 04/28/2014] [Indexed: 05/20/2023]
Abstract
BACKGROUND The versatile Vacuole Membrane Protein 1 (VMP1) has been previously investigated in six species. It has been shown to be essential in macroautophagy, where it takes part in autophagy initiation. In addition, VMP1 has been implicated in organellar biogenesis; endo-, exo- and phagocytosis, and protein secretion; apoptosis; and cell adhesion. These roles underly its proven involvement in pancreatitis, diabetes and cancer in humans. RESULTS In this study we analyzed a VMP1 homologue from the green alga Chlamydomonas reinhardtii. CrVMP1 knockdown lines showed severe phenotypes, mainly affecting cell division as well as the morphology of cells and organelles. We also provide several pieces of evidence for its involvement in macroautophagy. CONCLUSION Our study adds a novel role to VMP1's repertoire, namely the regulation of cytokinesis. Though the directness of the observed effects and the mechanisms underlying them remain to be defined, the protein's involvement in macroautophagy in Chlamydomonas, as found by us, suggests that CrVMP1 shares molecular characteristics with its animal and protist counterparts.
Collapse
Affiliation(s)
- Hezi Tenenboim
- Institute of Biochemistry and Biology, Department of Plant Physiology, Universität Potsdam, Potsdam, Germany
- Max Planck Institute for Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Julia Smirnova
- Max Planck Institute for Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Lothar Willmitzer
- Max Planck Institute for Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Martin Steup
- Institute of Biochemistry and Biology, Department of Plant Physiology, Universität Potsdam, Potsdam, Germany
| | - Yariv Brotman
- Max Planck Institute for Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam, Germany
| |
Collapse
|
13
|
Independent localization of plasma membrane and chloroplast components during eyespot assembly. EUKARYOTIC CELL 2013; 12:1258-70. [PMID: 23873865 DOI: 10.1128/ec.00111-13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Like many algae, Chlamydomonas reinhardtii is phototactic, using two anterior flagella to swim toward light optimal for photosynthesis. The flagella are responsive to signals initiated at the photosensory eyespot, which comprises photoreceptors in the plasma membrane and layers of pigment granules in the chloroplast. Phototaxis depends on placement of the eyespot at a specific asymmetric location relative to the flagella, basal bodies, and bundles of two or four highly acetylated microtubules, termed rootlets, which extend from the basal bodies toward the posterior of the cell. Previous work has shown that the eyespot is disassembled prior to cell division, and new eyespots are assembled in daughter cells adjacent to the nascent four-membered rootlet associated with the daughter basal body (D4), but the chronology of these assembly events has not been determined. Here we use immunofluorescence microscopy to follow assembly and acetylation of the D4 rootlet, localization of individual eyespot components in the plasma membrane or chloroplast envelope, and flagellar emergence during and immediately following cell division. We find that the D4 rootlet is assembled before the initiation of eyespot assembly, which occurs within the same time frame as rootlet acetylation and flagellar outgrowth. Photoreceptors in the plasma membrane are correctly localized in eyespot mutant cells lacking pigment granule layers, and chloroplast components of the eyespot assemble in mutant cells in which photoreceptor localization is retarded. The data suggest that plasma membrane and chloroplast components of the eyespot are independently responsive to a cytoskeletal positioning cue.
Collapse
|
14
|
Schulze T, Schreiber S, Iliev D, Boesger J, Trippens J, Kreimer G, Mittag M. The heme-binding protein SOUL3 of Chlamydomonas reinhardtii influences size and position of the eyespot. MOLECULAR PLANT 2013; 6:931-944. [PMID: 23180671 DOI: 10.1093/mp/sss137] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The flagellated green alga Chlamydomonas reinhardtii has a primitive visual system, the eyespot. It is situated at the cells equator and allows the cell to phototax. In a previous proteomic analysis of the eyespot, the SOUL3 protein was identified among 202 proteins. Here, we investigate the properties and functions of SOUL3. Heterologously expressed SOUL3 is able to bind specifically to hemin. In C. reinhardtii, SOUL3 is expressed at a constant level over the diurnal cycle, but forms protein complexes that differ in size during day and night phases. SOUL3 is primarily localized in the eyespot and it is situated in the pigment globule layer thereof. This is in contrast to the channelrhodopsin photoreceptors, which are localized in the plasma membrane region of the eyespot. Knockdown lines with a significantly reduced SOUL3 level are characterized by mislocalized eyespots, a decreased eyespot size, and alterations in phototactic behavior. Mislocalizations were either anterior or posterior and did not affect association with acetylated microtubules of the daughter four-membered rootlet. Our data suggest that SOUL3 is involved in the organization and placement of the eyespot within the cell.
Collapse
Affiliation(s)
- Thomas Schulze
- Institute of General Botany and Plant Physiology, Friedrich Schiller University Jena, 07743 Jena, Germany
| | | | | | | | | | | | | |
Collapse
|
15
|
Channelrhodopsins-Their potential in gene therapy for neurological disorders. Neurosci Res 2012; 75:6-12. [PMID: 23026479 DOI: 10.1016/j.neures.2012.09.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 08/18/2012] [Accepted: 09/10/2012] [Indexed: 11/23/2022]
Abstract
Recently, channelrhodopsins (ChRs) have begun to be used to manipulate the neuronal activity, since they can be targeted to specific neurons or neural circuits using genetic methods. To advance the potential applications in the investigation and treatment of neurological disorders, the following types of basic research should receive extensive financial support. The spectral and kinetic properties of ChRs should be optimized according to the application by generating variants of ChRs or exploring new rhodopsins from other species. These ChRs should be targeted to the specific types of neurons involved in the neurological disorders through a gene expression system using cell- or tissue-specific promoters/enhancers as well as gene delivery systems with modified virus vectors. The methods have to be developed to apply the genes of interest with safety and long-term effectiveness. Sophisticated opto-electrical devices should be developed. Appropriate primate animal model systems should be established to minimize the structural differences between small animals such as rodents and human beings. In this paper, we will review the current progress in the basic research concerned with the potential clinical application of ChRs and discuss the future directions of research on ChRs so that they could be applied for human welfare.
Collapse
|
16
|
Miniature- and Multiple-Eyespot Loci in Chlamydomonas reinhardtii Define New Modulators of Eyespot Photoreception and Assembly. G3-GENES GENOMES GENETICS 2011; 1:489-98. [PMID: 22384359 PMCID: PMC3276157 DOI: 10.1534/g3.111.000679] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 09/23/2011] [Indexed: 12/02/2022]
Abstract
The photosensory eyespot of the green alga Chlamydomonas reinhardtii is a model system for the study of organelle biogenesis and placement. Eyespot assembly and positioning are governed by several genetic loci that have been identified in forward genetic screens for phototaxis-defective mutants. These include the previously described miniature-eyespot mutant min1, the multiple-eyespot mutant mlt1, the eyeless mutants eye2 and eye3, and two previously uncharacterized eyespot mutants, min2 and mlt2. In this study, effects of miniature- and multiple-eyespot mutations and their combinations on the localization and expression levels of the rhodopsin photoreceptor channelrhodopsin-1 (ChR1) and the localization of the eyespot-assembly proteins EYE2 and EYE3 were examined. min2 mutants assemble a properly organized, albeit nonfunctional, eyespot that is slightly smaller than wild-type; however, combination of the min2 and mlt1 mutations resulted in drastic reduction of photoreceptor levels. Both stationary-phase mlt1 and mlt2 cells have supernumerary, mislocalized eyespots that exhibit partial or total dissociation of the eyespot layers. In these mutant strains, photoreceptor patches in the plasma membrane were never associated with pigment granule arrays in the chloroplast stroma unless EYE2 was present in the intervening envelope. The data suggest that MIN2 is required for the photoreceptive ability of the eyespot and that MLT2 plays a major role in regulating eyespot number, placement, and integrity.
Collapse
|
17
|
Boyd JS, Gray MM, Thompson MD, Horst CJ, Dieckmann CL. The daughter four-membered microtubule rootlet determines anterior-posterior positioning of the eyespot in Chlamydomonas reinhardtii. Cytoskeleton (Hoboken) 2011; 68:459-69. [PMID: 21766471 PMCID: PMC3201734 DOI: 10.1002/cm.20524] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Revised: 06/07/2011] [Accepted: 07/07/2011] [Indexed: 11/06/2022]
Abstract
The characteristic geometry of the unicellular chlorophyte Chlamydomonas reinhardtii has contributed to its adoption as a model system for cellular asymmetry and organelle positioning. The eyespot, a photosensitive organelle, is localized asymmetrically in the cell at a precisely defined position relative to the flagella and cytoskeletal microtubule rootlets. We have isolated a mutant, named pey1 for posterior eyespot, with variable microtubule rootlet lengths. The length of the acetylated daughter four-membered (D4) microtubule rootlet correlates with the position of the eyespot, which appears in a posterior position in the majority of cells. The correlation of rootlet length with eyespot positioning was also observed in the cmu1 mutant, which has longer acetylated microtubules, and the mlt1 mutant, in which the rootlet microtubules are shorter. Observation of eyespot positioning after depolymerization of rootlet microtubules indicated that eyespot position is fixed early in eyespot development and becomes independent of the rootlet. Our data demonstrate that the length of the D4 rootlet is the major determinant of eyespot positioning on the anterior-posterior axis and are suggestive that the gene product of the PEY1 locus is a novel regulator of acetylated microtubule length.
Collapse
Affiliation(s)
- Joseph S. Boyd
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona 85721
| | - Miranda M. Gray
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona 85721
| | - Mark D. Thompson
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona 85721
| | - Cynthia J. Horst
- Department of Biology, Carroll University, Waukesha, Wisconsin 53186
| | - Carol L. Dieckmann
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona 85721
| |
Collapse
|
18
|
Dieckmann C. Carol Dieckmann: an eye on organellar biology. Interview by Caitlin Sedwick. J Cell Biol 2011; 194:4-5. [PMID: 21746849 PMCID: PMC3135401 DOI: 10.1083/jcb.1941pi] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Carol Dieckmann studies the Chlamydomonas eyespot and mitochondrial gene expression.
Collapse
|
19
|
Boyd JS, Mittelmeier TM, Dieckmann CL. New insights into eyespot placement and assembly in Chlamydomonas. BIOARCHITECTURE 2011; 1:196-199. [PMID: 22069514 DOI: 10.4161/bioa.1.4.17697] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Revised: 08/04/2011] [Accepted: 08/06/2011] [Indexed: 12/29/2022]
Abstract
Aspects of cellular architecture, such as cytoskeletal asymmetry cues, play critical roles in directing the placement of organelles and establishing the sites of their formation. In the model green alga Chlamydomonas, the photosensory eyespot occupies a defined position in relation to the flagella and microtubule cytoskeleton. Investigations into the cellular mechanisms of eyespot placement and assembly have aided our understanding of the interplay between cytoskeletal and plastid components of the cell. The eyespot, which must be assembled anew after each cell division, is a multi-layered organelle consisting of stacks of carotenoid-filled pigment granules in the chloroplast and rhodopsin photoreceptors in the plasma membrane. Placement of the eyespot is determined on both the latitudinal and longitudinal axes of the cell by the daughter four-membered (D4) microtubule rootlet. Recent findings have contributed to the hypothesis that the eyespot photoreceptor molecules are directed from the Golgi to the daughter hemisphere of the cell and trafficked along the D4 microtubule rootlet. EYE2, a chloroplast-envelope protein, forms an elliptical patch together with the photoreceptors and establishes the site for assembly of the pigment granule arrays in the chloroplast, connecting the positioning information of the cytoskeleton to assembly of the pigment granule arrays in the chloroplast.
Collapse
Affiliation(s)
- Joseph S Boyd
- Department of Molecular and Cellular Biology; University of Arizona; Tucson, AZ USA
| | | | | |
Collapse
|
20
|
Mittelmeier TM, Boyd JS, Lamb MR, Dieckmann CL. Asymmetric properties of the Chlamydomonas reinhardtii cytoskeleton direct rhodopsin photoreceptor localization. J Cell Biol 2011; 193:741-53. [PMID: 21555459 PMCID: PMC3166873 DOI: 10.1083/jcb.201009131] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Accepted: 04/06/2011] [Indexed: 11/22/2022] Open
Abstract
The eyespot of the unicellular green alga Chlamydomonas reinhardtii is a photoreceptive organelle required for phototaxis. Relative to the anterior flagella, the eyespot is asymmetrically positioned adjacent to the daughter four-membered rootlet (D4), a unique bundle of acetylated microtubules extending from the daughter basal body toward the posterior of the cell. Here, we detail the relationship between the rhodopsin eyespot photoreceptor Channelrhodopsin 1 (ChR1) and acetylated microtubules. In wild-type cells, ChR1 was observed in an equatorial patch adjacent to D4 near the end of the acetylated microtubules and along the D4 rootlet. In cells with cytoskeletal protein mutations, supernumerary ChR1 patches remained adjacent to acetylated microtubules. In mlt1 (multieyed) mutant cells, supernumerary photoreceptor patches were not restricted to the D4 rootlet, and more anterior eyespots correlated with shorter acetylated microtubule rootlets. The data suggest a model in which photoreceptor localization is dependent on microtubule-based trafficking selective for the D4 rootlet, which is perturbed in mlt1 mutant cells.
Collapse
Affiliation(s)
- Telsa M. Mittelmeier
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721
| | - Joseph S. Boyd
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721
| | - Mary Rose Lamb
- Department of Biology, University of Puget Sound, Tacoma, WA 98416
| | - Carol L. Dieckmann
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721
| |
Collapse
|
21
|
Boyd JS, Mittelmeier TM, Lamb MR, Dieckmann CL. Thioredoxin-family protein EYE2 and Ser/Thr kinase EYE3 play interdependent roles in eyespot assembly. Mol Biol Cell 2011; 22:1421-9. [PMID: 21372178 PMCID: PMC3084665 DOI: 10.1091/mbc.e10-11-0918] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
EYE2 is a key protein in connecting the positioning information of the microtubule rootlet cytoskeleton and channelrhodopsin 1 (ChR1) photoreceptor to the formation and positioning of the eyespot pigment granules in the chloroplast of Chlamydomonas. EYE3, a ser/thr kinase of the ABC1 family, is found in pigment granules and is required for their biogenesis. The eyespot of the biflagellate unicellular green alga Chlamydomonas reinhardtii is a complex organelle that facilitates directional responses of the cell to environmental light stimuli. The eyespot, which assembles de novo after every cell division and is associated with the daughter four-membered (D4) microtubule rootlet, comprises an elliptical patch of rhodopsin photoreceptors on the plasma membrane and stacks of carotenoid-rich pigment granule arrays in the chloroplast. Two loci, EYE2 and EYE3, define factors involved in the formation and organization of the eyespot pigment granule arrays. Whereas EYE3, a serine/threonine kinase of the ABC1 family, localizes to pigment granules, EYE2 localization corresponds to an area of the chloroplast envelope in the eyespot. EYE2 is positioned along, and adjacent to, the D4 rootlet in the absence of pigment granules. The eyespot pigment granule array is required for maintenance of the elliptical shape of both the overlying EYE2 and channelrhodopsin-1 photoreceptor patches. We propose a model of eyespot assembly wherein rootlet and photoreceptor direct EYE2 to an area of the chloroplast envelope, where it acts to facilitate assembly of pigment granule arrays, and EYE3 plays a role in the biogenesis of the pigment granules.
Collapse
Affiliation(s)
- Joseph S Boyd
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721, USA
| | | | | | | |
Collapse
|
22
|
Kreimer G. The green algal eyespot apparatus: a primordial visual system and more? Curr Genet 2008; 55:19-43. [PMID: 19107486 DOI: 10.1007/s00294-008-0224-8] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2008] [Revised: 11/28/2008] [Accepted: 12/02/2008] [Indexed: 10/21/2022]
Abstract
Most flagellate green algae exhibiting phototaxis posses a singular specialized light sensitive organelle, the eyespot apparatus (EA). Its design principles are similar in all green algae and produce, in conjunction with the movement pattern of the cell, a highly directional optical device. It enables an oriented movement response with respect to the direction and intensity of light. The functional EA involves local specializations of different compartments (plasma membrane, cytosol, and chloroplast) and utilizes specialized microbial-type rhodopsins, which act as directly light-gated ion channels. Due to their elaborate structures and the presence of retinal-based photoreceptors in some lineages, algal EAs are thought to play an important role in the evolution of photoreception and are thus not only of interest to plant biologists. In green algae considerable progress in the molecular dissection of components of this primordial visual system has been made by genetic and proteomic approaches in recent years. This review summarizes general aspects of the green algal EA as well as recent progress in the identification of proteins related to it. Further, novel data supporting a link between eyespot globules and plastoglobules will be presented and potential additional roles of the EA besides those in photoreception will be discussed.
Collapse
Affiliation(s)
- Georg Kreimer
- Department Biologie, Friedrich-Alexander Universität Erlangen, 91058, Erlangen, Germany.
| |
Collapse
|
23
|
Inwood W, Yoshihara C, Zalpuri R, Kim KS, Kustu S. The ultrastructure of a Chlamydomonas reinhardtii mutant strain lacking phytoene synthase resembles that of a colorless alga. MOLECULAR PLANT 2008; 1:925-37. [PMID: 19825593 PMCID: PMC2902904 DOI: 10.1093/mp/ssn046] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Chlamydomonas reinhardtii strains lacking phytoene synthase, the first enzyme of carotenoid biosynthesis, are white. They lack carotenoid pigments, have very low levels of chlorophyll, and can grow only heterotrophically in the dark. Our electron and fluorescence microscopic studies showed that such a mutant strain (lts1-204) had a proliferated plastid envelope membrane but no stacks of thylakoid membranes within the plastid. It accumulated cytoplasmic compartments that appeared to be autophagous vacuoles filled with membranous material. The lts1 mutants apparently lacked pyrenoid bodies, which normally house ribulose bisphosphate carboxylase-oxygenase (Rubisco), and accumulated many starch granules. Although these mutant strains cannot synthesize the carotenoid and carotenoid-derived pigments present in the phototactic organelle (eyespot), the mutant we examined made a vestigial eyespot that was disorganized and often mislocalized to the posterior end of the cell. The absence of a pyrenoid body, the accumulation of starch, and the disorganization of the eyespot may all result from the absence of thylakoids. The ultrastructure of lts1 mutant strains is similar to but distinct from that of previously described white and yellow mutant strains of C. reinhardtii and is similar to that of naturally colorless algae of the Polytoma group.
Collapse
Affiliation(s)
- William Inwood
- Department of Plant and Microbial Biology, 111 Koshland Hall, University of California, Berkeley, CA 94720–3102, USA
| | - Corinne Yoshihara
- Department of Plant and Microbial Biology, 111 Koshland Hall, University of California, Berkeley, CA 94720–3102, USA
| | - Reena Zalpuri
- Electron Microscope Laboratory, 26 Giannini Hall, University of California, Berkeley, CA 94720–3330, USA
| | - Kwang-Seo Kim
- Department of Plant and Microbial Biology, 111 Koshland Hall, University of California, Berkeley, CA 94720–3102, USA
| | - Sydney Kustu
- Department of Plant and Microbial Biology, 111 Koshland Hall, University of California, Berkeley, CA 94720–3102, USA
- To whom correspondence should be addressed. E-mail , fax (510) 642-4995, tel. (510) 643-9308
| |
Collapse
|
24
|
C2 domain protein MIN1 promotes eyespot organization in Chlamydomonas reinhardtii. EUKARYOTIC CELL 2008; 7:2100-12. [PMID: 18849467 DOI: 10.1128/ec.00118-08] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Assembly and asymmetric localization of the photosensory eyespot in the biflagellate, unicellular green alga Chlamydomonas reinhardtii requires coordinated organization of photoreceptors in the plasma membrane and pigment granule/thylakoid membrane layers in the chloroplast. min1 (mini-eyed) mutant cells contain abnormally small, disorganized eyespots in which the chloroplast envelope and plasma membrane are no longer apposed. The MIN1 gene, identified here by phenotypic rescue, encodes a protein with an N-terminal C2 domain and a C-terminal LysM domain separated by a transmembrane sequence. This novel domain architecture led to the hypothesis that MIN1 is in the plasma membrane or the chloroplast envelope, where membrane association of the C2 domain promotes proper eyespot organization. Mutation of conserved C2 domain loop residues disrupted association of the MIN1 C2 domain with the chloroplast envelope in moss cells but did not abolish eyespot assembly in Chlamydomonas. In min1 null cells, channelrhodopsin-1 (ChR1) photoreceptor levels were reduced, indicating a role for MIN1 in ChR1 expression and/or stability. However, ChR1 localization was only minimally disturbed during photoautotrophic growth of min1 cells, conditions under which the pigment granule layers are disorganized. The data are consistent with the hypothesis that neither MIN1 nor proper organization of the plastidic components of the eyespot is essential for localization of ChR1.
Collapse
|
25
|
Merchant SS, Prochnik SE, Vallon O, Harris EH, Karpowicz SJ, Witman GB, Terry A, Salamov A, Fritz-Laylin LK, Maréchal-Drouard L, Marshall WF, Qu LH, Nelson DR, Sanderfoot AA, Spalding MH, Kapitonov VV, Ren Q, Ferris P, Lindquist E, Shapiro H, Lucas SM, Grimwood J, Schmutz J, Cardol P, Cerutti H, Chanfreau G, Chen CL, Cognat V, Croft MT, Dent R, Dutcher S, Fernández E, Ferris P, Fukuzawa H, González-Ballester D, González-Halphen D, Hallmann A, Hanikenne M, Hippler M, Inwood W, Jabbari K, Kalanon M, Kuras R, Lefebvre PA, Lemaire SD, Lobanov AV, Lohr M, Manuell A, Meier I, Mets L, Mittag M, Mittelmeier T, Moroney JV, Moseley J, Napoli C, Nedelcu AM, Niyogi K, Novoselov SV, Paulsen IT, Pazour G, Purton S, Ral JP, Riaño-Pachón DM, Riekhof W, Rymarquis L, Schroda M, Stern D, Umen J, Willows R, Wilson N, Zimmer SL, Allmer J, Balk J, Bisova K, Chen CJ, Elias M, Gendler K, Hauser C, Lamb MR, Ledford H, Long JC, Minagawa J, Page MD, Pan J, Pootakham W, Roje S, Rose A, Stahlberg E, Terauchi AM, Yang P, Ball S, Bowler C, Dieckmann CL, Gladyshev VN, Green P, Jorgensen R, Mayfield S, Mueller-Roeber B, Rajamani S, Sayre RT, Brokstein P, Dubchak I, Goodstein D, Hornick L, Huang YW, Jhaveri J, Luo Y, Martínez D, Ngau WCA, Otillar B, Poliakov A, Porter A, Szajkowski L, Werner G, Zhou K, Grigoriev IV, Rokhsar DS, Grossman AR. The Chlamydomonas genome reveals the evolution of key animal and plant functions. Science 2007; 318:245-50. [PMID: 17932292 PMCID: PMC2875087 DOI: 10.1126/science.1143609] [Citation(s) in RCA: 1797] [Impact Index Per Article: 105.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Chlamydomonas reinhardtii is a unicellular green alga whose lineage diverged from land plants over 1 billion years ago. It is a model system for studying chloroplast-based photosynthesis, as well as the structure, assembly, and function of eukaryotic flagella (cilia), which were inherited from the common ancestor of plants and animals, but lost in land plants. We sequenced the approximately 120-megabase nuclear genome of Chlamydomonas and performed comparative phylogenomic analyses, identifying genes encoding uncharacterized proteins that are likely associated with the function and biogenesis of chloroplasts or eukaryotic flagella. Analyses of the Chlamydomonas genome advance our understanding of the ancestral eukaryotic cell, reveal previously unknown genes associated with photosynthetic and flagellar functions, and establish links between ciliopathy and the composition and function of flagella.
Collapse
Affiliation(s)
- Sabeeha S. Merchant
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Simon E. Prochnik
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Olivier Vallon
- CNRS, UMR 7141, CNRS/Université Paris 6, Institut de Biologie Physico-Chimique, 75005 Paris, France
| | | | - Steven J. Karpowicz
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - George B. Witman
- Department of Cell Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Astrid Terry
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Asaf Salamov
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Lillian K. Fritz-Laylin
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA94720, USA
| | | | - Wallace F. Marshall
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA 94143, USA
| | - Liang-Hu Qu
- Biotechnology Research Center, Zhongshan University, Guangzhou 510275, China
| | - David R. Nelson
- Department of Molecular Sciences and Center of Excellence in Genomics and Bioinformatics, University of Tennessee, Memphis, TN 38163, USA
| | - Anton A. Sanderfoot
- Department of Plant Biology, University of Minnesota, St. Paul MN 55108, USA
| | - Martin H. Spalding
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, IA 50011, USA
| | | | - Qinghu Ren
- The Institute for Genomic Research, Rockville, MD 20850, USA
| | - Patrick Ferris
- Plant Biology Laboratory, Salk Institute, La Jolla, CA 92037, USA
| | - Erika Lindquist
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Harris Shapiro
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Susan M. Lucas
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Jane Grimwood
- Stanford Human Genome Center, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Jeremy Schmutz
- Stanford Human Genome Center, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Pierre Cardol
- CNRS, UMR 7141, CNRS/Université Paris 6, Institut de Biologie Physico-Chimique, 75005 Paris, France
- Plant Biology Institute, Department of Life Sciences, University of Liège, B-4000 Liège, Belgium
| | - Heriberto Cerutti
- University of Nebraska-Lincoln, School of Biological Sciences–Plant Science Initiative, Lincoln, NE 68588, USA
| | - Guillaume Chanfreau
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Chun-Long Chen
- Biotechnology Research Center, Zhongshan University, Guangzhou 510275, China
| | - Valérie Cognat
- Institut de Biologie Moléculaire des Plantes, CNRS, 67084 Strasbourg Cedex, France
| | - Martin T. Croft
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK
| | - Rachel Dent
- Department of Plant and Microbial Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Susan Dutcher
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Emilio Fernández
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Córdoba, Campus de Rabanales, 14071 Córdoba, Spain
| | - Patrick Ferris
- Plant Biology Laboratory, Salk Institute, La Jolla, CA 92037, USA
| | - Hideya Fukuzawa
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | | | - Diego González-Halphen
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México 04510 DF, Mexico
| | - Armin Hallmann
- Department of Cellular and Developmental Biology of Plants, University of Bielefeld, D-33615 Bielefeld, Germany
| | - Marc Hanikenne
- Plant Biology Institute, Department of Life Sciences, University of Liège, B-4000 Liège, Belgium
| | - Michael Hippler
- Department of Biology, Institute of Plant Biochemistry and Biotechnology, University of Münster, 48143 Münster, Germany
| | - William Inwood
- Department of Plant and Microbial Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Kamel Jabbari
- CNRS UMR 8186, Département de Biologie, Ecole Normale Supérieure, 75230 Paris, France
| | - Ming Kalanon
- Plant Cell Biology Research Centre, The School of Botany, The University of Melbourne, Parkville, Melbourne, VIC 3010, Australia
| | - Richard Kuras
- CNRS, UMR 7141, CNRS/Université Paris 6, Institut de Biologie Physico-Chimique, 75005 Paris, France
| | - Paul A. Lefebvre
- Department of Plant Biology, University of Minnesota, St. Paul MN 55108, USA
| | - Stéphane D. Lemaire
- Institut de Biotechnologie des Plantes, UMR 8618, CNRS/Université Paris-Sud, Orsay, France
| | - Alexey V. Lobanov
- Department of Biochemistry, N151 Beadle Center, University of Nebraska, Lincoln, NE 68588–0664, USA
| | - Martin Lohr
- Institut für Allgemeine Botanik, Johannes Gutenberg-Universität, 55099 Mainz, Germany
| | - Andrea Manuell
- Department of Cell Biology and Skaggs Institute for Chemical Biology, Scripps Research Institute, La Jolla, CA 92037, USA
| | - Iris Meier
- PCMB and Plant Biotechnology Center, Ohio State University, Columbus, OH 43210, USA
| | - Laurens Mets
- Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Maria Mittag
- Institut für Allgemeine Botanik und Pflanzenphysiologie, Friedrich-Schiller-Universität Jena, 07743 Jena, Germany
| | - Telsa Mittelmeier
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721, USA
| | - James V. Moroney
- Department of Biological Science, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Jeffrey Moseley
- Department of Plant Biology, Carnegie Institution, Stanford, CA 94306, USA
| | - Carolyn Napoli
- Department of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Aurora M. Nedelcu
- Department of Biology, University of New Brunswick, Fredericton, NB, Canada E3B 6E1
| | - Krishna Niyogi
- Department of Plant and Microbial Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Sergey V. Novoselov
- Department of Biochemistry, N151 Beadle Center, University of Nebraska, Lincoln, NE 68588–0664, USA
| | - Ian T. Paulsen
- The Institute for Genomic Research, Rockville, MD 20850, USA
| | - Greg Pazour
- Department of Physiology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Saul Purton
- Department of Biology, University College London, London WC1E 6BT, UK
| | - Jean-Philippe Ral
- Unité de Glycobiologie Structurale et Fonctionnelle, UMR8576 CNRS/USTL, IFR 118, Université des Sciences et Technologies de Lille, Cedex, France
| | | | - Wayne Riekhof
- Department of Medicine, National Jewish Medical and Research Center, Denver, CO 80206, USA
| | - Linda Rymarquis
- Delaware Biotechnology Institute, University of Delaware, Newark, DE 19711, USA
| | - Michael Schroda
- Institute of Biology II/Plant Biochemistry, 79104 Freiburg, Germany
| | - David Stern
- Boyce Thompson Institute for Plant Research at Cornell University, Ithaca, NY 14853, USA
| | - James Umen
- Plant Biology Laboratory, Salk Institute, La Jolla, CA 92037, USA
| | - Robert Willows
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney 2109, Australia
| | - Nedra Wilson
- Department of Anatomy and Cell Biology, Oklahoma State University, Center for Health Sciences, Tulsa, OK 74107, USA
| | - Sara Lana Zimmer
- Boyce Thompson Institute for Plant Research at Cornell University, Ithaca, NY 14853, USA
| | - Jens Allmer
- Izmir Ekonomi Universitesi, 35330 Balcova-Izmir Turkey
| | - Janneke Balk
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK
| | - Katerina Bisova
- Institute of Microbiology, Czech Academy of Sciences, Czech Republic
| | - Chong-Jian Chen
- Biotechnology Research Center, Zhongshan University, Guangzhou 510275, China
| | - Marek Elias
- Department of Plant Physiology, Faculty of Sciences, Charles University, 128 44 Prague 2, Czech Republic
| | - Karla Gendler
- Department of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Charles Hauser
- Bioinformatics Program, St. Edward's University, Austin, TX 78704, USA
| | - Mary Rose Lamb
- Department of Biology, University of Puget Sound, Tacoma, WA 98407, USA
| | - Heidi Ledford
- Department of Plant and Microbial Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Joanne C. Long
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Jun Minagawa
- Institute of Low-Temperature Science, Hokkaido University, 060-0819, Japan
| | - M. Dudley Page
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Junmin Pan
- Department of Biology, Tsinghua University, Beijing, China 100084
| | - Wirulda Pootakham
- Department of Plant Biology, Carnegie Institution, Stanford, CA 94306, USA
| | - Sanja Roje
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA
| | | | - Eric Stahlberg
- PCMB and Plant Biotechnology Center, Ohio State University, Columbus, OH 43210, USA
| | - Aimee M. Terauchi
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Pinfen Yang
- Department of Biology, Marquette University, Milwaukee, WI 53233, USA
| | - Steven Ball
- UMR8576 CNRS, Laboratory of Biological Chemistry, 59655 Villeneuve d'Ascq, France
| | - Chris Bowler
- CNRS UMR 8186, Département de Biologie, Ecole Normale Supérieure, 75230 Paris, France
- Cell Signaling Laboratory, Stazione Zoologica, I 80121 Naples, Italy
| | - Carol L. Dieckmann
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721, USA
| | - Vadim N. Gladyshev
- Department of Biochemistry, N151 Beadle Center, University of Nebraska, Lincoln, NE 68588–0664, USA
| | - Pamela Green
- Delaware Biotechnology Institute, University of Delaware, Newark, DE 19711, USA
| | - Richard Jorgensen
- Department of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Stephen Mayfield
- Department of Cell Biology and Skaggs Institute for Chemical Biology, Scripps Research Institute, La Jolla, CA 92037, USA
| | | | - Sathish Rajamani
- Graduate Program in Biophysics, Ohio State University, Columbus, OH 43210, USA
| | - Richard T. Sayre
- PCMB and Plant Biotechnology Center, Ohio State University, Columbus, OH 43210, USA
| | - Peter Brokstein
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Inna Dubchak
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - David Goodstein
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Leila Hornick
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Y. Wayne Huang
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Jinal Jhaveri
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Yigong Luo
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Diego Martínez
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Wing Chi Abby Ngau
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Bobby Otillar
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Alexander Poliakov
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Aaron Porter
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Lukasz Szajkowski
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Gregory Werner
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Kemin Zhou
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Igor V. Grigoriev
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Daniel S. Rokhsar
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA94720, USA
| | - Arthur R. Grossman
- Department of Plant Biology, Carnegie Institution, Stanford, CA 94306, USA
| |
Collapse
|
26
|
Merchant SS, Prochnik SE, Vallon O, Harris EH, Karpowicz SJ, Witman GB, Terry A, Salamov A, Fritz-Laylin LK, Maréchal-Drouard L, Marshall WF, Qu LH, Nelson DR, Sanderfoot AA, Spalding MH, Kapitonov VV, Ren Q, Ferris P, Lindquist E, Shapiro H, Lucas SM, Grimwood J, Schmutz J, Cardol P, Cerutti H, Chanfreau G, Chen CL, Cognat V, Croft MT, Dent R, Dutcher S, Fernández E, Fukuzawa H, González-Ballester D, González-Halphen D, Hallmann A, Hanikenne M, Hippler M, Inwood W, Jabbari K, Kalanon M, Kuras R, Lefebvre PA, Lemaire SD, Lobanov AV, Lohr M, Manuell A, Meier I, Mets L, Mittag M, Mittelmeier T, Moroney JV, Moseley J, Napoli C, Nedelcu AM, Niyogi K, Novoselov SV, Paulsen IT, Pazour G, Purton S, Ral JP, Riaño-Pachón DM, Riekhof W, Rymarquis L, Schroda M, Stern D, Umen J, Willows R, Wilson N, Zimmer SL, Allmer J, Balk J, Bisova K, Chen CJ, Elias M, Gendler K, Hauser C, Lamb MR, Ledford H, Long JC, Minagawa J, Page MD, Pan J, Pootakham W, Roje S, Rose A, Stahlberg E, Terauchi AM, Yang P, Ball S, Bowler C, Dieckmann CL, Gladyshev VN, Green P, Jorgensen R, Mayfield S, Mueller-Roeber B, Rajamani S, Sayre RT, Brokstein P, Dubchak I, Goodstein D, Hornick L, Huang YW, Jhaveri J, Luo Y, Martínez D, Ngau WCA, Otillar B, Poliakov A, Porter A, Szajkowski L, Werner G, Zhou K, Grigoriev IV, Rokhsar DS, Grossman AR. The Chlamydomonas genome reveals the evolution of key animal and plant functions. Science 2007. [PMID: 17932292 DOI: 10.1126/science.1143609.the] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Chlamydomonas reinhardtii is a unicellular green alga whose lineage diverged from land plants over 1 billion years ago. It is a model system for studying chloroplast-based photosynthesis, as well as the structure, assembly, and function of eukaryotic flagella (cilia), which were inherited from the common ancestor of plants and animals, but lost in land plants. We sequenced the approximately 120-megabase nuclear genome of Chlamydomonas and performed comparative phylogenomic analyses, identifying genes encoding uncharacterized proteins that are likely associated with the function and biogenesis of chloroplasts or eukaryotic flagella. Analyses of the Chlamydomonas genome advance our understanding of the ancestral eukaryotic cell, reveal previously unknown genes associated with photosynthetic and flagellar functions, and establish links between ciliopathy and the composition and function of flagella.
Collapse
Affiliation(s)
- Sabeeha S Merchant
- Department of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Yu CTR, Li JH, Lee TC, Lin LF. Characterization of cocaine-elicited cell vacuolation: the involvement of calcium/calmodulin in organelle deregulation. J Biomed Sci 2007; 15:215-26. [PMID: 17922255 DOI: 10.1007/s11373-007-9213-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2007] [Accepted: 09/13/2007] [Indexed: 11/30/2022] Open
Abstract
The sizes of organelles are tightly regulated in the cells. However, little is known on how cells maintain the homeostasis of these intracellular compartments. Using cocaine as a model compound, we have characterized the mechanism of deregulated vacuolation in cultured rat liver epithelial Clone 9 cells. The vacuoles were observed as early as 10 min following cocaine treatment. Removal of cocaine led to vacuole degeneration, indicating vacuolation is a reversible process. The vacuoles could devour intracellular materials and the vacuoles originated from late endosome/lysosome as indicated by immunofluorescence studies. Instant calcium influx and calmodulin were required for the initiation of vacuole formation. The unique properties of these late endosome/lysosome-derived vacuoles were further discussed. In summary, cocaine elicited a new type of deregulated vacuole and the involvement of calcium/calmodulin in vacuolation could shed light on prevention or treatment of cocaine-induced cytotoxicity.
Collapse
Affiliation(s)
- Chang-Tze R Yu
- Graduate Institute of Biomedicine and Biomedical Technology, National Chi Nan University, Puli, Nantou, 545, Taiwan, ROC
| | | | | | | |
Collapse
|
28
|
Schmidt M, Gessner G, Luff M, Heiland I, Wagner V, Kaminski M, Geimer S, Eitzinger N, Reissenweber T, Voytsekh O, Fiedler M, Mittag M, Kreimer G. Proteomic analysis of the eyespot of Chlamydomonas reinhardtii provides novel insights into its components and tactic movements. THE PLANT CELL 2006; 18:1908-30. [PMID: 16798888 PMCID: PMC1533972 DOI: 10.1105/tpc.106.041749] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Flagellate green algae have developed a visual system, the eyespot apparatus, which allows the cell to phototax. To further understand the molecular organization of the eyespot apparatus and the phototactic movement that is controlled by light and the circadian clock, a detailed understanding of all components of the eyespot apparatus is needed. We developed a procedure to purify the eyespot apparatus from the green model alga Chlamydomonas reinhardtii. Its proteomic analysis resulted in the identification of 202 different proteins with at least two different peptides (984 in total). These data provide new insights into structural components of the eyespot apparatus, photoreceptors, retina(l)-related proteins, members of putative signaling pathways for phototaxis and chemotaxis, and metabolic pathways within an algal visual system. In addition, we have performed a functional analysis of one of the identified putative components of the phototactic signaling pathway, casein kinase 1 (CK1). CK1 is also present in the flagella and thus is a promising candidate for controlling behavioral responses to light. We demonstrate that silencing CK1 by RNA interference reduces its level in both flagella and eyespot. In addition, we show that silencing of CK1 results in severe disturbances in hatching, flagellum formation, and circadian control of phototaxis.
Collapse
Affiliation(s)
- Melanie Schmidt
- Institute of Biology, Friedrich-Alexander-University, D-91058 Erlangen, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Abstract
The eyespot organelle of the green alga Chlamydomonas allows the cell to phototax toward (or away) from light to maximize the light intensity for photosynthesis and minimize photo-damage. At cytokinesis, the eyespot is resorbed at the cleavage furrow and two new eyespots form in the daughter cells 180 degrees from each other. The eyespots are positioned asymmetrically with respect to the microtubule cytoskeleton. Eyespots are assembled from all three chloroplast membranes and carotenoid-filled granules, which form a sandwich structure overlaid by the tightly apposed plasma membrane. This review describes (1) my interest in cellular asymmetry and organelle biology, (2) isolation of mutations that describe four genes governing eyespot placement and assembly, (3) the characterization of the EYE2 gene, which encodes a thioredoxin superfamily member, and (4) the characterization of the MIN1 gene, which is required for the layered organization of granules and membranes in the eyespot. BioEssays 25:410-416, 2003.
Collapse
Affiliation(s)
- Carol L Dieckmann
- Department of Biochemistry and Molecular Biophysics, University of Arizona, P. O. Box 210106, Tucson, AZ 85721-0106, USA.
| |
Collapse
|
30
|
Abstract
The mechanisms that control organelle size are unknown. Flagellar length regulation is the most accessible of all organelle-size-control problems, and experiments on flagellar assembly have provided important clues to how flagellar length is controlled, as a balance of assembly and disassembly. I propose that the inherent length dependence of intraflagellar transport might be what allows the flagellum to reach a defined length. This model of the flagellum might represent a general scheme for organelle size control that could apply to any organelle whose maintenance involves continuous assembly balanced by disassembly.
Collapse
Affiliation(s)
- Wallace Marshall
- Dept Molecular, Cellular and Developmental Biology, Yale University, 266 Whitney Ave, New Haven, CT, USA.
| |
Collapse
|
31
|
Roberts DG, Lamb MR, Dieckmann CL. Characterization of the EYE2 gene required for eyespot assembly in Chlamydomonas reinhardtii. Genetics 2001; 158:1037-49. [PMID: 11454753 PMCID: PMC1461727 DOI: 10.1093/genetics/158.3.1037] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The unicellular biflagellate green alga Chlamydomonas reinhardtii can perceive light and respond by altering its swimming behavior. The eyespot is a specialized structure for sensing light, which is assembled de novo at every cell division from components located in two different cellular compartments. Photoreceptors and associated signal transduction components are localized in a discrete patch of the plasma membrane. This patch is tightly packed against an underlying sandwich of chloroplast membranes and carotenoid-filled lipid granules, which aids the cell in distinguishing light direction. In a prior screen for mutant strains with eyespot defects, the EYE2 locus was defined by the single eye2-1 allele. The mutant strain has no eyespot by light microscopy and has no organized carotenoid granule layers as judged by electron microscopy. Here we demonstrate that the eye2-1 mutant is capable of responding to light, although the strain is far less sensitive than wild type to low light intensities and orients imprecisely. Therefore, pigment granule layer assembly in the chloroplast is not required for photoreceptor localization in the plasma membrane. A plasmid-insertion mutagenesis screen yielded the eye2-2 allele, which allowed the isolation and characterization of the EYE2 gene. The EYE2 protein is a member of the thioredoxin superfamily. Site-directed mutagenesis of the active site cysteines demonstrated that EYE2 function in eyespot assembly is redox independent, similar to the auxiliary functions of other thioredoxin family members in protein folding and complex assembly.
Collapse
Affiliation(s)
- D G Roberts
- Department of Biochemistry, University of Arizona, Tucson, Arizona 85721, USA
| | | | | |
Collapse
|
32
|
Harris EH. CHLAMYDOMONAS AS A MODEL ORGANISM. ANNUAL REVIEW OF PLANT PHYSIOLOGY AND PLANT MOLECULAR BIOLOGY 2001; 52:363-406. [PMID: 11337403 DOI: 10.1146/annurev.arplant.52.1.363] [Citation(s) in RCA: 427] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The unicellular green alga Chlamydomonas offers a simple life cycle, easy isolation of mutants, and a growing array of tools and techniques for molecular genetic studies. Among the principal areas of current investigation using this model system are flagellar structure and function, genetics of basal bodies (centrioles), chloroplast biogenesis, photosynthesis, light perception, cell-cell recognition, and cell cycle control. A genome project has begun with compilation of expressed sequence tag data and gene expression studies and will lead to a complete genome sequence. Resources available to the research community include wild-type and mutant strains, plasmid constructs for transformation studies, and a comprehensive on-line database.
Collapse
Affiliation(s)
- Elizabeth H Harris
- Developmental, Cell and Molecular Biology Group, Biology Department, Duke University, Durham, North Carolina 27708-1000; e-mail:
| |
Collapse
|