Isolation of the Chlamydomonas regulatory gene NIT2 by transposon tagging.

In the unicellular alga Chlamydomonas, two anterior flagella are positioned with 180° rotational symmetry, such that the flagella beat with the effective strokes in opposite directions (Hoops, H.J., and G.B. Witman. 1983. J. Cell Biol. 97:902–908). The vfl1 mutation results in variable numbers and positioning of flagella and basal bodies (Adams, G.M.W., R.L. Wright, and J.W. Jarvik. 1985. J. Cell Biol. 100:955–964). Using a tagged allele, we cloned the VFL1 gene that encodes a protein of 128 kD with five leucine-rich repeat sequences near the NH2 terminus and a large α-helical–coiled coil domain at the COOH terminus. An epitope-tagged gene construct rescued the mutant phenotype and expressed a tagged protein (Vfl1p) that copurified with basal body flagellar apparatuses. Immunofluorescence experiments showed that Vfl1p localized with basal bodies and probasal bodies. Immunogold labeling localized Vfl1p inside the lumen of the basal body at the distal end. Distribution of gold particles was rotationally asymmetric, with most particles located near the doublet microtubules that face the opposite basal body. The mutant phenotype, together with the localization results, suggest that Vfl1p plays a role in establishing the correct rotational orientation of basal bodies. Vfl1p is the first reported molecular marker of the rotational asymmetry inherent to basal bodies.

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“…Chlamydomonas DNA was isolated as described by Schnell and Lefebvre (1993). RNA was isolated using the method of Wilkerson et al (1994).…”

Section: Isolation and Blotting Of Nucleic Acidsmentioning

confidence: 99%

The Vfl1 Protein in Chlamydomonas Localizes in a Rotationally Asymmetric Pattern at the Distal Ends of the Basal Bodies

Silflow

LaVoie

Tam

et al. 2001

The Journal of Cell Biology

106

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“…However, the synthesis of the enzymes appears to be regulated by nitrate derepression and induction (e.g. Hipkin et al 1983) and N-metabolite repression (reviewed by Solomonson & Barber (1990); Schnell & Lefebvre (1993)). Synthesis is repressed by the presence of an, as yet, unidenti- fied organic compound which is most likely an early product of inorganic N assimilation (Solomonson & Barber 1990).…”

Section: (C) Nitrate Reduction To Ammonium (Figures 2 3; Equation 6x In Table 6)mentioning

confidence: 99%

Modelling the interactions between ammonium and nitrate uptake in marine phytoplankton

Flynn

Fasham

Hipkin

1997

Phil. Trans. R. Soc. Lond. B

132

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CONTENTS page 1. Introduction 1625 2. Theoretical bases and model development 1626 (a) Model construction 1626 (b) Control of transport (figures 2, 3; equation 5.x in table 5) 1629 (c) Nitrate reduction to ammonium (figures 2, 3; equation 6.x in table 6) 1630 (d) Assimilation of intracellular ammonium and growth (figures 2, 3; equation 7.x in table 7) 1633 (e) Operation in light-dark cycles 1635 (f) Parametrization 1635 3. Results 1635 (a) Simulation of ammonium-nitrate interactions 1635 (b) Sensitivity analysis 1637 4. Discussion 1639 References 1643 SUMMARY An empirically based mathematical model is presented which can simulate the major features of the interactions between ammonium and nitrate transport and assimilation in phytoplankton. The model (ammonium-nitrate interaction model), which is configured to simulate a generic microalga rather than a specified species, is constructed on simplified biochemical bases. A major requirement for parametrization is that the N:C ratio of the algae must be known and that transport and internal pool sizes need to be expressed per unit of cell C. The model uses the size of an internal pool of an early organic product of N assimilation (glutamine) to regulate rapid responses in ammoniumnitrate interactions. The synthesis of enzymes for the reduction of nitrate through to ammonium is induced by the size of the internal nitrate pool and repressed by the size of the glutamine pool. The assimilation of intracellular ammonium (into glutamine) is considered to be a constitutive process subjected to regulation by the size of the glutamine pool. Longer term responses have been linked to the nutrient history of the cell using the N:C cell quota. N assimilation in darkness is made a function of the amount of surplus C present and thus only occurs at low values of N:C. The model can simulate both qualitative and quantitative temporal shifts in the ammonium-nitrate interaction, while inclusion of a derivation of the standard quota model enables a concurrent simulation of cell growth and changes in nutrient status.

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“…It was anticipated that aminoterminal sequences of E. coli related GTPase is responsible to target the mitochondria, development of seeds are detained by the introduction of mutation in E. coli related GTPase allele through site selected transposon mutagenesis (Neuvéglise et al, 1998;Ouyang et al, 2007). In Arabidopsis, there were two variants of ERG genes identified in the Genomic data, first gene was found in in chloroplast were named as AtERG1 and other gene were found in mitochondria were named as AtERG2 (Schnell and Lefebvre, 1993;Schwarz-Sommer et al, 1985).…”

Section: Era-like Gtp Binding Proteins In Plantsmentioning

confidence: 99%

Era-like GTP protein gene expression in rice

et al. 2022

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The mutations are genetic changes in the genome sequences and have a significant role in biotechnology, genetics, and molecular biology even to find out the genome sequences of a cell DNA along with the viral RNA sequencing. The mutations are the alterations in DNA that may be natural or spontaneous and induced due to biochemical reactions or radiations which damage cell DNA. There is another cause of mutations which is known as transposons or jumping genes which can change their position in the genome during meiosis or DNA replication. The transposable elements can induce by self in the genome due to cellular and molecular mechanisms including hypermutation which caused the localization of transposable elements to move within the genome. The use of induced mutations for studying the mutagenesis in crop plants is very common as well as a promising method for screening crop plants with new and enhanced traits for the improvement of yield and production. The utilization of insertional mutations through transposons or jumping genes usually generates stable mutant alleles which are mostly tagged for the presence or absence of jumping genes or transposable elements. The transposable elements may be used for the identification of mutated genes in crop plants and even for the stable insertion of transposable elements in mutated crop plants. The guanine nucleotide-binding (GTP) proteins have an important role in inducing tolerance in rice plants to combat abiotic stress conditions.

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Isolation of the Chlamydomonas regulatory gene NIT2 by transposon tagging.

Cited by 165 publications

References 34 publications

The Vfl1 Protein in Chlamydomonas Localizes in a Rotationally Asymmetric Pattern at the Distal Ends of the Basal Bodies

The Vfl1 Protein in Chlamydomonas Localizes in a Rotationally Asymmetric Pattern at the Distal Ends of the Basal Bodies

Modelling the interactions between ammonium and nitrate uptake in marine phytoplankton

Era-like GTP protein gene expression in rice

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