Dataset Information

Identified Hybrid tRNA Structure Genes in Archaeal Genome.

ABSTRACT: Background:In Archaea, previous studies have revealed the presence of multiple intron-containing tRNAs and split tRNAs. The full unexpurgated analysis of archaeal tRNA genes remains a challenging task in the field of bioinformatics, because of the presence of various types of hidden tRNA genes in archaea. Here, we suggested a computational method that searched for widely separated genes encoding tRNA halves to generate suppressive variants of missing tRNAs. Objectives:The exploration of tRNA genes from a genome with varying hypotheses, among all three domain of life (eukaryotes, bacteria and archaea), has been rapidly identified in different ways in the field of bioinformatics. Like eukaryotic tRNA genes, it has been established that two separated regions of the coding sequence of a tRNA gene are essential and sufficient for promotion of transcription. Our objective is to find out the two essential regions in the genome sequence which comprises two halves of the hidden tRNAs. Material and Methods:Considering the existence of split tRNA genes widely separated throughout the genome, we developed our tRNA search algorithm to predict such separated tRNA genes by searching both a conserved terminal 5'- and 3'-motif of tRNA in agreement with the split hypothesis on the basis of cloverleaf prediction and precise insilico determination of bulge-helix-bulge secondary structure at the splice sites. Results:By a comprehensive search for all kinds of missing tRNA genes, we have constructed hybrid tRNA genes containing one essential region from tDNA (XYZ) and the other from tDNA (ABC), both from same species in the archaea. We have also found, this type of hybrid tRNA genes are identified in the different species of the archaea (XYZ ASN, ARG and MET; ABC ASP,SER, ARG and PRO).These hybrid split tRNA share a common structural motif called bulge-helix-bulge (BHB) a more relaxed bulge-helix loop (BHL), at the leader exon boundary and suggested to be evolutionary interrelated. Conclusions:Analysis of the complete genome sequences of Metallosphaera sedula DSM 5348, Desulfurococcus kamchatkensis 1221n and Ignicoccus hospitalis KIN4/I in archaea by our algorithm revealed that a number of hybrid tRNAs are constructed from different tDNAs . Asymmetric combination of 5' and 3' tRNA halves may have generated the diversity of tRNA molecules. Our study of hybrid tRNA genes will provide a new molecular basis for upcoming tRNA studies.

SUBMITTER: Mandal UR

PROVIDER: S-EPMC7080975 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Identified Hybrid tRNA Structure Genes in Archaeal Genome.

Mandal Uttam Roy UR Das Shib Sankar SS Chattopadhyay Brajadulal B Sahoo Satyabrata S

Iranian journal of biotechnology 20190901 3

<h4>Background</h4>In Archaea, previous studies have revealed the presence of multiple intron-containing tRNAs and split tRNAs. The full unexpurgated analysis of archaeal tRNA genes remains a challenging task in the field of bioinformatics, because of the presence of various types of hidden tRNA genes in archaea. Here, we suggested a computational method that searched for widely separated genes encoding tRNA halves to generate suppressive variants of missing tRNAs.<h4>Objectives</h4>The explorat ...[more]

PMID: 32195286

Similar Datasets

Project description:BACKGROUND: The process of horizontal gene transfer (HGT) is believed to be widespread in Bacteria and Archaea, but little comparative data is available addressing its occurrence in complete microbial genomes. Collection of high-quality, automated HGT prediction data based on phylogenetic evidence has previously been impractical for large numbers of genomes at once, due to prohibitive computational demands. DarkHorse, a recently described statistical method for discovering phylogenetically atypical genes on a genome-wide basis, provides a means to solve this problem through lineage probability index (LPI) ranking scores. LPI scores inversely reflect phylogenetic distance between a test amino acid sequence and its closest available database matches. Proteins with low LPI scores are good horizontal gene transfer candidates; those with high scores are not. DESCRIPTION: The DarkHorse algorithm has been applied to 955 microbial genome sequences, and the results organized into a web-searchable relational database, called the DarkHorse HGT Candidate Resource http://darkhorse.ucsd.edu. Users can select individual genomes or groups of genomes to screen by LPI score, search for protein functions by descriptive annotation or amino acid sequence similarity, or select proteins with unusual G+C composition in their underlying coding sequences. The search engine reports LPI scores for match partners as well as query sequences, providing the opportunity to explore whether potential HGT donor sequences are phylogenetically typical or atypical within their own genomes. This information can be used to predict whether or not sufficient information is available to build a well-supported phylogenetic tree using the potential donor sequence. CONCLUSION: The DarkHorse HGT Candidate database provides a powerful, flexible set of tools for identifying phylogenetically atypical proteins, allowing researchers to explore both individual HGT events in single genomes, and large-scale HGT patterns among protein families and genome groups. Although the DarkHorse algorithm cannot, by itself, provide definitive proof of horizontal gene transfer, it is a flexible, powerful tool that can be combined with slower, more rigorous methods in situations where these other methods could not otherwise be applied.

Project description:Archaeosine (G+) is a structurally complex modified nucleoside found quasi-universally in the tRNA of Archaea and located at position 15 in the dihydrouridine loop, a site not modified in any tRNA outside the Archaea G+ is characterized by an unusual 7-deazaguanosine core structure with a formamidine group at the 7-position. The location of G+ at position 15, coupled with its novel molecular structure, led to a hypothesis that G+ stabilizes tRNA tertiary structure through several distinct mechanisms. To test whether G+ contributes to tRNA stability and define the biological role of G+, we investigated the consequences of introducing targeted mutations that disrupt the biosynthesis of G+ into the genome of the hyperthermophilic archaeon Thermococcus kodakarensis and the mesophilic archaeon Methanosarcina mazei, resulting in modification of the tRNA with the G+ precursor 7-cyano-7-deazaguansine (preQ0) (deletion of arcS) or no modification at position 15 (deletion of tgtA). Assays of tRNA stability from in vitro-prepared and enzymatically modified tRNA transcripts, as well as tRNA isolated from the T. kodakarensis mutant strains, demonstrate that G+ at position 15 imparts stability to tRNAs that varies depending on the overall modification state of the tRNA and the concentration of magnesium chloride and that when absent results in profound deficiencies in the thermophily of T. kodakarensis IMPORTANCE Archaeosine is ubiquitous in archaeal tRNA, where it is located at position 15. Based on its molecular structure, it was proposed to stabilize tRNA, and we show that loss of archaeosine in Thermococcus kodakarensis results in a strong temperature-sensitive phenotype, while there is no detectable phenotype when it is lost in Methanosarcina mazei Measurements of tRNA stability show that archaeosine stabilizes the tRNA structure but that this effect is much greater when it is present in otherwise unmodified tRNA transcripts than in the context of fully modified tRNA, suggesting that it may be especially important during the early stages of tRNA processing and maturation in thermophiles. Our results demonstrate how small changes in the stability of structural RNAs can be manifested in significant biological-fitness changes.

Dataset Information

Identified Hybrid tRNA Structure Genes in Archaeal Genome.

Publications

Identified Hybrid tRNA Structure Genes in Archaeal Genome.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets