Dataset Information

Identification of new RNA modifying enzymes by iterative genome search using known modifying enzymes as probes.

ABSTRACT: The complete nucleotide sequences of the Haemophilus influenzae and Mycoplasma genitalium genomes and the partially sequenced Escherichia coli chromosome were analyzed to identify open reading frames (ORFs) likely to encode RNA modifying enzymes. The protein sequences of known RNA modifying enzymes from three families--m5U methyltransferases, psi synthases and 2'-O methyltransferases--were used as probes to search sequence databases for homologs. ORFs identified as homologous to the initial probes were retrieved and used as new probes against the databases in an iterative manner until no more homologous ORFs could be identified. Using this approach, we have identified two new m5U methyltransferases, seven new psi synthases and four new 2'-O methyltransferases in E. coli. Many of the ORFs found in E.coli have direct genetic counterparts (orthologs) in one or both of H.influenzae and M.genitalium. Since there is a near-complete knowledge of RNA modifications in E.coli, functional activities of the proteins encoded by the identified ORFs were proposed based on the level of conservation of the ORFs and the modified nucleotides.

SUBMITTER: Gustafsson C

PROVIDER: S-EPMC146159 | biostudies-other | 1996 Oct

REPOSITORIES: biostudies-other

ACCESS DATA

Publications

Identification of new RNA modifying enzymes by iterative genome search using known modifying enzymes as probes.

Gustafsson C C Reid R R Greene P J PJ Santi D V DV

Nucleic acids research 19961001 19

The complete nucleotide sequences of the Haemophilus influenzae and Mycoplasma genitalium genomes and the partially sequenced Escherichia coli chromosome were analyzed to identify open reading frames (ORFs) likely to encode RNA modifying enzymes. The protein sequences of known RNA modifying enzymes from three families--m5U methyltransferases, psi synthases and 2'-O methyltransferases--were used as probes to search sequence databases for homologs. ORFs identified as homologous to the initial prob ...[more]

PMID: 8871555

Similar Datasets

Project description:BackgroundIn all domains of life, transfer RNA (tRNA) molecules contain modified nucleosides. Modifications to tRNAs affect their coding capacity and influence codon-anticodon interactions. Nucleoside modification deficiencies have a diverse range of effects, from decreased virulence in bacteria, neural system disease in human, and gene expression and stress response changes in plants. The purpose of this study was to identify genes involved in tRNA modification in the model plant Arabidopsis thaliana, to understand the function of nucleoside modifications in plant growth and development.ResultsIn this study, we established a method for analyzing modified nucleosides in tRNAs from the model plant species, Arabidopsis thaliana and hybrid aspen (Populus tremula × tremuloides). 21 modified nucleosides in tRNAs were identified in both species. To identify the genes responsible for the plant tRNA modifications, we performed global analysis of the Arabidopsis genome for candidate genes. Based on the conserved domains of homologs in Sacccharomyces cerevisiae and Escherichia coli, more than 90 genes were predicted to encode tRNA modifying enzymes in the Arabidopsis genome. Transcript accumulation patterns for the genes in Arabidopsis and the phylogenetic distribution of the genes among different plant species were investigated. Transcripts for the majority of the Arabidopsis candidate genes were found to be most abundant in rosette leaves and shoot apices. Whereas most of the tRNA modifying gene families identified in the Arabidopsis genome was found to be present in other plant species, there was a big variation in the number of genes present for each family.Through a loss of function mutagenesis study, we identified five tRNA modification genes (AtTRM10, AtTRM11, AtTRM82, AtKTI12 and AtELP1) responsible for four specific modified nucleosides (m1G, m2G, m7G and ncm5U), respectively (two genes: AtKTI12 and AtELP1 identified for ncm5U modification). The AtTRM11 mutant exhibited an early-flowering phenotype, and the AtELP1 mutant had narrow leaves, reduced root growth, an aberrant silique shape and defects in the generation of secondary shoots.ConclusionsUsing a reverse genetics approach, we successfully isolated and identified five tRNA modification genes in Arabidopsis thaliana. We conclude that the method established in this study will facilitate the identification of tRNA modification genes in a wide variety of plant species.

Project description:Gene clusters are groups of genes that are co-locally conserved across various genomes, not necessarily in the same order. Their discovery and analysis is valuable in tasks such as gene annotation and prediction of gene interactions, and in the study of genome organization and evolution. The discovery of conserved gene clusters in a given set of genomes is a well studied problem, but with the rapid sequencing of prokaryotic genomes a new problem is inspired. Namely, given an already known gene cluster that was discovered and studied in one genomic dataset, to identify all the instances of the gene cluster in a given new genomic sequence. Thus, we define a new problem in comparative genomics, denoted PQ-TREE SEARCH that takes as input a PQ-tree T representing the known gene orders of a gene cluster of interest, a gene-to-gene substitution scoring function h, integer arguments [Formula: see text] and [Formula: see text], and a new sequence of genes S. The objective is to identify in S approximate new instances of the gene cluster; These instances could vary from the known gene orders by genome rearrangements that are constrained by T, by gene substitutions that are governed by h, and by gene deletions and insertions that are bounded from above by [Formula: see text] and [Formula: see text], respectively. We prove that PQ-TREE SEARCH is NP-hard and propose a parameterized algorithm that solves the optimization variant of PQ-TREE SEARCH in [Formula: see text] time, where [Formula: see text] is the maximum degree of a node in T and [Formula: see text] is used to hide factors polynomial in the input size. The algorithm is implemented as a search tool, denoted PQFinder, and applied to search for instances of chromosomal gene clusters in plasmids, within a dataset of 1,487 prokaryotic genomes. We report on 29 chromosomal gene clusters that are rearranged in plasmids, where the rearrangements are guided by the corresponding PQ-trees. One of these results, coding for a heavy metal efflux pump, is further analysed to exemplify how PQFinder can be harnessed to reveal interesting new structural variants of known gene clusters.

Dataset Information

Identification of new RNA modifying enzymes by iterative genome search using known modifying enzymes as probes.

Publications

Identification of new RNA modifying enzymes by iterative genome search using known modifying enzymes as probes.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets