scholarly journals Genetic Analysis of Flagellar Length Control in Chlamydomonas reinhardtii: A New Long-Flagella Locus and Extragenic Suppressor Mutations

Genetics ◽  
1998 ◽  
Vol 148 (2) ◽  
pp. 693-702
Author(s):  
Catherine M Asleson ◽  
Paul A Lefebvre
Keyword(s):  
Genetic Analysis ◽  
Chlamydomonas Reinhardtii ◽  
Double Mutant ◽  
Wild Type ◽  
Suppressor Mutations ◽  
Extragenic Suppressor ◽  
Flagellar Regeneration

Abstract Flagellar length in the biflagellate alga Chlamydomonas reinhardtii is under constant and tight regulation. A number of mutants with defects in flagellar length control have been previously identified. Mutations in the three long-flagella (lf) loci result in flagella that are up to three times longer than wild-type length. In this article, we describe the isolation of long-flagellar mutants caused by mutations in a new LF locus, LF4. lf4 mutations were shown to be epistatic to lf1, while lf2 was found to be epistatic to lf4 with regard to the flagellar regeneration defect. Mutations in lf4 were able to suppress the synthetic flagella-less phenotype of the lf1, lf2 double mutant. In addition, we have isolated four extragenic suppressor mutations that suppress the long-flagella phenotype of lf1, lf2, or lf3 double mutants.

Abscisic acid resistant mutants in the fern Ceratopteris: characterization and genetic analysis

1985 ◽  
Vol 63 (9) ◽  
pp. 1582-1585 ◽  
Author(s):  
Leslie G. Hickok
Keyword(s):  
Abscisic Acid ◽  
Genetic Analysis ◽  
Sexual Differentiation ◽  
Double Mutant ◽  
Acid Resistance ◽  
The Other ◽  
Additive Effects ◽  
Wild Type ◽  
Resistant Mutants ◽  
Moderate Resistance

Abscisic acid normally inhibits growth and male sexual differentiation (antheridia formation) in gametophytes of the fern Ceratopteris. Abscisic acid resistant mutants show increased growth and sexual differentiation in comparison with the wild type when cultured in the presence of abscisic acid. Two different mutants that confer resistance to the effects of abscisic acid have been fully characterized. One shows moderate resistance and the other strong resistance. The mutations involve separate but linked loci. Recombination between the loci yields double mutant (cis) recombinants that exhibit additive effects and show exceptional levels of abscisic acid resistance.

scholarly journals Genetic analysis of the phosphatases in Aspergillus nidulans

1965 ◽  
Vol 6 (1) ◽  
pp. 13-26 ◽  
Author(s):  
G. Dorn
Keyword(s):  
Alkaline Phosphatase ◽  
Acid Phosphatase ◽  
Genetic Analysis ◽  
Aspergillus Nidulans ◽  
Alkaline Ph ◽  
Wild Type ◽  
Linkage Groups ◽  
Partial Restoration ◽  
Suppressor Mutations ◽  
Alkaline And Acid Phosphatase

Summary1. A histochemical method has been applied to the detection of alkaline and acid phosphatase mutants in single colonies of Aspergillus nidulans.2. With the above method it has been possible to isolate mutants in which the alkaline and acid phosphatase activities are affected either separately or simultaneously.3. Crude extracts of wild-type A. nidulans contain four electrophoretically distinct phosphatase components, two with activity at alkaline pH and two with activity at acid pH. Genes affecting three of the four components have been identified.4. Two suppressor mutants of an alkaline phosphataseless mutant (palB7) have been isolated. In a strain carrying palB7 and one of these suppressors, the restoration of an alkaline phosphatase component is accompanied by loss of the faster acid phosphatase component. In a similar strain carrying the other suppressor, the partial restoration of the alkaline phosphatase component goes with an electrophoretic alteration of the slower acid phosphatase component.5. Genetic analysis of twenty-seven mutants has resulted in the identification of fifteen loci affecting the phosphatases. All these loci have been assigned to linkage groups, and twelve of them were also mapped meiotically in relation to other loci.6. One possible model (based on heteropolymeric proteins) has been proposed to account for the electrophoretic and genetic data on the various phosphatase and suppressor mutations.

scholarly journals Chlamydomonas reinhardtii CNX1E Reconstitutes Molybdenum Cofactor Biosynthesis in Escherichia coli Mutants

2007 ◽  
Vol 6 (6) ◽  
pp. 1063-1067 ◽  
Author(s):  
Ángel Llamas ◽  
Manuel Tejada-Jimenez ◽  
David González-Ballester ◽  
José Javier Higuera ◽  
Guenter Schwarz ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Chlamydomonas Reinhardtii ◽  
Double Mutant ◽  
Molybdenum Cofactor ◽  
Wild Type ◽  
Eukaryotic Protein ◽  
E Coli ◽  
Wild Type Phenotype ◽  
Cofactor Biosynthesis ◽  
Molybdenum Cofactor Biosynthesis

ABSTRACT We have isolated and characterized the Chlamydomonas reinhardtii genes for molybdenum cofactor biosynthesis, namely, CNX1G and CNX1E, and expressed them and their chimeric fusions in Chlamydomonas and Escherichia coli. In all cases, the wild-type phenotype was restored in individual mutants as well as in a CNX1G CNX1E double mutant. Therefore, CrCNX1E is the first eukaryotic protein able to complement an E. coli moeA mutant.

scholarly journals Two types of Chlamydomonas flagellar mutants missing different components of inner-arm dynein.

1991 ◽  
Vol 112 (3) ◽  
pp. 441-447 ◽  
Author(s):  
R Kamiya ◽  
E Kurimoto ◽  
E Muto
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Cross Section ◽  
Double Mutant ◽  
The Other ◽  
Flagellar Motility ◽  
Wild Type ◽  
Single Group ◽  
Heavy Chains ◽  
Section Electron ◽  
Dynein Arms

Two types of Chlamydomonas reinhardtii flagellar mutants (idaA and idaB) lacking partial components of the inner-arm dynein were isolated by screening mutations that produce paralyzed phenotypes when present in a mutant missing outer-arm dynein. Of the currently identified three inner-arm subspecies I1, I2, and I3, each containing two heterologous heavy chains (Piperno, G., Z. Ramanis, E. F. Smith, and W. S. Sale. 1990. J. Cell Biol. 110:379-389), idaA and idaB lacked I1 and I2, respectively. The 13 idA isolates comprised three genetically different groups (ida1, ida2, ida3) and the two idaB isolates comprised a single group (ida4). In averaged cross-section electron micrographs, inner dynein arms in wild-type axonemes appeared to have two projections pointing to discrete directions. In ida1-3 and ida4 axonemes, on the other hand, either one of them was missing or greatly diminished. Both projections were weak in the double mutant ida1-3 x ida4. These observations suggest that the inner dynein arms in Chlamydomonas axonemes are aligned not in a single straight row, but in a staggered row or two discrete rows. Both ida1-3 and ida4 swam at reduced speed. Thus, the inner-arm subspecies missing in these mutants are not necessary for flagellar motility. However, the double mutants ida1-3 x ida4 were nonmotile, suggesting that axonemes with significant defects in inner arms cannot function. The inner-arm dynein should be important for the generation of axonemal beating.

scholarly journals Genetic analysis of long-flagella mutants of Chlamydomonas reinhardtii.

Genetics ◽  
1988 ◽  
Vol 118 (4) ◽  
pp. 637-648
Author(s):  
S E Barsel ◽  
D E Wexler ◽  
P A Lefebvre
Keyword(s):  
Linkage Group ◽  
Genetic Analysis ◽  
Chlamydomonas Reinhardtii ◽  
Wild Type ◽  
Group I ◽  
New Gene ◽  
Complementation Groups ◽  
Rapid Regeneration ◽  
Time Required

Abstract The length of the flagella of Chlamydomonas reinhardtii cells is tightly regulated; both short-flagella and long-flagella mutants have been described. This report characterizes ten long-flagella mutants, including five newly isolated mutants, to determine the number of different loci conferring this phenotype, and to study interactions of mutants at different loci. The mutants, each of which was recessive in heterozygous diploids with wild type, fall into three unlinked complementation groups. One of these defines a new gene, lf3, which maps near the centromere of linkage group I. The flagellar length distributions in populations of each mutant were broad, with the longest flagella measuring four times the length of the longest flagella seen on wild-type cells. Each of the ten mutants had defective flagellar regrowth after amputation. Some of the mutants showed no regrowth within the time required for wild-type cells to regenerate flagella completely. Other mutants had subpopulations with rapid regeneration kinetics, and subpopulations with no observable regeneration. The mutants were each crossed to wild type to form temporary quadriflagellate, dikaryon cells; in each case the long flagella were rapidly shortened in the presence of the wild-type cytoplasm, demonstrating that the mutants were recessive, and that length control could be exerted on already assembled flagella.

scholarly journals cdc2 and the regulation of mitosis: six interacting mcs genes.

Genetics ◽  
1989 ◽  
Vol 122 (4) ◽  
pp. 773-782 ◽  
Author(s):  
L Molz ◽  
R Booher ◽  
P Young ◽  
D Beach
Keyword(s):  
Protein Kinase ◽  
Double Mutant ◽  
Mitotic Catastrophe ◽  
Temperature Sensitive ◽  
Loss Of Function ◽  
Wild Type ◽  
Diverse Range ◽  
Lethal Phenotype ◽  
Suppressor Mutations ◽  
A Cell

Abstract A cdc2-3w weel-50 double mutant of fission yeast displays a temperature-sensitive lethal phenotype that is associated with gross abnormalities of chromosome segregation and has been termed mitotic catastrophe. In order to identify new genetic elements that might interact with the cdc2 protein kinase in the regulation of mitosis, we have isolated revertants of the lethal double mutant. The suppressor mutations define six mcs genes (mcs: mitotic catastrophe suppressor) that are not allelic to any of the following mitotic control genes: cdc2, wee 1, cdc13, cdc25, suc1 or nim1. Each mcs mutation is recessive with respect to wild-type in its ability to suppress mitotic catastrophe. None confer a lethal phenotype as a single mutant but few of the mutants are expected to be nulls. A diverse range of genetic interactions between the mcs mutants and other mitotic regulators were uncovered, including the following examples. First, mcs2 cdc2w or mcs6 cdc2w double mutants display a cell cycle defect dependent on the specific wee allele of cdc2. Second, both mcs1 cdc25-22 or mcs4 cdc25-22 double mutants are nonconditionally lethal, even at a temperature normally permissive for cdc25-22. Finally, the characteristic suppression of the cdc25 phenotype by a loss-of-function wee1 mutation is reversed in a mcs3 mutant background. The mcs genes define new mitotic elements that might be activators or substrates of the cdc2 protein kinase.

scholarly journals ADENOSINE 3',5'-CYCLIC MONOPHOSPHATE IN CHLAMYDOMONAS REINHARDTII

1973 ◽  
Vol 56 (3) ◽  
pp. 628-635 ◽  
Author(s):  
Robert W. Rubin ◽  
Philip Filner
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Camp Level ◽  
Cell Multiplication ◽  
Wild Type ◽  
Dibutyryl Camp ◽  
Cyclic Monophosphate ◽  
Synergistic Inhibition ◽  
Tenfold Increase ◽  
Microtubule Protein ◽  
Flagellar Regeneration

Adenosine 3',5'-cyclic monophosphate (cAMP) influences both flagellar function and flagellar regeneration in Chlamydomonas reinhardtii. The methylxanthine, aminophylline, which can cause a tenfold increase in cAMP level in C. reinhardtii, inhibits flagellar movement and flagellar regeneration by wild-type cells, without inhibiting cell multiplication. Caffeine, a closely related inhibitor, also inhibits flagellar movement and regeneration, but it inhibits cell multiplication too. Regeneration by a mutant lacking the central pair of flagellar microtubules was found to be more sensitive than wild type to inhibition by caffeine and to be subject to synergistic inhibition by aminophylline plus dibutyryl cAMP. Regeneration by three out of seven mutants with different flagellar abnormalities was more sensitive than wild type to these inhibitors. We interpret these results to mean that cAMP affects a component of the flagellum directly or indirectly, and that the responsiveness of that component to cAMP is enhanced by mutations which affect the integrity of the flagellum. The component in question could be microtubule protein.

scholarly journals Genetic analysis of the bacterial hook-capping protein FlgD responsible for hook assembly

Microbiology ◽  
2011 ◽  
Vol 157 (5) ◽  
pp. 1354-1362 ◽  
Author(s):  
Nao Moriya ◽  
Tohru Minamino ◽  
Katsumi Imada ◽  
Keiichi Namba
Keyword(s):  
Genetic Analysis ◽  
Salmonella Enterica ◽  
Culture Medium ◽  
Small Degree ◽  
Terminal Region ◽  
Wild Type ◽  
Capping Protein ◽  
Suppressor Mutations ◽  
Truncated Variants

FlgD of Salmonella enterica is a 232 aa protein that acts as the hook cap to promote assembly of FlgE into the hook structure. The N-terminal 86 residues (FlgDN) complement flgD mutants, albeit to a small degree. However, little is known about the role of the C-terminal region of FlgD (FlgDC). Here we isolated pseudorevertants from Salmonella flgE mutants. About half of the extragenic mutations lay within FlgDC and only one in FlgDN. These suppressor mutations prevented mutant FlgE subunits from leaking out to some degree. Two weakly motile flgD mutants encoding C-terminally truncated variants, FlgD(1-195) and FlgD(1-138f-s+4aa), secreted larger amounts of FlgE into the culture medium than wild-type cells. Their hooks were shorter, and their length distributions were broader, with significant tailing towards smaller values. These results suggest that FlgDC contributes to efficient hook polymerization. Therefore, we propose that FlgDN attaches to the distal end of the hook to promote hook polymerization and that FlgDC blocks the exit of newly exported FlgE monomers into the culture medium, allowing FlgE to have more time to assemble into the hook.

scholarly journals Functional expression of a yeast mitochondrial intron-encoded protein requires RNA processing at a conserved dodecamer sequence at the 3' end of the gene.

1989 ◽  
Vol 9 (4) ◽  
pp. 1507-1512 ◽  
Author(s):  
H Zhu ◽  
H Conrad-Webb ◽  
X S Liao ◽  
P S Perlman ◽  
R A Butow
Keyword(s):  
Genetic Analysis ◽  
Rna Processing ◽  
Fold Increase ◽  
Functional Expression ◽  
Rrna Gene ◽  
Yeast Mitochondria ◽  
Wild Type ◽  
Site Specific ◽  
Var1 Gene ◽  
A Site

All mRNAs of yeast mitochondria are processed at their 3' ends within a conserved dodecamer sequence, 5'-AAUAAUAUUCUU-3'. A dominant nuclear suppressor, SUV3-I, was previously isolated because it suppresses a dodecamer deletion at the 3' end of the var1 gene. We have tested the effects of SUV3-1 on a mutant containing two adjacent transversions within a dodecamer at the 3' end of fit1, a gene located within the 1,143-base-pair intron of the 21S rRNA gene, whose product is a site-specific endonuclease required in crosses for the quantitative transmission of that intron to 21S alleles that lack it. The fit1 dodecamer mutations blocked both intron transmission and dodecamer cleavage, neither of which was suppressed by SUV3-1 when present in heterozygous or homozygous configurations. Unexpectedly, we found that SUV3-1 completely blocked cleavage of the wild-type fit1 dodecamer and, in SUV3-1 homozygous crosses, intron conversion. In addition, SUV3-1 resulted in at least a 40-fold increase in the amount of excised intron accumulated. Genetic analysis showed that these phenotypes resulted from the same mutation. We conclude that cleavage of a wild-type dodecamer sequence at the 3' end of the fit1 gene is essential for fit1 expression.

Molecular Markers for Rapidly Identifying Candidate Genes in Chlamydomonas reinhardtii: ERY1 and ERY2 Encode Chloroplast Ribosomal Proteins

Genetics ◽  
2003 ◽  
Vol 164 (4) ◽  
pp. 1345-1353
Author(s):  
Amber K Bowers ◽  
Jennifer A Keller ◽  
Susan K Dutcher
Keyword(s):  
Molecular Markers ◽  
Chlamydomonas Reinhardtii ◽  
Candidate Genes ◽  
Splice Site ◽  
Genomic Dna ◽  
Ribosomal Proteins ◽  
Genomic Sequence ◽  
Point Mutations ◽  
Acceptor Site ◽  
Wild Type

Abstract To take advantage of available expressed sequence tags and genomic sequence, we have developed 64 PCR-based molecular markers in Chlamydomonas reinhardtii that map to the 17 linkage groups. These markers will allow the rapid association of a candidate gene sequence with previously identified mutations. As proof of principle, we have identified the genes encoded by the ERY1 and ERY2 loci. Mendelian mutations that confer resistance to erythromycin define three unlinked nuclear loci in C. reinhardtii. Candidate genes ribosomal protein L4 (RPL4) and L22 (RPL22) are tightly linked to the ERY1 locus and ERY2 locus, respectively. Genomic DNA for RPL4 from wild type and five mutant ery1 alleles was amplified and sequenced and three different point mutations were found. Two different glycine residues (G102 and G112) are replaced by aspartic acid and both are in the unstructured region of RPL4 that lines the peptide exit tunnel of the chloroplast ribosome. The other two alleles change a splice site acceptor site. Genomic DNA for RPL22 from wild type and three mutant ery2 alleles was amplified and sequenced and revealed three different point mutations. Two alleles have premature stop codons and one allele changes a splice site acceptor site.

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