<i>Saccharomyces cerevisiae</i> Tti2 Regulates PIKK Proteins and Stress Response

Hoffman, Kyle S.; Duennwald, Martin L.; Karagiannis, Jim; Genereaux, Julie; McCarton, Alexander S; Brandl, Christopher J.

doi:10.1534/g3.116.029520

Cited by 24 publications

(46 citation statements)

References 45 publications

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“…In addition, the dek38-Dsg revertants that were isolated in our screen all show complete restoration of the WT sequence. This result is also consistent with findings in yeast wherein C-terminal end truncations of TTI2 are also lethal (27).…”

Section: Discussionsupporting

confidence: 92%

Maize defective kernel mutant generated by insertion of a Ds element in a gene encoding a highly conserved TTI2 cochaperone

Garcia

Dooner

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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We have used the newly engineered transposable element to tag a gene that gives rise to a defective kernel () phenotype. requires the autonomous element for transposition. Upon excision, it leaves a short DNA footprint that can create in-frame and frameshift insertions in coding sequences. Therefore, we could create alleles of the tagged gene that confirmed causation of the phenotype by the insertion. The mutation, designated , is embryonic lethal, has a defective basal endosperm transfer (BETL) layer, and results in a smaller seed with highly underdeveloped endosperm. The maize gene encodes a TTI2 (Tel2-interacting protein 2) molecular cochaperone. In yeast and mammals, TTI2 associates with two other cochaperones, TEL2 (Telomere maintenance 2) and TTI1 (Tel2-interacting protein 1), to form the triple T complex that regulates DNA damage response. Therefore, we cloned the maize and homologs and showed that TEL2 can interact with both TTI1 and TTI2 in yeast two-hybrid assays. The three proteins regulate the cellular levels of phosphatidylinositol 3-kinase-related kinases (PIKKs) and localize to the cytoplasm and the nucleus, consistent with known subcellular locations of PIKKs. displays reduced pollen transmission, indicating TTI2's importance in male reproductive cell development.

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Section: Discussionsupporting

confidence: 92%

Maize defective kernel mutant generated by insertion of a Ds element in a gene encoding a highly conserved TTI2 cochaperone

Garcia

Dooner

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…The protein in question must therefore show significant function when present at relatively low levels. Other examples of proteins that function at such reduced levels are the proline isomerase Ess1 (Gemmill et al 2005) and the cochaperone Tti2 (Hoffman et al 2016.…”

Section: Discussionmentioning

confidence: 99%

Mistranslating tRNA identifies a deleterious S213P mutation in theSaccharomyces cerevisiae eco1-1allele

Zhu

Berg

Yang

et al. 2020

Preprint

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Mistranslation occurs when an amino acid not specified by the standard genetic code is incorporated during translation. Since the ribosome does not read the amino acid, tRNA variants aminoacylated with a non-cognate amino acid or containing a non-cognate anticodon dramatically increase the frequency of mistranslation. In a systematic genetic analysis, we identified a suppression interaction between tRNA Ser UGG, G26A, which mistranslates proline codons by inserting serine, and eco1-1, a temperature sensitive allele of the gene encoding an acetyltransferase required for sister chromatid cohesion. The suppression was partial with a tRNA that inserts alanine at proline codons and not apparent for a tRNA that inserts serine at arginine codons. Sequencing of the eco1-1 allele revealed a mutation that would convert the highly conserved serine 213 within β7 of the GCN5-related N-acetyltransferase core to proline. Mutation of P213 in eco1-1 back to the wild-type serine restored function of the enzyme at elevated temperature. Our results indicate the utility of mistranslating tRNA variants to identify functionally relevant mutations and identify eco1 as a reporter for mistranslation. We propose that mistranslation could be used as a tool to treat genetic disease.

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“…The L187P mutation has a profound effect on cell growth in stress conditions (26). The structure of Tti2 is unknown, but L187 is situated in a predicted alpha helix, which is likely disrupted by the Pro mutation.…”

Section: Discussionmentioning

confidence: 99%

Genetic selection for mistranslation rescues a defective co-chaperone in yeast

Hoffman

Berg

Shilton

et al. 2016

Nucleic Acids Research

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Despite the general requirement for translation fidelity, mistranslation can be an adaptive response. We selected spontaneous second site mutations that suppress the stress sensitivity caused by a Saccharomyces cerevisiae tti2 allele with a Leu to Pro mutation at residue 187, identifying a single nucleotide mutation at the same position (C70U) in four tRNAProUGG genes. Linkage analysis and suppression by SUF9G3:U70 expressed from a centromeric plasmid confirmed the causative nature of the suppressor mutation. Since the mutation incorporates the G3:U70 identity element for alanyl-tRNA synthetase into tRNAPro, we hypothesized that suppression results from mistranslation of Pro187 in Tti2L187P as Ala. A strain expressing Tti2L187A was not stress sensitive. In vitro, tRNAProUGG (C70U) was mis-aminoacylated with alanine by alanyl–tRNA synthetase, but was not a substrate for prolyl–tRNA synthetase. Mass spectrometry from protein expressed in vivo and a novel GFP reporter for mistranslation confirmed substitution of alanine for proline at a rate of ∼6%. Mistranslating cells expressing SUF9G3:U70 induce a partial heat shock response but grow nearly identically to wild-type. Introducing the same G3:U70 mutation in SUF2 (tRNAProAGG) suppressed a second tti2 allele (tti2L50P). We have thus identified a strategy that allows mistranslation to suppress deleterious missense Pro mutations in Tti2.

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Saccharomyces cerevisiae Tti2 Regulates PIKK Proteins and Stress Response

Cited by 24 publications

References 45 publications

Maize defective kernel mutant generated by insertion of a Ds element in a gene encoding a highly conserved TTI2 cochaperone

Maize defective kernel mutant generated by insertion of a Ds element in a gene encoding a highly conserved TTI2 cochaperone

Mistranslating tRNA identifies a deleterious S213P mutation in theSaccharomyces cerevisiae eco1-1allele

Genetic selection for mistranslation rescues a defective co-chaperone in yeast

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