Identification of a gene controlling levels of the copper response regulator 1 transcription factor in Chlamydomonas reinhardtii.

Oxygen prevents hydrogen production in Chlamydomonas (Chlamydomonas reinhardtii), in part by inhibiting the transcription of hydrogenase genes. We developed a screen for mutants showing constitutive accumulation of iron hydrogenase 1 (HYDA1) transcripts in normoxia. A reporter gene required for ciliary motility placed under the control of the HYDA1 promoter conferred motility only in hypoxia.

Mutation of negative regulatory gene encoding an FBXO3 protein results in normoxic expression of genes in .

Oxygen is known to prevent hydrogen production in Chlamydomonas, both by inhibiting the hydrogenase enzyme and by preventing the accumulation of HYDA-encoding transcripts. We developed a screen for mutants showing constitutive accumulation of transcripts in the presence of oxygen. A reporter gene required for ciliary motility, placed under the control of the promoter, conferred motility only in hypoxic conditions.

The U.S. Culture Collection Network Lays the Foundation for Progress in Preservation of Valuable Microbial Resources.

The U.S. Culture Collection Network was formed in 2012 by a group of culture collection scientists and stakeholders in order to continue the progress established previously through efforts of an ad hoc group.

The UNI1 and UNI2 genes function in the transition of triplet to doublet microtubules between the centriole and cilium in Chlamydomonas.

One fundamental role of the centriole in eukaryotic cells is to nucleate the growth of cilia. The unicellular alga Chlamydomonas reinhardtii provides a simple genetic system to study the role of the centriole in ciliogenesis. Wild-type cells are biflagellate, but "uni" mutations result in failure of some centrioles (basal bodies) to assemble cilia (flagella).

The Uni2 phosphoprotein is a cell cycle regulated component of the basal body maturation pathway in Chlamydomonas reinhardtii.

Mutations in the UNI2 locus in Chlamydomonas reinhardtii result in a "uniflagellar" phenotype in which flagellar assembly occurs preferentially from the older basal body and ultrastructural defects reside in the transition zones. The UNI2 gene encodes a protein of 134 kDa that shares 20.5% homology with a human protein.

Molecular map of the Chlamydomonas reinhardtii nuclear genome.

We have prepared a molecular map of the Chlamydomonas reinhardtii genome anchored to the genetic map. The map consists of 264 markers, including sequence-tagged sites (STS), scored by use of PCR and agarose gel electrophoresis, and restriction fragment length polymorphism markers, scored by use of Southern blot hybridization. All molecular markers tested map to one of the 17 known linkage groups of C.

The bld1 mutation identifies the Chlamydomonas osm-6 homolog as a gene required for flagellar assembly.

Insertional mutagenesis procedures in Chlamydomonas have facilitated the identification and characterization of dozens of genes required for the assembly and motility of flagella in Chlamydomonas. Many of these genes have been found to have homologs in animal systems. Here we describe a new gene required for flagellar assembly.

The Vfl1 Protein in Chlamydomonas localizes in a rotationally asymmetric pattern at the distal ends of the basal bodies.

In the unicellular alga Chlamydomonas, two anterior flagella are positioned with 180 degrees rotational symmetry, such that the flagella beat with the effective strokes in opposite directions (Hoops, H.J., and G.

Gamma-tubulin in Chlamydomonas: characterization of the gene and localization of the gene product in cells.

In addition to their role in nucleating the assembly of axonemal microtubules, basal bodies often are associated with a microtubule organizing center (MTOC) for cytoplasmic microtubules. In an effort to define molecular components of the basal body apparatus in Chlamydomonas reinhardtii, genomic and cDNA clones encoding gamma-tubulin were isolated and sequenced. The gene, present in a single copy in the Chlamydomonas genome, encodes a protein with a predicted molecular mass of 52,161 D and 73% and 65% conservation with gamma-tubulin from higher plants and humans, respectively.

SF-assemblin in Chlamydomonas: sequence conservation and localization during the cell cycle.

Previously, SF-assemblin has been identified as the filament-forming component of the striated microtubule-associated fibers (SMAFs), which emerge from the basal bodies in several green flagellates. We have sequenced cDNAs coding for SF-assemblin from Chlalmydomonas reinhardtii and C. eugametos.

Isolation and characterization of glutamine synthetase genes in Chlamydomonas reinhardtii.

To elucidate the role of glutamine synthetase (GS) in nitrogen assimilation in the green alga Chlamydomonas reinhardtii we used maize GS1 (the cytosolic form) and GS2 (the chloroplastic form) cDNAs as hybridization probes to isolate C. reinhardtii cDNA clones. The amino acid sequences derived from the C.

Identification of intrinsic dimer and overexpressed monomeric forms of gamma-tubulin in Sf9 cells infected with baculovirus containing the Chlamydomonas gamma-tubulin sequence.

A new member of the tubulin superfamily, gamma-tubulin, is localized at microtubule-organizing centers (MTOCs) in a variety of organisms. Chlamydomonas cDNA coding for the full-length sequence of gamma-tubulin was expressed in insect ovarian Sf9 cells using the baculovirus expression system. Approximately half of the induced 52 kDa gamma-tubulin was recovered in the supernatant after centrifugation of Sf9 cell lysates at 18,000 g for 15 minutes.

gamma-Tubulin in Arabidopsis: gene sequence, immunoblot, and immunofluorescence studies.

gamma-Tubulin is a protein associated with microtubule (Mt)-organizing centers in a variety of eukaryotic cells. Unfortunately, little is known about such centers in plants. Genomic and partial cDNA clones encoding two gamma-tubulins of Arabidopsis were isolated and sequenced.

Characterization of four new beta-tubulin genes and their expression during male flower development in maize (Zea mays L.).

Four different beta-tubulin coding sequences were isolated from a cDNA library prepared from RNA from maize seedling shoots. The four genes (designated tub4, tub6, tub7 and tub8) represented by these cDNA clones together with the tub1 and tub2 genes reported previously encode six beta-tubulin isotypes with 90-97.5% amino acid sequence identity.

Differential expression of six glutamine synthetase genes in Zea mays.

The maize genome has been shown to contain six glutamine synthetase (GS) genes with at least four different expression patterns. Noncoding 3' gene-specific probes were constructed from all six GS cDNA clones and used to examine transcript levels in selected organs by RNA gel blot hybridization experiments. The transcript of the single putative chloroplastic GS2 gene was found to accumulate primarily in green tissues, whereas the transcripts of the five putative GS1 genes were shown to accumulate preferentially in roots.

A mutation in the alpha 1-tubulin gene of Chlamydomonas reinhardtii confers resistance to anti-microtubule herbicides.

A mutation in the alpha 1-tubulin gene of Chlamydomonas reinhardtii was isolated by using the amiprophos-methyl-resistant mutation apm1-18 as a background to select new mutants that showed increased resistance to the drug. The upA12 mutation caused twofold resistance to amiprophos-methyl and oryzalin, and twofold hypersensitivity to the microtubule-stabilizing drug taxol, suggesting that the mutation enhanced microtubule stability. The resistance mutation was semi-dominant and mapped to the same interval on linkage group III as the alpha 1-tubulin gene.

Mapping of beta-tubulin genomic sequences in hexaploid oat (Arena sativa L.).

The allohexaploid nature of Avena sativa L. (2n=6x=42) and the availability of aneuploid lines was exploited in designing a strategy for mapping beta-tubulin sequences in the oat genome. Evidence for a minimum of eight beta-tubulin genes was obtained by Southern-blot analysis.

Semi-constitutive expression of an Arabidopsis thaliana alpha-tubulin gene.

In Arabidopsis tissues, the pool of tubulin protein is provided by the expression of multiple alpha-tubulin and beta-tubulin genes. Previous evidence suggested that the TUA2 alpha-tubulin gene was expressed in all organs of mature plants. We now report a more detailed analysis of TUA2 expression during plant development.