Organellar tRNAs: Biosynthesis and Function

Martín, Nancy

doi:10.1128/9781555818333.ch9

Cited by 12 publications

(4 citation statements)

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“…Letters A–E specify regions where tRNA genes are coded, and correspond to (c). ( b ) phylogenetic distance of Buchnera taxa; number labels ( 1–5 ) correspond to (c). tRNA expression is presented as Reads Per Kilobase of exon model per Million mapped reads (RPKM).…”

Section: Resultsmentioning

confidence: 99%

“…Most endosymbionts retain the universal genetic code, but exceptions do exist among the tiniest genomes, in which UGA is sometimes recoded from Stop to Trp (16,17). In contrast, organelle tRNAs and their translational machinery are highly divergent from those of most bacteria (1,3,8,18). The question still remains as to how endosymbiont tRNAs and translational mechanisms differ from those of ancestral free-living genomes that are not reduced.…”

Section: Introductionmentioning

confidence: 99%

“…The robust nature of the genetic code and numerous genome-encoded mechanisms promote translational accuracy ( 1 , 2 ), thus preventing deleterious events such as the reassignment of codons that can alter the function of thousands of genes. Nevertheless, tRNAs and the genetic code sometimes do change, especially in genomes undergoing size reduction as exemplified by mitochondria and plastids ( 1 , 3 , 4 ). These organelle genomes, which are derived from genomes of symbiotic bacteria ( 5 , 6 ), exhibit the most extreme cases of architectural alterations such as an increase in molecular evolutionary rate, inability to recombine, and massive gene loss that sometimes leads to tRNA loss and changes in the genetic code ( 7 ).…”

Section: Introductionmentioning

confidence: 99%

“…These organelle genomes, which are derived from genomes of symbiotic bacteria ( 5 , 6 ), exhibit the most extreme cases of architectural alterations such as an increase in molecular evolutionary rate, inability to recombine, and massive gene loss that sometimes leads to tRNA loss and changes in the genetic code ( 7 ). Organelles encode a limited set of proteins and rely on other co-occurring genomes for enzymes and tRNAs ( 3 , 8 , 9 ).…”

Section: Introductionmentioning

confidence: 99%

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Altered tRNA characteristics and 3′ maturation in bacterial symbionts with reduced genomes

Hansen

Moran

2012

Nucleic Acids Research

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Translational efficiency is controlled by tRNAs and other genome-encoded mechanisms. In organelles, translational processes are dramatically altered because of genome shrinkage and horizontal acquisition of gene products. The influence of genome reduction on translation in endosymbionts is largely unknown. Here, we investigate whether divergent lineages of Buchnera aphidicola , the reduced-genome bacterial endosymbiont of aphids, possess altered translational features compared with their free-living relative, Escherichia coli . Our RNAseq data support the hypothesis that translation is less optimal in Buchnera than in E. coli . We observed a specific, convergent, pattern of tRNA loss in Buchnera and other endosymbionts that have undergone genome shrinkage. Furthermore, many modified nucleoside pathways that are important for E. coli translation are lost in Buchnera . Additionally, Buchnera ’s A + T compositional bias has resulted in reduced tRNA thermostability, and may have altered aminoacyl-tRNA synthetase recognition sites. Buchnera tRNA genes are shorter than those of E. coli , as the majority no longer has a genome-encoded 3' CCA; however, all the expressed, shortened tRNAs undergo 3′ CCA maturation. Moreover, expression of tRNA isoacceptors was not correlated with the usage of corresponding codons. Overall, our data suggest that endosymbiont genome evolution alters tRNA characteristics that are known to influence translational efficiency in their free-living relative.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Altered tRNA characteristics and 3′ maturation in bacterial symbionts with reduced genomes

Hansen

Moran

2012

Nucleic Acids Research

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Mitochondrial tRNA mutations and disease

et al. 2010

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Mitochondrial (mt-) tRNA (MTT) gene mutations are an important cause of human morbidity and are associated with a wide range of pathology, from isolated organ-specific diseases such as myopathy or hearing loss, through to multisystem disorders with encephalopathy, gastrointestinal dysmotility, and life-threatening cardiomyopathy. Our understanding of how MTT mutations cause disease remains poor and progress has been hampered by the complex interaction of genotype with phenotype that can result in patients who harbor the same mutation exhibiting starkly contrasting phenotypes, whereas other (genetically heterogeneous) patients manifest clinically identical syndromes. A further complexity is the highly polymorphic nature of mitochondrial DNA (mtDNA), which must temper any reflex assumptions of pathogenicity for novel MTT substitutions. Nevertheless significant progress is being made and we shall review the methods employed to identify and characterize MTT mutations as pathogenic. Also important is our understanding of the molecular processes involved and we shall discuss the data available on two of the most studied MTT mutations (m.8344A > G and m.3243A > G) as well as other potential pathogenic mechanisms. Knowledge of factors influencing the inheritance of MTT mutations, and therefore the likelihood of disease transmission, is of particular importance to female patients. At present, the factors determining transmission remain elusive, but we shall examine several possible mechanisms and discuss the evidence for each. Finally, a number of different yeast and mouse models are currently used to investigate mitochondrial disease and we will assess the importance of and difficulties associated with each model as well as the future of possible therapies for patients with mitochondrial disease.

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Plastid and Plant Mitochondrial RNA Processing and RNA Stability

Marchfelder

Binder

Molecular Biology and Biotechnology of Plant Organelles

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Organellar tRNAs: Biosynthesis and Function

Cited by 12 publications

References 153 publications

Altered tRNA characteristics and 3′ maturation in bacterial symbionts with reduced genomes

Altered tRNA characteristics and 3′ maturation in bacterial symbionts with reduced genomes

Mitochondrial tRNA mutations and disease

Plastid and Plant Mitochondrial RNA Processing and RNA Stability

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