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ExtraTrain: a database of Extragenic regions and Transcriptional information in prokaryotic organisms.

BACKGROUND: Transcriptional regulation processes are the principal mechanisms of adaptation in prokaryotes. In these processes, the regulatory proteins and the regulatory DNA signals located in extragenic regions are the key elements involved. As all extragenic spaces are putative regulatory regions, ExtraTrain covers all extragenic regions of available genomes and regulatory proteins from bacteria and archaea included in the UniProt database. DESCRIPTION: ExtraTrain provides integrated and easily manageable information for 679816 extragenic regions and for the genes delimiting each of them. In addition ExtraTrain supplies a tool to explore extragenic regions, named Palinsight, oriented to detect and search palindromic patterns. This interactive visual tool is totally integrated in the database, allowing the search for regulatory signals in user defined sets of extragenic regions. The 26046 regulatory proteins included in ExtraTrain belong to the families AraC/XylS, ArsR, AsnC, Cold shock domain, CRP-FNR, DeoR, GntR, IclR, LacI, LuxR, LysR, MarR, MerR, NtrC/Fis, OmpR and TetR. The database follows the InterPro criteria to define these families. The information about regulators includes manually curated sets of references specifically associated to regulator entries. In order to achieve a sustainable and maintainable knowledge database ExtraTrain is a platform open to the contribution of knowledge by the scientific community providing a system for the incorporation of textual knowledge. CONCLUSION: ExtraTrain is a new database for exploring Extragenic regions and Transcriptional information in bacteria and archaea. ExtraTrain database is available at http://www.era7.com/ExtraTrain/.

Archaea↗

Web-based resources for comparative genomics.

The available web-based genome data and related resources provide great opportunities for biomedical scientists to identify functional elements in a particular genome region or to explore the evolutionary pattern of genome dynamics. Comparative genomics is an indispensable tool for achieving these goals. Because of the broad scope of comparative genomics, it is difficult to address all of its aspects in this short survey. A few currently 'hot' topics have therefore been selected and a brief review of the availability of web-based databases and software is given.

Animals↗

Conservation of the binding site for the arginine repressor in all bacterial lineages.

BACKGROUND: The arginine repressor ArgR/AhrC is a transcription factor universally conserved in bacterial genomes. Its recognition signal (the ARG box), a weak palindrome, is also conserved between genomes, despite a very low degree of similarity between individual sites within a genome. Thus, the arginine repressor is different from two other universal transcription factors - HrcA, whose recognition signal is very strongly conserved both within and between genomes, and LexA/DinR, whose signal is strongly conserved within, but not between, genomes. The arginine regulon is well studied in Escherichia coli and to some extent in Bacillus subtilis and some other genomes. Here, we apply the comparative genomic approach to the prediction of the ArgR-binding sites in all completely sequenced bacterial genomes. RESULTS: Orthologs of ArgR/AhrC were identified in the complete genomes of E. coli, Haemophilus influenzae, Vibrio choleras, B. subtilis, Mycobacterium tuberculosis, Thermotoga maritima, Chlamydia pneumoniae and Deinococcus radiodurans. Candidate arginine repressor binding sites were identified upstream of arginine transport and metabolism genes. CONCLUSIONS: We found that the ArgR/AhrC recognition signal is conserved in all genomes that contain genes encoding orthologous transcription factors of this family. All genomes studied except M. tuberculosis contain ABC transport cassettes (related to the Art system of E. coli) belonging to the candidate arginine regulons.

Bacteria↗

Serendipitous discovery of Wolbachia genomes in multiple Drosophila species.

BACKGROUND: The Trace Archive is a repository for the raw, unanalyzed data generated by large-scale genome sequencing projects. The existence of this data offers scientists the possibility of discovering additional genomic sequences beyond those originally sequenced. In particular, if the source DNA for a sequencing project came from a species that was colonized by another organism, then the project may yield substantial amounts of genomic DNA, including near-complete genomes, from the symbiotic or parasitic organism. RESULTS: By searching the publicly available repository of DNA sequencing trace data, we discovered three new species of the bacterial endosymbiont Wolbachia pipientis in three different species of fruit fly: Drosophila ananassae, D. simulans, and D. mojavensis. We extracted all sequences with partial matches to a previously sequenced Wolbachia strain and assembled those sequences using customized software. For one of the three new species, the data recovered were sufficient to produce an assembly that covers more than 95% of the genome; for a second species the data produce the equivalent of a 'light shotgun' sampling of the genome, covering an estimated 75-80% of the genome; and for the third species the data cover approximately 6-7% of the genome. CONCLUSIONS: The results of this study reveal an unexpected benefit of depositing raw data in a central genome sequence repository: new species can be discovered within this data. The differences between these three new Wolbachia genomes and the previously sequenced strain revealed numerous rearrangements and insertions within each lineage and hundreds of novel genes. The three new genomes, with annotation, have been deposited in GenBank.

Animals↗

Integrating AlphaFold2 models and clinical data to improve the assessment of Short Linear Motifs (SLiMs) and their variants' pathogenicity.

Short Linear Motifs (SLiMs) are protein functionally relevant regions that mediate reversible protein-protein interactions. Variants that disrupt SLiMs can lead to numerous Mendelian diseases. Although various bioinformatic tools have been developed to identify SLiMs, most suffer from low specificity. In our previous work, we demonstrated that integrating sequence variant information with structural analysis can enhance the prediction of true functional SLiMs while simultaneously generating tolerance matrices that indicate whether each of the 19 possible single amino acid substitutions (SASs) is tolerated. However, the scarcity of representative crystallographic structures of SLiM-receptor complexes posed a significant limitation. In this study, we demonstrate that these interactions can be modeled using AlphaFold2 (AF2) to generate high-quality structures that serve as input for our MotSASi method. These AF2-derived structures show robust performance, both in reproducing known structures deposited in the Protein Data Bank (PDB) and in reflecting the deleterious effects of known sequence variants. This updated version of MotSASi expands the repertoire of high-confidence predicted SLiMs and provides a comprehensive catalog of variants located within SLiMs, along with their respective deleteriousness assessments. When compared to AlphaMissense, MotSASi demonstrates superior performance in predicting variant deleteriousness. By contributing to the accurate identification and interpretation of variants, this work aligns with ACMG/AMP standards and aims to improve diagnostic rates in clinical genomics.

Humans↗

Bioinformatic approaches to assigning protein function from novel sequence data.

The current pace of functional genomic initiatives and genome sequencing projects has provided researchers with a bewildering array of sequence and biological data to analyze. The disease system-driven approach to identifying key genes frequently identifies nucleotide and protein sequences for which the gene and protein function are not known in sufficient detail to allow informed follow-up. Using a range of bioinformatic tools and sequence-based clues, most of unassigned sequences can now be annotated. This chapter takes as an example an unannotated expressed sequence tag, describing how to identify its related gene, and how to annotate the encoded protein using sequence, profile, and structure-based annotation methodologies.

Computational Biology↗

Comprehensive search for cysteine cathepsins in the human genome.

Our study was aimed at examinating whether or not the human genome encodes for previously unreported cysteine cathepsins. To this end, we used analyses of the genome sequence and mRNA expression levels. The program TBLASTN was employed to scan the draft sequence of the human genome for the 11 known cysteine cathepsins. The cathepsin-like segments in the genome were inspected, filtered, and annotated. In addition to the known cysteine cathepsins, the scan identified three pseudogenes, closely related to cathepsin L, on chromosome 10, as well as two remote homologs, tubulointerstitial protein antigen and tubulointerstitial protein antigen-related protein. No new members of the family were identified. mRNA expression profiles for 10 known human cysteine cathepsins showed varying expression levels in 46 different human tissues and cell lines. No expression of any of the three cathepsin L-like pseudogenes was found. Based on these results, it is likely that to date all human cysteine cathepsins are known.

Cathepsins↗

PathoGene: a pathogen coding sequence discovery and analysis resource.

PathoGene is a web-based resource that streamlines the process of predicting genes in microorganisms and designs PCR primers for amplification to facilitate sequence analysis and experimentation. PathoGene currently supports primer design for every complete microbial, viral, and fungal genome as cataloged in GenBank by the National Center for Biotechnology Information (NCBI; http://www.ncbi.nlm.nih.gov/). The resulting primers can then be subjected to a stand-alone Basic Local Alignment Search Tool (BLAST) system called PathoBLAST in which the predicted PCR product and/or primers can be compared against the genome of interest or a similar genome to find related genes or estimate primer quality.

Bacillus anthracis↗

MultiPrimer: software for multiplex primer design.

This study presents a novel application, MultiPrimer, to assist users to design multiplex PCR primers. MultiPrimer adopts an algorithm based on a genetic algorithm and can efficiently solve the multi-objective optimisation problem. A match pattern model is proposed to speed up examination of the specificity constraint. MultiPrimer is able to find a set of primer pairs simultaneously for a set of gene family sequences and multiple targets for a single cDNA sequence. A public version of the MultiPrimer software is available from http://edith.cse.nsysu.edu.tw/new/software/MultiPrimer.htm.

Algorithms↗

Codon usage and bias in mitochondrial genomes of parasitic platyhelminthes.

Sequences of the complete protein-coding portions of the mitochondrial (mt) genome were analysed for 6 species of cestodes (including hydatid tapeworms and the pork tapeworm) and 5 species of trematodes (blood flukes and liver- and lung-flukes). A near-complete sequence was also available for an additional trematode (the blood fluke Schistosoma malayensis). All of these parasites belong to a large flatworm taxon named the Neodermata. Considerable variation was found in the base composition of the protein-coding genes among these neodermatans. This variation was reflected in statistically-significant differences in numbers of each inferred amino acid between many pairs of species. Both convergence and divergence in nucleotide, and hence amino acid, composition was noted among groups within the Neodermata. Considerable variation in skew (unequal representation of complementary bases on the same strand) was found among the species studied. A pattern is thus emerging of diversity in the mt genome in neodermatans that may cast light on evolution of mt genomes generally.

Amino Acid Sequence↗

Cultured gill-derived Neoparamoeba pemaquidensis fails to elicit amoebic gill disease (AGD) in Atlantic salmon Salmo salar.

Amoebic gill disease (AGD) affects the culture of Atlantic salmon Salmo salar in the southeast of Tasmania. The disease is characterised by the presence of epizoic Neoparamoeba spp. in association with hyperplastic gill tissue. Gill-associated amoebae trophozoites were positively selected by plastic adherence for culture in seawater, where they proliferated using heat-killed E. coli as a nutrient source. One isolate of gill-harvested amoebae designated NP251002 was morphologically consistent to N. pemaquidensis under light, fluorescence and transmission electron microscopy. Rabbit anti-N. pemaquidensis antiserum bound to NP251002, and N. pemaquidensis small subunit (SSU) ribosomal DNA (18S rDNA) was detected in NP251002 genomic DNA preparations using PCR. A high degree of similarity in the alignment of the NP251002 18S rDNA PCR amplicon sequence with reference isolates of N. pemaquidensis suggested conspecificity. While short-term culture (72 h) of gill-harvested amoebae does not affect the capacity of amoebae to induce AGD, Atlantic salmon challenged with NP251002 after the trophozoites had been 34 and 98 d in culture exhibited neither gross nor histological evidence of AGD. It is not known if NP251002 were avirulent at the time of isolation, had down-regulated putative virulence factors or virulence was inhibited by the culture conditions. Therefore, the time in culture could be a limiting factor in maintaining virulence using the culture technique described here.

Animals↗

Carotenoid biosynthesis in cyanobacteria: structural and evolutionary scenarios based on comparative genomics.

Carotenoids are widely distributed pigments in nature and their biosynthetic pathway has been extensively studied in various organisms. The recent access to the overwhelming amount genomic data of cyanobacteria has given birth to a novel approach called comparative genomics. The putative enzymes involved in the carotenoid biosynthesis among the cyanobacteria were determined by similarity-based tools. The reconstruction of biosynthetic pathway was based on the related enzymes. It is interesting to find that nearly all the cyanobacteria share quite similar pathway to synthesize beta-carotene except for Gloeobacter violaceus PCC 7421. The enzymes, crtE-B-P-Qb-L, involved in the upstream pathway are more conserved than the subsequent ones (crtW-R). In addition, many carotenoid synthesis enzymes exhibit diversity in structure and function. Such examples in the families of zeta -carotene desaturase, lycopene cylases and carotene ketolases were described in this article. When we mapped these crt genes to the cyanobacterial genomes, the crt genes showed great structural variation among species. All of them are dispersed on the whole chromosome in contrast to the linear adjacent distribution of the crt gene cluster in other eubacteria. Moreover, in unicellular cyanobacteria, each step of the carotenogenic pathway is usually catalyzed by one gene product, whereas multiple ketolase genes are found in filamentous cyanobacteria. Such increased numbers of crt genes and their correlation to the ecological adaptation were carefully discussed.

Bacteria↗

Comparative analysis of the Arabidopsis and rice expressed sequence tag (EST) sets.

Large numbers of expressed sequence tags (ESTs) have now been generated from a variety of model organisms. In plants, substantial collections of ESTs are available for Arabidopsis and rice, in each case representing significant proportions of the estimated total numbers of genes. Large-scale comparisons of Arabidopsis and rice sequences are especially interesting due to the fact that these two species are representatives of the two subclasses of the flowering plants (Dicotyledonae and Monocotyledonae, respectively). Here we present the results of systematic analysis of the Arabidopsis and rice EST sets. Non-redundant sets of sequences from Arabidopsis and rice were first separately derived and then combined so that gene families in common between the two species could be identified. Our results show that 58% of non-singleton ESTs are derived from genes in gene families common to the two species. These gene families constitute the basis of a core set of higher plant genes.

Arabidopsis↗

Complete nucleotide sequence analysis of a vaccine strain and a field isolate of foot-and-mouth disease virus serotype Asia1 with an insertion in VP1 genomic region.

Complete nucleotide sequences except the poly (C) tract and poly (A) tail of a vaccine strain (IND 491/97) and an atypical field isolate (IND 321/01) of Foot-and-mouth disease virus (FMDV) serotype Asia1 are described. Amino acid (aa) sequence analysis of the VP1 protein of the field isolate revealed that the latter has 212 instead of 210 or 211 aa found in the so far available sequences of other FMDV isolates of Asia1 serotype. The insertion was localized in the hypervariable region of aa 130-160 of VP1 protein. Nucleotide sequencing of the entire genome was therefore carried out to detect changes in other parts of the genome, if any, besides VP1, which could contribute to its fitness. An 8.16 kb sequence of IND 491/97 and an 8.162 kb sequence of IND 321/01 were compared with each other and also with the known sequence of IND 63/72, another vaccine strain of serotype Asia1. Comparison of the entire polyprotein coding (L to 3D) region of IND 321/01 with those of the two Asia1 vaccine strains (IND 63/72 and IND 491/97) revealed no significant differences. A similar comparison of IND 491/97 with IND 63/72 revealed variability across the entire length of the genome. In addition to the capsid-coding region, sequence variability was also observed in non-structural proteins albeit to different extent. This study shows that in the gene pool of serotype Asia1 at least three groups of isolates/strains are present with respect to the length of VP1 protein.

Amino Acid Sequence↗

A comparative analysis of highly conserved sex-determining genes between Apis mellifera and Drosophila melanogaster.

A comparison of the most conserved sex-determining genes between the fruit fly, Drosophila melanogaster, and the honey bee, Apis mellifera, was performed with bioinformatics tools developed for computational molecular biology. An initial set of protein sequences already described in the fruit fly as participants of the sex-determining cascade was retrieved from the Gene Ontology database (http://www.geneontology.org/) and aligned against a database of protein sequences predicted from the honey bee genome. The doublesex (dsx) gene is considered one of the most conserved sex-determining genes among metazoans, and a male-specific partial cDNA of putative A. mellifera dsx gene (Amdsx) was identified experimentally. The theoretical predictions were developed in the context of sequence similarity. Experimental evidence indicates that dsx is present in embryos and larvae, and that it encodes a transcription factor widely conserved in metazoans, containing a DM DNA-binding domain implicated in the regulation of the expression of genes involved in sexual phenotype formation.

Animals↗

Characterization of adult alpha- and beta-globin genes in the zebrafish.

Developmental switching of hemoglobins (Hbs) occurs in most vertebrates, yet the cellular and molecular basis for this process remains elusive. The zebrafish is a new genetic and developmental system that can be used to study embryogenesis, and mutants with a variety of defects in hematopoiesis have recently been derived. To initiate our studies on Hb switching in this organism, we have characterized the globins expressed in the adult. Reversed-phase high performance liquid chromatography and mass spectrometric analyses of adult peripheral blood hemolysates showed that there are three major alpha globins and two beta globins in circulating erythroid cells. In addition, we have isolated and characterized zebrafish adult alpha- and beta-globin cDNA clones that encode some of these globins. High levels of alpha- and beta-globin gene expression were detected in adult erythroid cells, whereas embryonic erythroid cells expressed little, if any, of these RNAs. We have also shown that the alpha- and beta-globin genes are tightly linked on the same chromosome and are arrayed in a 3'-5' to 5'-3' configuration, respectively. The characterization of these genes and regulatory elements in this globin locus will provide insight into the process of globin gene transcription. With these reagents, future studies of Hb switching in zebrafish mutants with defective hematopoiesis will be possible.

Amino Acid Sequence↗

The sequence of the Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus genome.

The nucleotide sequence of the Helicoverpa armigera single-nucleocapsid nucleopolyhedrovirus (HaSNPV) DNA genome was determined and analysed. The circular genome encompasses 131,403 bp, has a G+C content of 39.1 mol% and contains five homologous regions with a unique pattern of repeats. Computer-assisted analysis revealed 135 putative ORFs of 150 nt or larger; 100 ORFs have homologues in Autographa californica multicapsid NPV (AcMNPV) and a further 15 ORFs have homologues in other baculoviruses such as Lymantria dispar MNPV (LdMNPV), Spodoptera exigua MNPV (SeMNPV) and Xestia c-nigrum granulovirus (XcGV). Twenty ORFs are unique to HaSNPV without homologues in GenBank. Among the six previously sequenced baculoviruses, AcMNPV, Bombyx mori NPV (BmNPV), Orgyia pseudotsugata MNPV (OpMNPV), SeMNPV, LdMNPV and XcGV, 65 ORFs are conserved and hence are considered as core baculovirus genes. The mean overall amino acid identity of HaSNPV ORFs was the highest with SeMNPV and LdMNPV homologues. Other than three 'baculovirus repeat ORFs' (bro) and two 'inhibitor of apoptosis' (iap) genes, no duplicated ORFs were found. A putative ORF showing similarity to poly(ADP-ribose) glycohydrolases (parg) was newly identified. The HaSNPV genome lacks a homologue of the major budded virus (BV) glycoprotein gene, gp64, of AcMNPV, BmNPV and OpMNPV. Instead, a homologue of SeMNPV ORF8, encoding the major BV envelope protein, has been identified. GeneParityPlot analysis suggests that HaSNPV, SeMNPV and LdMNPV (group II) have structural genomic features in common and are distinct from the group I NPVs and from the granuloviruses. Cluster alignment between group I and group II baculoviruses suggests that they have a common ancestor.

Base Composition↗