Swinger RNAs in the Human Mitochondrial Transcriptome

Transcriptomes include coding and non-coding RNAs and RNA fragments with no apparent homology to parent genomes. Non-canonical transcriptions systematically transforming template DNA sequences along precise rules explain some transcripts. Among these systematic transformations, 23 systematic exchanges between nucleotides, i.e. 9 symmetric (X ↔ Y, e.g. C ↔ T) and 14 asymmetric (X → Y → Z → X, e.g. A → T → G → A) exchanges. Here, comparisons between mitochondrial swinger RNAs previously detected in a complete human transcriptome dataset (including cytosolic RNAs) and swinger RNAs detected in purified mitochondrial transcriptomic data (not including cytosolic RNAs) show high reproducibility and exclude cytosolic contaminations. These results based on next-generation sequencing Illumina technology confirm detections of mitochondrial swinger RNAs in GenBank’s EST database sequenced by the classical Sanger method, assessing the existence of swinger polymerizations

PCR diagnosis of tick-borne pathogens in Maharashtra state, India indicates fitness cost associated with carrier infections is greater for crossbreed than native cattle breeds

Tick-borne pathogens (TBP) are responsible for significant economic losses to cattle production, globally. This is particularly true in countries like India where TBP constrain rearing of high yielding Bos taurus, as they show susceptibility to acute tick borne disease (TBD), most notably tropical theileriosis caused by Theileria annulata. This has led to a programme of cross breeding Bos taurus (Holstein-Friesian or Jersey) with native Bos indicus (numerous) breeds to generate cattle that are more resistant to disease. However, the cost to fitness of subclinical carrier infection in crossbreeds relative to native breeds is unknown, but could represent a significant hidden economic cost. In this study, a total of 1052 bovine blood samples, together with associated data on host type, sex and body score, were collected from apparently healthy animals in four different agro-climatic zones of Maharashtra state. Samples were screened by PCR for detection of five major TBPs: T. annulata, T. orientalis, B. bigemina, B. bovis and Anaplasma spp.. The results demonstrated that single and co-infection with TBP are common, and although differences in pathogen spp. prevalence across the climatic zones were detected, simplistic regression models predicted that host type, sex and location are all likely to impact on prevalence of TBP. In order to remove issues with autocorrelation between variables, a subset of the dataset was modelled to assess any impact of TBP infection on body score of crossbreed versus native breed cattle (breed type). The model showed significant association between infection with TBP (particularly apicomplexan parasites) and poorer body condition for crossbreed animals. These findings indicate potential cost of TBP carrier infection on crossbreed productivity. Thus, there is a case for development of strategies for targeted breeding to combine productivity traits with disease resistance, or to prevent transmission of TBP in India for economic benefit

Exploring putative unknown non-canonical transcriptions and translations

Le séquencage d'ARN et la spectrométrie de masse génèrent des RNA reads et des spectres peptidiques non-homologues à l'ADN. Les ignorer cause la perte d'informations génétiques. Nous explorons deux transcription noncanoniques, identifiant et expliquant RNAs et peptides mitochondriaux humains (non prédits par le genome nucléaire). 1) Échanges nucléotidiques systématiques: les échanges systématiques de nucleotides dans l'ARN (swinger RNA, 23 échanges, 9 symmétriques (X↔Y) et 14 asymmétriques (X→Y→Z→X). Les résultats sur les swinger ARNs sont reproductibles entre transcriptomes de souches mitochondriales pures et de la cellule entire, pour deux méthodes différentes de séquencage. Nous identifions des ARNs précédemment inconnus dans les non-Hodgkin lymphomes associés à HIV et des cellules cancéreuses. 2) Délétions nucléotidiques systématiques: des nombres spécifiques de nucléotides sont systématiquement délétés après chaque trinucléotide transcript, produisant des ARNs délétés (delRNAs). Au total 227 delRNAs (1-12 nucléotides délétés) sont confirmés dans trois bases de donnees, les transcriptomes de cellules humaines entières et de mitochondries pures, et la base de EST de GenBank. Les résultats indiquent que des peptides mitochondriaux sont produits à partir de traduction normale de delRNAs et de traduction de mRNAs normaux par des anticodons rallongés. Nous détectons aussi des peptides chimériques, codés par des codons normaux avec des parties contigües codées par des codons rallongés. Cette thèse détecte des transcriptions et traductions noncanoniques dans la mitochondrie humaine, et la transcription swinger de chromosomes humains nucléaires.RNA sequencing and mass spectrometry generate RNA reads and peptide spectra nonhomologous to the template DNA. Ignoring them results in losing valuable genetic information. We explored two non-canonical transcriptions, identified and explained RNA reads and peptides from human mitochondria (unpredicted by nuclear chromosomes). 1) Systematic nucleotide exchanges: systematic nucleotide exchanges in RNAs (called swinger RNAs) (23 exchanges, i.e. 9 symmetric (X↔Y) and 14 asymmetric (X→Y→Z→X)). Swinger RNA results are reproducable: data from purified human mitochondrial lines confirm whole-cell transcriptome data obtained by different sequencing methods. We identified previously unknown RNAs in HIV-associated non-Hodgkin's lymphoma and cancer genomes. 2) Systematic nucleotide deletions: specific nucleotide numbers are systematically deleted after each transcribed trinucleotide, producing deletion RNAs (delRNAs). A total of 227 delRNAs (1-12 deleted nucleotides) were confirmed in 3 datasets, human whole-cell and purified mitochondrial transcriptomes, and the Genbank human EST database. These map on mitochondrial protein-coding genes & the hypervariable 2 dloop. Results indicate mitochondrial peptides produced by regular delRNA translation and translation of regular mRNAs by expanded anticodons. We also detected chimeric peptides partly encoded by regular codons, and contiguous parts by expanded codons. Results show non-canonical transcriptions and translations in human mitochondria, and swinger transcription of human nuclear chromosomes

Transcripts with systematic nucleotide deletion of 1-12 nucleotide in human mitochondrion suggest potential non-canonical transcription

International audienceRaw transcriptomic data contain numerous RNA reads whose homology with template DNA doesn't match canonical transcription. Transcriptome analyses usually ignore such nonca-nonical RNA reads. Here, analyses search for noncanonical mitochondrial RNAs systematically deleting 1 to 12 nucleotides after each transcribed nucleotide triplet, producing deletion-RNAs (delRNAs). We detected delRNAs in the human whole cell and purified mito-chondrial transcriptomes, and in Genbank's human EST database corresponding to systematic deletions of 1 to 12 nucleotides after each transcribed trinucleotide. DelRNAs detected in both transcriptomes mapped along with 55.63% of the EST delRNAs. A bias exists for delRNAs covering identical mitogenomic regions in both transcriptomic and EST datasets. Among 227 delRNAs detected in these 3 datasets, 81.1% and 8.4% of delRNAs were mapped on mitochondrial coding and hypervariable region 2 of dloop. Del-transcription analyses of GenBank's EST database confirm observations from whole cell and purified mitochondrial transcriptomes, eliminating the possibility that detected delRNAs are false positives matches, cytosolic DNA/RNA nuclear contamination or sequencing artefacts. These detected delRNAs are enriched in frameshift-inducing homopolymers and are poor in frameshift-preventing circular code codons (a set of 20 codons which regulate reading frame detection, over-and underrepresented in coding and other frames of genes, respectively) suggesting a motif-based regulation of non-canonical transcription. These findings show that rare non-canonical transcripts exist. Such non canonical del-transcription does increases mitochondrial coding potential and non-coding regulation of intracellular mechanisms , and could explain the dark DNA conundrum

Genetic Code Optimization for Cotranslational Protein Folding: Codon Directional Asymmetry Correlates with Antiparallel Betasheets, tRNA Synthetase Classes

A new codon property, codon directional asymmetry in nucleotide content (CDA), reveals a biologically meaningful genetic code dimension: palindromic codons (first and last nucleotides identical, codon structure XZX) are symmetric (CDA = 0), codons with structures ZXX/XXZ are 5′/3′ asymmetric (CDA = −1/1; CDA = −0.5/0.5 if Z and X are both purines or both pyrimidines, assigning negative/positive (−/+) signs is an arbitrary convention). Negative/positive CDAs associate with (a) Fujimoto's tetrahedral codon stereo-table; (b) tRNA synthetase class I/II (aminoacylate the 2′/3′ hydroxyl group of the tRNA's last ribose, respectively); and (c) high/low antiparallel (not parallel) betasheet conformation parameters. Preliminary results suggest CDA-whole organism associations (body temperature, developmental stability, lifespan). Presumably, CDA impacts spatial kinetics of codon-anticodon interactions, affecting cotranslational protein folding. Some synonymous codons have opposite CDA sign (alanine, leucine, serine, and valine), putatively explaining how synonymous mutations sometimes affect protein function. Correlations between CDA and tRNA synthetase classes are weaker than between CDA and antiparallel betasheet conformation parameters. This effect is stronger for mitochondrial genetic codes, and potentially drives mitochondrial codon-amino acid reassignments. CDA reveals information ruling nucleotide-protein relations embedded in reversed (not reverse-complement) sequences (5′-ZXX-3′/5′-XXZ-3′). Keywords: Secondary structure, Codon-amino acid assignment, Mitochondrial genetic code, Synonymous codon, Alpha helix, Beta tur

Chimeric Translation for Mitochondrial Peptides: Regular and Expanded Codons

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Systematic Nucleotide Exchange Analysis of ESTs From the Human Cancer Genome Project Report: Origins of 347 Unknown ESTs Indicate Putative Transcription of Non-Coding Genomic Regions

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Identification of Noncanonical Transcripts Produced by Systematic Nucleotide Exchanges in HIV-Associated Centroblastic Lymphoma

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