A missense mutation in the nuclear gene coding for the mitochondrial aspartyl-tRNA synthetase suppresses a mitochondrial tRNA(Asp) mutation

The nuclear suppressor allele NSM3 in strain FF1210-6C/170-E22 (E22), which suppresses a mutation of the yeast mitochondrial tRNA(Asp)gene in Saccharomyces cerevisiae, was cloned and identified. To isolate the NSM3 allele, a genomic DNA library using the vector YEp13 was constructed from strain E22....

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Bibliographic Details
Published in:Nucleic acids research 2000-04, Vol.28 (7), p.1542-1547
Main Authors: Chiang, C S, Liaw, G J
Format: Article
Language:English
Subjects:
Alleles
Amino Acid Sequence
Aspartate-tRNA Ligase - genetics
Cell Nucleus - genetics
Cloning, Molecular
DNA, Fungal - genetics
DNA, Mitochondrial - genetics
Escherichia coli - genetics
Gene Amplification
Genes, Fungal
Mitochondria - enzymology
Molecular Sequence Data
Mutation, Missense
Plasmids - genetics
RNA, Transfer, Asp - genetics
Saccharomyces cerevisiae - enzymology
Saccharomyces cerevisiae - genetics
Sequence Homology, Amino Acid
Suppression, Genetic
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Summary:The nuclear suppressor allele NSM3 in strain FF1210-6C/170-E22 (E22), which suppresses a mutation of the yeast mitochondrial tRNA(Asp)gene in Saccharomyces cerevisiae, was cloned and identified. To isolate the NSM3 allele, a genomic DNA library using the vector YEp13 was constructed from strain E22. Nine YEp13 recombinant plasmids were isolated and shown to suppress the mutation in the mitochondrial tRNA(Asp)gene. These nine plasmids carry a common 4. 5-kb chromosomal DNA fragment which contains an open reading frame coding for yeast mitochondrial aspartyl-tRNA synthetase (AspRS) on the basis of its sequence identity to the MSD1 gene. The comparison of NSM3 DNA sequences between the suppressor and the wild-type version, cloned from the parental strain FF1210-6C/170, revealed a G to A transition that causes the replacement of amino acid serine (AGU) by an asparagine (AAU) at position 388. In experiments switching restriction fragments between the wild type and suppressor versions of the NSM3 gene, the rescue of respiratory deficiency was demonstrated only when the substitution was present in the construct. We conclude that the base substitution causes the respiratory rescue and discuss the possible mechanism as one which enhances interaction between the mutated tRNA(Asp)and the suppressor version of AspRS.
ISSN:1362-4962
DOI:10.1093/nar/28.7.1542