scholarly journals De Novo Purine Synthesis in Arabidopsis thaliana (II. The PUR7 Gene Encoding 5[prime]-Phosphoribosyl-4-(N-Succinocarboxamide)-5-Aminoimidazole Synthetase Is Expressed in Rapidly Dividing Tissues)

1996 ◽  
Vol 112 (3) ◽  
pp. 905-917 ◽  
Author(s):  
J. F. Senecoff ◽  
E. C. McKinney ◽  
R. B. Meagher
Keyword(s):  
Arabidopsis Thaliana ◽  
De Novo ◽  
Gene Encoding ◽  
Purine Synthesis

scholarly journals The Drosophila melanogaster ade5 Gene Encodes a Bifunctional Enzyme for Two Steps in the de novo Purine Synthesis Pathway

Genetics ◽  
2000 ◽  
Vol 154 (3) ◽  
pp. 1239-1253
Author(s):  
Allyson F O'Donnell ◽  
Stanley Tiong ◽  
David Nash ◽  
Denise V Clark
Keyword(s):  
Drosophila Melanogaster ◽  
De Novo ◽  
Single Gene ◽  
Hybrid Dysgenesis ◽  
Induced Mutations ◽  
Gene Encoding ◽  
Purine Synthesis ◽  
E Coli ◽  
Gene Maps

Abstract Steps 6 and 7 of de novo purine synthesis are performed by 5-aminoimidazole ribonucleotide carboxylase (AIRc) and 4-[(N-succinylamino)carbonyl]-5-aminoimidazole ribonucleotide synthetase (SAICARs), respectively. In vertebrates, a single gene encodes AIRc-SAICARs with domains homologous to Escherichia coli PurE and PurC. We have isolated an AIRc-SAICARs cDNA from Drosophila melanogaster via functional complementation with an E. coli purC purine auxotroph. This cDNA encodes AIRc yet is unable to complement an E. coli purE mutant, suggesting functional differences between Drosophila and E. coli AIRc. In vertebrates, the AIRc-SAICARs gene shares a promoter region with the gene encoding phosphoribosylamidotransferase, which performs the first step in de novo purine synthesis. In Drosophila, the AIRc-SAICARs gene maps to section 11B4-14 of the X chromosome, while the phosphoribosylamidotransferase gene (Prat) maps to chromosome 3; thus, the close linkage of these two genes is not conserved in flies. Three EMS-induced X-linked adenine auxotrophic mutations, ade41, ade51, and ade52, were isolated. Two gammaradiation-induced (ade53 and ade54) and three hybrid dysgenesis-induced (ade55, ade56, and ade58) alleles were also isolated. Characterization of the auxotrophy and the finding that the hybrid dysgenesis-induced mutations all harbor P transposon sequences within the AIRc-SAICARs gene show that ade5 encodes AIRc-SAICARs.

scholarly journals APOK3, a pollen killer antidote in Arabidopsis thaliana

2021 ◽  
Author(s):  
Matthieu Simon ◽  
Stéphanie Durand ◽  
Anthony Ricou ◽  
Nathalie Vrielynck ◽  
Baptiste Mayjonade ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Natural Variation ◽  
De Novo ◽  
Chimeric Protein ◽  
The Other ◽  
Crop Breeding ◽  
Gene Encoding ◽  
Killing Activity ◽  
Parental Allele ◽  
Major Interest

AbstractAccording to the principles of heredity, each parental allele of hybrids equally participates in the progeny. At some loci, however, it happens that one allele is favored to the expense of the other. Gamete killers are genetic systems where one allele (the killer) triggers the death of the gametes carrying the other (killed) allele. They have been found in many organisms, and are of major interest to understand mechanisms of evolution and speciation. Gamete killers are particularly prevalent in plants, where they can compromise crop breeding. Here, we deciphered a pollen killer in Arabidopsis thaliana by exploiting natural variation, de novo genomic sequencing and mutants, and analyzing segregations in crosses. We found that the killer allele carries an antidote gene flanked by two elements mandatory for the killing activity. We identified the gene encoding the antidote, a chimeric protein addressed to mitochondria. This gene appeared in the species by association of domains recruited from other genes, and it recently underwent duplications within a highly variable locus, particularly in the killer genotypes. Exploring the species diversity, we identified sequence polymorphisms correlated with the antidote activity.

Identification of a single-copy gene encoding a Type I chlorophyll a/b-binding polypeptide of photosystem I in Arabidopsis thaliana

1992 ◽  
Vol 84 (4) ◽  
pp. 561-567 ◽  
Author(s):  
Poul E. Jensen ◽  
Michael Kristensen ◽  
Tine Hoff ◽  
Jan Lehmbeck ◽  
Bjarne M. Stummann ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Chlorophyll A ◽  
Photosystem I ◽  
Single Copy ◽  
Type I ◽  
Single Copy Gene ◽  
Gene Encoding ◽  
Copy Gene

scholarly journals Gain-of-function GABRB3 variants identified in vigabatrin-hypersensitive epileptic encephalopathies

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Nathan L Absalom ◽  
Vivian W Y Liao ◽  
Kavitha Kothur ◽  
Dinesh C Indurthi ◽  
Bruce Bennetts ◽  
...  
Keyword(s):  
De Novo ◽  
Drug Effects ◽  
Receptor Expression ◽  
Aminobutyric Acid ◽  
Loss Of Function ◽  
Molecular Phenotype ◽  
Gain Of Function ◽  
Gene Encoding ◽  
Epileptic Encephalopathies ◽  
Receptor Phenotype

Abstract Variants in the GABRB3 gene encoding the β3-subunit of the γ-aminobutyric acid type A ( receptor are associated with various developmental and epileptic encephalopathies. Typically, these variants cause a loss-of-function molecular phenotype whereby γ-aminobutyric acid has reduced inhibitory effectiveness leading to seizures. Drugs that potentiate inhibitory GABAergic activity, such as nitrazepam, phenobarbital or vigabatrin, are expected to compensate for this and thereby reduce seizure frequency. However, vigabatrin, a drug that inhibits γ-aminobutyric acid transaminase to increase tonic γ-aminobutyric acid currents, has mixed success in treating seizures in patients with GABRB3 variants: some patients experience seizure cessation, but there is hypersensitivity in some patients associated with hypotonia, sedation and respiratory suppression. A GABRB3 variant that responds well to vigabatrin involves a truncation variant (p.Arg194*) resulting in a clear loss-of-function. We hypothesized that patients with a hypersensitive response to vigabatrin may exhibit a different γ-aminobutyric acid A receptor phenotype. To test this hypothesis, we evaluated the phenotype of de novo variants in GABRB3 (p.Glu77Lys and p.Thr287Ile) associated with patients who are clinically hypersensitive to vigabatrin. We introduced the GABRB3 p.Glu77Lys and p.Thr287Ile variants into a concatenated synaptic and extrasynaptic γ-aminobutyric acid A receptor construct, to resemble the γ-aminobutyric acid A receptor expression by a patient heterozygous for the GABRB3 variant. The mRNA of these constructs was injected into Xenopus oocytes and activation properties of each receptor measured by two-electrode voltage clamp electrophysiology. Results showed an atypical gain-of-function molecular phenotype in the GABRB3 p.Glu77Lys and p.Thr287Ile variants characterized by increased potency of γ-aminobutyric acid A without change to the estimated maximum open channel probability, deactivation kinetics or absolute currents. Modelling of the activation properties of the receptors indicated that either variant caused increased chloride flux in response to low concentrations of γ-aminobutyric acid that mediate tonic currents. We therefore propose that the hypersensitivity reaction to vigabatrin is a result of GABRB3 variants that exacerbate GABAergic tonic currents and caution is required when prescribing vigabatrin. In contrast, drug strategies increasing tonic currents in loss-of-function variants are likely to be a safe and effective therapy. This study demonstrates that functional genomics can explain beneficial and adverse anti-epileptic drug effects, and propose that vigabatrin should be considered in patients with clear loss-of-function GABRB3 variants.

scholarly journals A new folate antimetabolite, 5,10-dideaza-5,6,7,8-tetrahydrofolate is a potent inhibitor of de novo purine synthesis

1989 ◽  
Vol 264 (1) ◽  
pp. 328-333 ◽  
Author(s):  
G P Beardsley ◽  
B A Moroson ◽  
E C Taylor ◽  
R G Moran
Keyword(s):  
De Novo ◽  
Potent Inhibitor ◽  
Purine Synthesis
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