Biomaterial Database

Overexpression of the RNR1 gene rescues Saccharomyces cerevisiae mutants in the mitochondrial DNA polymerase-encoding MIP1 gene. 1995

N Lecrenier, and F Foury

Unité de Biochimie Physiologique, Université Catholique de Louvain, Louvain-la-Neuve, Belgium.

A multicopy suppressor gene which rescues the temperature-sensitive growth defect of Saccharomyces cerevisiae mutants in the mitochondrial DNA (mtDNA) polymerase-encoding MIP1 gene has been isolated and identified as the RNR1 gene. This gene, whose transcript is cell cycle-regulated and mainly expressed at the G1 to S phase transition, encodes the large subunit of ribonucleotide reductase. This enzyme catalyses a limiting step in the production of deoxynucleotides needed for DNA synthesis. The presence of a high copy number of the RNR1 gene also decreases the accumulation of rho- mutants observed in diploids that harbour a single copy of the MIP1 gene. In cell cycle-synchronised cells, the presence of a high copy number of RNR1 does not modify its cell cycle transcription regulation and increases its transcript level by a factor of 10 throughout the cell cycle. Our results show that an increased supply of dNTPs in mitochondria can stimulate the mtDNA polymerase activity and indicate that the dNTP concentration may be rate limiting for the replication of mtDNA.

UI	MeSH Term	Description	Entries
D008928	Mitochondria	Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)	Mitochondrial Contraction,Mitochondrion,Contraction, Mitochondrial,Contractions, Mitochondrial,Mitochondrial Contractions
D002453	Cell Cycle	The complex series of phenomena, occurring between the end of one CELL DIVISION and the end of the next, by which cellular material is duplicated and then divided between two daughter cells. The cell cycle includes INTERPHASE, which includes G0 PHASE; G1 PHASE; S PHASE; and G2 PHASE, and CELL DIVISION PHASE.	Cell Division Cycle,Cell Cycles,Cell Division Cycles,Cycle, Cell,Cycle, Cell Division,Cycles, Cell,Cycles, Cell Division,Division Cycle, Cell,Division Cycles, Cell
D003001	Cloning, Molecular	The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.	Molecular Cloning
D004256	DNA Polymerase I	A DNA-dependent DNA polymerase characterized in prokaryotes and may be present in higher organisms. It has both 3'-5' and 5'-3' exonuclease activity, but cannot use native double-stranded DNA as template-primer. It is not inhibited by sulfhydryl reagents and is active in both DNA synthesis and repair.	DNA Polymerase alpha,DNA-Dependent DNA Polymerase I,Klenow Fragment,DNA Pol I,DNA Dependent DNA Polymerase I,Polymerase alpha, DNA
D004259	DNA-Directed DNA Polymerase	DNA-dependent DNA polymerases found in bacteria, animal and plant cells. During the replication process, these enzymes catalyze the addition of deoxyribonucleotide residues to the end of a DNA strand in the presence of DNA as template-primer. They also possess exonuclease activity and therefore function in DNA repair.	DNA Polymerase,DNA Polymerases,DNA-Dependent DNA Polymerases,DNA Polymerase N3,DNA Dependent DNA Polymerases,DNA Directed DNA Polymerase,DNA Polymerase, DNA-Directed,DNA Polymerases, DNA-Dependent,Polymerase N3, DNA,Polymerase, DNA,Polymerase, DNA-Directed DNA,Polymerases, DNA,Polymerases, DNA-Dependent DNA
D005800	Genes, Fungal	The functional hereditary units of FUNGI.	Fungal Genes,Fungal Gene,Gene, Fungal
D005838	Genotype	The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.	Genogroup,Genogroups,Genotypes
D012264	Ribonucleotide Reductases		Ribonucleotide Reductase,Reductase, Ribonucleotide,Reductases, Ribonucleotide
D012441	Saccharomyces cerevisiae	A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.	Baker's Yeast,Brewer's Yeast,Candida robusta,S. cerevisiae,Saccharomyces capensis,Saccharomyces italicus,Saccharomyces oviformis,Saccharomyces uvarum var. melibiosus,Yeast, Baker's,Yeast, Brewer's,Baker Yeast,S cerevisiae,Baker's Yeasts,Yeast, Baker
D013489	Suppression, Genetic	Mutation process that restores the wild-type PHENOTYPE in an organism possessing a mutationally altered GENOTYPE. The second "suppressor" mutation may be on a different gene, on the same gene but located at a distance from the site of the primary mutation, or in extrachromosomal genes (EXTRACHROMOSOMAL INHERITANCE).	Suppressor Mutation,Genetic Suppression,Genetic Suppressions,Mutation, Suppressor,Mutations, Suppressor,Suppressions, Genetic,Suppressor Mutations