scholarly journals The Cytochrome c Gene from the Green Alga Chlamydomonas reinhardtii. Structure and Expression in Wild-Type Cells and in Obligate Photoautotrophic (dk) Mutants

2000 ◽  
Vol 41 (10) ◽  
pp. 1149-1156 ◽  
Author(s):  
Silvina A. Felitti ◽  
Raquel L. Chan ◽  
Manuel González Sierra ◽  
Daniel H. Gonzalez
Keyword(s):  
Cytochrome C ◽  
Chlamydomonas Reinhardtii ◽  
Green Alga ◽  
Wild Type

Identification of genes required for hydrogenase activity in Chlamydomonas reinhardtii

2005 ◽  
Vol 33 (1) ◽  
pp. 102-104 ◽  
Author(s):  
M.C. Posewitz ◽  
P.W. King ◽  
S.L. Smolinski ◽  
R. Davis Smith ◽  
A.R. Ginley ◽  
...  
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Green Alga ◽  
Transcriptional Response ◽  
H2 Production ◽  
Hydrogenase Activity ◽  
Wild Type ◽  
Anaerobic Conditions ◽  
H2 Photoproduction ◽  
H2 Sensor

The eukaryotic green alga, Chlamydomonas reinhardtii, produces H2 under anaerobic conditions, in a reaction catalysed by an [FeFe]-hydrogenase. To identify genes that influence H2 production in C. reinhardtii, a library of 6000 colonies on agar plates was screened with sensitive chemochromic H2-sensor films for clones defective in H2 production. Two mutants of particular interest were fully characterized. One mutant, hydEF-1, is unable to assemble an active [FeFe]-hydrogenase. This is the first reported C. reinhardtii mutant that is not capable of producing any H2. The second mutant, sta7-10, is not able to accumulate insoluble starch and has significantly lowered H2-photoproduction rates in comparison with the wild-type. In hydEF-1, anaerobiosis induces transcription of the two reported C. reinhardtii hydrogenase genes, HydA1 and HydA2, indicating a normal transcriptional response to anaerobiosis. In contrast, the transcription of both hydrogenase genes in sta7-10 is significantly attenuated.

RNA silencing of hydrogenase(-like) genes and investigation of their physiological roles in the green alga Chlamydomonas reinhardtii

2010 ◽  
Vol 431 (3) ◽  
pp. 345-352 ◽  
Author(s):  
James E. Godman ◽  
Attila Molnár ◽  
David C. Baulcombe ◽  
Janneke Balk
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Green Alga ◽  
Rna Silencing ◽  
Aldehyde Oxidase ◽  
Eukaryotic Cell ◽  
Unique Combination ◽  
Wild Type ◽  
Anaerobic Conditions ◽  
Production Cell

The genome of the green alga Chlamydomonas reinhardtii encodes two [FeFe]-hydrogenases, HydA1 and HydA2, and the hydrogenase-like protein HYD3. The unique combination of these proteins in one eukaryotic cell allows for direct comparison of their in vivo functions, which have not been established for HydA2 and HYD3. Using an artificial microRNA silencing method developed recently, the expression of HydA1, HydA2 and HYD3 was specifically down-regulated. Silencing of HydA1 resulted in 4-fold lower hydrogenase protein and activity under anaerobic conditions. In contrast, silencing of HydA2 or HYD3 did not affect hydrogen production. Cell lines with strongly (>90%) decreased HYD3 transcript levels grew more slowly than wild-type. The activity of aldehyde oxidase, a cytosolic Fe-S enzyme, was decreased in HYD3-knockdown lines, whereas Fe-S dependent activities in the chloroplast and mitochondria were unaffected. In addition, the HYD3-knockdown lines grew poorly on hypoxanthine, indicating impaired function of xanthine dehydrogenase, another cytosolic Fe-S enzyme. The expression levels of selected genes in response to hypoxia were unaltered upon HYD3 silencing. Together, our results clearly distinguish the cellular roles of HydA1 and HYD3, and indicate that HYD3, like its yeast and human homologues, has an evolutionary conserved role in the biogenesis or maintenance of cytosolic Fe-S proteins.

scholarly journals Induction and characterization of mitochondrial DNA mutants in Chlamydomonas reinhardtii.

1989 ◽  
Vol 108 (4) ◽  
pp. 1221-1226 ◽  
Author(s):  
R F Matagne ◽  
M R Michel-Wolwertz ◽  
C Munaut ◽  
C Duyckaerts ◽  
F Sluse
Keyword(s):  
Mitochondrial Dna ◽  
Cytochrome C ◽  
Chlamydomonas Reinhardtii ◽  
Cytochrome C Oxidase ◽  
Oxidase Activity ◽  
Wild Type ◽  
Apocytochrome B ◽  
Cytochrome Pathway ◽  
Apocytochrome B Gene

In addition to lethal minute colony mutations which correspond to loss of mitochondrial DNA, acriflavin induces in Chlamydomonas reinhardtii a low percentage of cells that grow in the light but do not divide under heterotrophic conditions. Two such obligate photoautotrophic mutants were shown to lack the cyanide-sensitive cytochrome pathway of the respiration and to have a reduced cytochrome c oxidase activity. In crosses to wild type, the mutations are transmitted almost exclusively from the mating type minus parent. A same pattern of inheritance is seen for the mitochondrial DNA in crosses between the two interfertile species C. reinhardtii and Chlamydomonas smithii. Both mutants have a deletion in the region of the mitochondrial DNA containing the apocytochrome b gene and possibly the unidentified URFx gene.

scholarly journals Asymmetric properties of the Chlamydomonas reinhardtii cytoskeleton direct rhodopsin photoreceptor localization

2011 ◽  
Vol 193 (4) ◽  
pp. 741-753 ◽  
Author(s):  
Telsa M. Mittelmeier ◽  
Joseph S. Boyd ◽  
Mary Rose Lamb ◽  
Carol L. Dieckmann
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Green Alga ◽  
Basal Body ◽  
Cytoskeletal Protein ◽  
Wild Type ◽  
Unicellular Green Alga ◽  
Protein Mutations ◽  
The Relationship ◽  
Mutant Cells ◽  
In Cells

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.

Knock-down of the COX3 and COX17 gene expression of cytochrome c oxidase in the unicellular green alga Chlamydomonas reinhardtii

2010 ◽  
Vol 74 (3) ◽  
pp. 223-233 ◽  
Author(s):  
Claire Remacle ◽  
Nadine Coosemans ◽  
Frédéric Jans ◽  
Marc Hanikenne ◽  
Patrick Motte ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cytochrome C ◽  
Chlamydomonas Reinhardtii ◽  
Cytochrome C Oxidase ◽  
Green Alga ◽  
Knock Down ◽  
Unicellular Green Alga ◽  
Cox17 Gene
Sign in / Sign up

Export Citation Format

Share Document