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Characterization and quality control of recombinant adenovirus vectors for gene therapy.

Highly purified recombinant adenovirus undergoes routine quality controls for identity, potency and purity prior to its use as a gene therapy vector. Quantitative characterization of infectivity is measurable by the expression of the DNA binding protein, an early adenoviral protein, in an immunofluorescence bioassay on permissive cells as a potency determinant. The specific particle count, a key quality indicator, is the total number of intact particles present compared to the number of infectious units. Electron microscopic analysis using negative staining gives a qualitative biophysical analysis of the particles eluted from anion-exchange HPLC. One purity assessment is accomplished via the documented presence and relative ratios of component adenoviral proteins as well as potential contaminants by reversed-phase HPLC of the intact virus followed by protein peak identification using MALDI-TOF mass spectrometry and subsequent data mining. Verification of the viral genome is performed and expression of the transgene is evaluated in in vitro systems for identity. Production lots are also evaluated for replication-competent adenovirus prior to human use. For adenovirus carrying the human IL-2 transgene, quantitative IL-2 expression is demonstrated by ELISA and cytokine potency by cytotoxic T lymphocyte assay following infection of permissive cells. Both quantitative and qualitative analyses show good batch to batch reproducibility under routine test conditions using validated methods.

Adenoviridae↗

The gene ncgl2918 encodes a novel maleylpyruvate isomerase that needs mycothiol as cofactor and links mycothiol biosynthesis and gentisate assimilation in Corynebacterium glutamicum.

Data mining of the Corynebacterium glutamicum genome identified 4 genes analogous to the mshA, mshB, mshC, and mshD genes that are involved in biosynthesis of mycothiol in Mycobacterium tuberculosis and Mycobacterium smegmatis. Individual deletion of these genes was carried out in this study. Mutants mshC- and mshD- lost the ability to produce mycothiol, but mutant mshB- produced mycothiol as the wild type did. The phenotypes of mutants mshC- and mshD- were the same as the wild type when grown in LB or BHIS media, but mutants mshC- and mshD- were not able to grow in mineral medium with gentisate or 3-hydroxybenzoate as carbon sources. C. glutamicum assimilated gentisate and 3-hydroxybenzoate via a glutathione-independent gentisate pathway. In this study it was found that the maleylpyruvate isomerase, which catalyzes the conversion of maleylpyruvate into fumarylpyruvate in the glutathione-independent gentisate pathway, needed mycothiol as a cofactor. This mycothiol-dependent maleylpyruvate isomerase gene (ncgl2918) was cloned, actively expressed, and purified from Escherichia coli. The purified mycothiol-dependent isomerase is a monomer of 34 kDa. The apparent Km and Vmax values for maleylpyruvate were determined to be 148.4 +/- 11.9 microM and 1520 +/- 57.4 micromol/min/mg, respectively (mycothiol concentration, 2.5 microM). Previous studies had shown that mycothiol played roles in detoxification of oxidative chemicals and antibiotics in streptomycetes and mycobacteria. To our knowledge, this is the first demonstration that mycothiol is essential for growth of C. glutamicum with gentisate or 3-hydroxybenzoate as carbon sources and the first characterization of a mycothiol-dependent maleylpyruvate isomerase.

Amino Acid Sequence↗

Phylogenomics Unveils the Complex Evolution of Retroviruses in Birds.

The rise of birds represents one of the major evolutionary transitions in the history of life. Yet, much remains obscure about the origins and diversification of viruses in birds. Endogenous retroviruses (ERVs), relics of past retroviral infections, provide molecular fossils for interrogating the evolution and ecology of retroviruses. Here, we perform phylogenomic mining of ERVs within the genomes of 758 bird species and identify more than 470,000 ERVs, revealing a highly diverse and complex retrovirus repertoire in birds. These ERVs greatly expand the diversity of retroviruses in birds, indicating that exogenous retroviruses characterized in birds to date are highly underestimated. The evolution of retroviruses in birds is shaped by both coevolution and cross-species transmission. Tens of retrovirus lineages originated during the early evolution of birds, four of which contribute to more than 90% of complete ERVs in birds. We also observe recent ERV activity across the bird phylogeny (particularly in Passeriformes). Moreover, we find that ERVs can mediate genome rearrangements, potentially facilitating the genome evolution of birds. Many bird retroviruses recruited genes of cellular provenience, which might drive the evolution of the genome complexity of retroviruses. Together, these results unveil a diverse and complex retrovirosphere in birds and provide insights into the intricate evolution of retrovirus-bird interaction.

Animals↗

BASC: an integrated bioinformatics system for Brassica research.

The BASC system provides tools for the integrated mining and browsing of genetic, genomic and phenotypic data. This public resource hosts information on Brassica species supporting the Multinational Brassica Genome Sequencing Project, and is based upon five distinct modules, ESTDB, Microarray, MarkerQTL, CMap and EnsEMBL. ESTDB hosts expressed gene sequences and related annotation derived from comparison with GenBank, UniRef and the genome sequence of Arabidopsis. The Microarray module hosts gene expression information related to genes annotated within ESTDB. MarkerQTL is the most complex module and integrates information on genetic markers, maps, individuals, genotypes and traits. Two further modules include an Arabidopsis EnsEMBL genome viewer and the CMap comparative genetic map viewer for the visualization and integration of genetic and genomic data. The database is accessible at http://bioinformatics.pbcbasc.latrobe.edu.au.

Arabidopsis↗

Characterisation and application of a bovine U6 promoter for expression of short hairpin RNAs.

BACKGROUND: The use of small interfering RNA (siRNA) molecules in animals to achieve double-stranded RNA-mediated interference (RNAi) has recently emerged as a powerful method of sequence-specific gene knockdown. As DNA-based expression of short hairpin RNA (shRNA) for RNAi may offer some advantages over chemical and in vitro synthesised siRNA, a number of vectors for expression of shRNA have been developed. These often feature polymerase III (pol. III) promoters of either mouse or human origin. RESULTS: To develop a shRNA expression vector specifically for bovine RNAi applications, we identified and characterised a novel bovine U6 small nuclear RNA (snRNA) promoter from bovine sequence data. This promoter is the putative bovine homologue of the human U6-8 snRNA promoter, and features a number of functional sequence elements that are characteristic of these types of pol. III promoters. A PCR based cloning strategy was used to incorporate this promoter sequence into plasmid vectors along with shRNA sequences for RNAi. The promoter was then used to express shRNAs, which resulted in the efficient knockdown of an exogenous reporter gene and an endogenous bovine gene. CONCLUSION: We have mined data from the bovine genome sequencing project to identify a functional bovine U6 promoter and used the promoter sequence to construct a shRNA expression vector. The use of this native bovine promoter in shRNA expression is an important component of our future development of RNAi therapeutic and transgenic applications in bovine species.

Animals↗

Causal relationship between educational attainment and the occurrence of venous thromboembolism.

BACKGROUND: The association between educational attainment (EA) and arterial thrombotic disease has been reported, but the causal relationship between EA and venous thromboembolism (VTE) is not clear. We aimed to assess the causal effect of EA on VTE using the two-sample mendelian randomization (MR) method. METHODS: Data mining was conducted on the genome wide association studies (GWAS), with exposure factor EA and outcome factor VTE. Two-sample Mendelian Randomization (TSMR) analysis was conducted, with the results obtained from the random effects inverse variance weighted method (IVW). Use the MR-Egger method for pleiotropy analysis and leave one method for sensitivity analysis to verify the reliability of the data. RESULTS: Genetically predicted decreased EA was associated with a decreased risk of VTE in both the FinnGen consortium and UK Biobank (FinnGen-VTE: OR = 0.848; 95% CI 0.776-0.927; P = 2.84 × 10-4; UKB-VTE OR = 0.996; 95% CI 0.994-0.999; P = 0.008) under a multiplicative random-effects IVW model. Results were consistent in all sensitivity analyses and no horizontal pleiotropy was detected. CONCLUSIONS: The MR technique instructed a potential inverse causative relationship between EA and occurrence of VTE. Therefore, patients with low EA should be more vigilant about the occurrence of VTE.

Venous Thromboembolism↗

Techniques in plant telomere biology.

The role model systems have played in understanding telomere biology has been enormous, and understanding has rapidly transferred to human telomere research. Most work using model organisms to study telomerase and nontelomerase-based telomere-maintenance systems has centered on yeasts, ciliates, and insects. But it is now timely to put considerably more effort into plant models for a number of reasons: (i) the rice and Arabidopsis genome sequencing projects make data mining possible; (ii) extensive collections of insertion mutants of Arabidopsis thaliana enable phenotypic effects of protein gene knockouts to be analyzed, including for those genes involved in telomere structure, function (including, for example, in meiosis), and maintenance; and (iii) the variability of plant telomeres is considerable and ranges from the telomerase-mediated synthesis of the Arabidopsis-type (TTTAGGG) and vertebrate-type (TTAGGG) repeats to sequences synthesized by telomerase-independent mechanism(s) that are still to be discovered. Here we describe how the understanding of telomere biology has been advanced by methods used to isolate telomeric sequences and prove that the putative sequences isolated are indeed telomeric. We show how assays designed to prove the activity of telomerase [e.g., telomeric repeat amplification protocol (TRAP)] lead not only to an understanding of telomere structure and function, but also to the understanding of cell activity in development and in the cell cycle. We review how assays designed to reveal protein/protein and protein/nucleic acid interactions promote understanding of the structure and activities of plant telomeres. Together, the data are making significant contributions to telomere biology in general and could have medical implications.

Cell Nucleus↗

Immunological and biochemical characterization of streptococcal pyrogenic exotoxins I and J (SPE-I and SPE-J) from Streptococcus pyogenes.

Recently, we described the identification of novel streptococcal superantigens (SAgs) by mining the Streptococcus pyogenes M1 genome database at Oklahoma University. Here, we report the cloning, expression, and functional analysis of streptococcal pyrogenic exotoxin (SPE)-J and another novel SAg (SPE-I). SPE-I is most closely related to SPE-H and staphylococcal enterotoxin I, whereas SPE-J is most closely related to SPE-C. Recombinant forms of SPE-I and SPE-J were mitogenic for PBL, both reaching half maximum responses at 0.1 pg/ml. Evidence from binding studies and cell aggregation assays using a human B-lymphoblastoid cell line (LG-2) suggests that both toxins exclusively bind to the polymorphic MHC class II beta-chain in a zinc-dependent mode but not to the generic MHC class II alpha-chain. The results from analysis by light scattering indicate that SPE-J exists as a dimer in solution above concentrations of 4.0 mg/ml. Moreover, SPE-J induced a rapid homotypic aggregation of LG-2 cells, suggesting that this toxin might cross-link MHC class II molecules on the cell surface by building tetramers of the type HLA-DRbeta-SPE-J-SPE-J-HLA-DRbeta. SPE-I preferably stimulates T cells bearing the Vbeta18.1 TCR, which is not targeted by any other known SAG: SPE-J almost exclusively stimulates Vbeta2.1 T cells, a Vbeta that is targeted by several other streptococcal SAgs, suggesting a specific role for this T cell subpopulation in immune defense. Despite a primary sequence diversity of 51%, SPE-J is functionally indistinguishable from SPE-C and might play a role in streptococcal disease, which has previously been addressed to SPE-C.

Amino Acid Sequence↗

Exploring genome architecture through GOV: a WWW-based gene order visualizer.

MOTIVATION: The past decade has seen extension in the methods of sequence analysis from single gene based to analyzing multiple genes and proteins simultaneously. Consequently, there is a need for software tools that will allow mining of these enormous datasets at genome level effectively. A key challenge is to make them user-friendly, available to a larger community and integrate with public domain software without much hassle. RESULTS: A web-based interactive computational tool is described for visualization and comparison of gene order from prokaryotic and selected viral genome data. Many intriguing similarities and differences in gene order of multiple genomes can be compared and revealed. The interface facilitates easy extraction of the nucleotide sequence of the gene of interest and BLAST analysis against GenBank at NCBI to provide insights into gene functions and orthologs of the gene in other species.

Algorithms↗

Data mining and characterization of a novel pediocin-like bacteriocin system from the genome of Pediococcus pentosaceus ATCC 25745.

The genome of Pediococcus pentosaceus ATCC 25745 contains a gene cluster that resembles a regulated bacteriocin system. The gene cluster has an operon-like structure consisting of a putative pediocin-like bacteriocin gene (termed penA) and a potential immunity gene (termed peiA). Genetic determinants involved in bacteriocin transport and regulation are also found in proximity to penA and peiA but the so-called accessory gene involved in transport and the inducer gene involved in regulation are missing. Consequently, this bacterium is a poor bacteriocin producer. To analyse the potency of the putative bacteriocin operon, the two genes penA-peiA were heterologously expressed in a Lactobacillus sakei host that contains the complete apparatus for gene activation, maturation and externalization of bacteriocins. It was demonstrated that the heterologous host expressing penA and peiA produced a strong bacteriocin activity; in addition, the host became immune to its own bacteriocin, identifying the gene pair penA-peiA as a potent bacteriocin system. The novel pediocin-like bacteriocin, termed penocin A, has an isotopic mass [M+H]+ of 4684.6 Da as determined by mass spectrometry; this value corresponds well to the expected size of the mature 42 aa peptide containing a disulfide bridge. The bacteriocin is heat-stable but protease-sensitive and has a calculated pI of 9.45. Penocin A has a relatively broad inhibition spectrum, including pathogenic Listeria and Clostridium species. Immediately upstream of the regulatory genes reside some features that resemble remnants of a disrupted inducer gene. This degenerate gene was restored and shown to encode a double-glycine leader-containing peptide. Furthermore, expression of the restored gene triggered high bacteriocin production in P. pentosaceus ATCC 25745, thus confirming its role as an inducer in the pen regulon.

Amino Acid Sequence↗

[Cancer genome or the development of molecular portraits of tumors].

The rapid development of cancer genomics is due to important progresses in oncogenesis, human genome sequencing and emergence of new technologies in genome and transcriptome analysis. In this context, the aim of the French program 'Cartes d'Identites des Tumeurs--Molecular Portraits of Tumors' is to build a public data base containing a pan genome assessment of genome and transcriptome alterations in the major types of tumors as well as in relevant normal cells and experimental models. Data mining is done in the context of genome annotations and clinical and biological informations attached to the enrolled samples. The goal of the program is to define new tests useful for diagnostic procedures in clinical laboratories and new targets for biological treatments of tumors.

France↗

Data mining and genetic algorithm based gene/SNP selection.

OBJECTIVE: Genomic studies provide large volumes of data with the number of single nucleotide polymorphisms (SNPs) ranging into thousands. The analysis of SNPs permits determining relationships between genotypic and phenotypic information as well as the identification of SNPs related to a disease. The growing wealth of information and advances in biology call for the development of approaches for discovery of new knowledge. One such area is the identification of gene/SNP patterns impacting cure/drug development for various diseases. METHODS: A new approach for predicting drug effectiveness is presented. The approach is based on data mining and genetic algorithms. A global search mechanism, weighted decision tree, decision-tree-based wrapper, a correlation-based heuristic, and the identification of intersecting feature sets are employed for selecting significant genes. RESULTS: The feature selection approach has resulted in 85% reduction of number of features. The relative increase in cross-validation accuracy and specificity for the significant gene/SNP set was 10% and 3.2%, respectively. CONCLUSION: The feature selection approach was successfully applied to data sets for drug and placebo subjects. The number of features has been significantly reduced while the quality of knowledge was enhanced. The feature set intersection approach provided the most significant genes/SNPs. The results reported in the paper discuss associations among SNPs resulting in patient-specific treatment protocols.

Algorithms↗

Genome-wide genotyping in Parkinson's disease and neurologically normal controls: first stage analysis and public release of data.

BACKGROUND: Several genes underlying rare monogenic forms of Parkinson's disease have been identified over the past decade. Despite evidence for a role for genetics in sporadic Parkinson's disease, few common genetic variants have been unequivocally linked to this disorder. We sought to identify any common genetic variability exerting a large effect in risk for Parkinson's disease in a population cohort and to produce publicly available genome-wide genotype data that can be openly mined by interested researchers and readily augmented by genotyping of additional repository subjects. METHODS: We did genome-wide, single-nucleotide-polymorphism (SNP) genotyping of publicly available samples from a cohort of Parkinson's disease patients (n=267) and neurologically normal controls (n=270). More than 408,000 unique SNPs were used from the Illumina Infinium I and HumanHap300 assays. FINDINGS: We have produced around 220 million genotypes in 537 participants. This raw genotype data has been and as such is the first publicly accessible high-density SNP data outside of the International HapMap Project. We also provide here the results of genotype and allele association tests. INTERPRETATION: We generated publicly available genotype data for Parkinson's disease patients and controls so that these data can be mined and augmented by other researchers to identify common genetic variability that results in minor and moderate risk for disease.

Aged↗

Functional and comparative genomics of pathogenic bacteria.

Microarray expression profiling and the development of data-mining tools and new statistical instruments affords an unprecedented opportunity for the genome-scale study of bacterial pathogenicity. Expression profiles obtained from bacteria grown in media simulating host microenvironments yield a portrait of interacting metabolic pathways and multistage developmental programs and disclose regulatory networks. The analysis of closely related strains and species by microarray-based comparative genomics provides a measure of genetic variability within natural populations and identifies crucial differences between pathogen and commensal. In the near future, the combined use of bacterial and host microarrays to study the same infected tissue will reveal the host-pathogen dialogue in a gene-by-gene and site- and time-specific manner. This review discusses the use of microarray-based expression profiling to identify genes of pathogenic bacteria that are differentially regulated in response to host-specific signals. Additionally, the review describes the application of microarray methods to disclose differences in gene content between taxonomically related strains that vary with respect to pathogenic phenotype.

Animals↗

Discovery of the order 'Quisvirales' redefines the evolution of RNA replication and transcription in the phylum Pisuviricota.

Genome replication in positive-stranded RNA (ssRNA+) viruses is mediated by cognate enzymes, including ubiquitous RNA-dependent RNA polymerase (RdRp). In ssRNA+ viruses with multiple open reading frames (ORFs) in their genomes, replication often is accompanied by synthesis of subgenomic RNAs (transcription) for expression of 3'-proximal ORFs. In addition, all ssRNA+ viruses with genomes larger than ~7 kb encode helicases, linking helicases to RNA genome expansion. Helicases are essential ATPases that unwind nucleic acids and are classified into six recognized superfamilies (SF1-SF6). In the phylum Pisuviricota that includes important pathogens, helicases of SF1-SF3 are integrated into multi-enzyme replicase polyprotein(s) including 3C(-like) protease (3CLpro) and RdRp. Here, large-scale mining of invertebrate metatranscriptomes and targeted genome sequence assembly uncovered six spider-associated ssRNA+ viruses that, based on their conserved 3CLpro-RdRp module in replicase polyproteins, genome size (20-22 kb), and phylogeny, form a family-like cluster in a putative order, named 'Quisvirales'. Quisviruses have similar genome and replicase architectures to enveloped coronaviruses and other nidoviruses. Notably, quisviruses encode ORFs 1a and 1b with predicted -1 programmed ribosomal frameshifting elements in the ORF1a/b overlap region. Using an original mapping approach for detecting chimeric sequencing reads, we obtained evidence that 3'-proximal ORFs are expressed via 5'-coterminal, leader-containing subgenomic RNAs. This suggests that the quisvirus subgenomic RNAs are generated through discontinuous transcription-a mechanism otherwise exclusively found in nidoviruses among the many ssRNA+ virus orders that synthesize subgenomic RNAs. Striking differences between nido- and quisviruses are, however, the RdRp being the only common core ORF1b-encoded enzyme and the replacement of the nidovirus SF1 helicase by a novel superfamily helicase. This quisvirus SF7 helicase, like the Picornavirales SF3 helicase, comprises an AAA+ (ATPase-like) domain typical for ring-forming helicases and thus must play an essential role in replication. The discovery of the order 'Quisvirales' demonstrates that viruses employing large replicase polyproteins of nidovirus-like complexity and discontinuous transcription may have evolved repeatedly from an 3CLpro-RdRp-encoding ancestor.

AAA+/RecA-like ATPase↗

Long terminal repeat retrotransposons of Mus musculus.

BACKGROUND: Long terminal repeat (LTR) retrotransposons make up a large fraction of the typical mammalian genome. They comprise about 8% of the human genome and approximately 10% of the mouse genome. On account of their abundance, LTR retrotransposons are believed to hold major significance for genome structure and function. Recent advances in genome sequencing of a variety of model organisms has provided an unprecedented opportunity to evaluate better the diversity of LTR retrotransposons resident in eukaryotic genomes. RESULTS: Using a new data-mining program, LTR_STRUC, in conjunction with conventional techniques, we have mined the GenBank mouse (Mus musculus) database and the more complete Ensembl mouse dataset for LTR retrotransposons. We report here that the M. musculus genome contains at least 21 separate families of LTR retrotransposons; 13 of these families are described here for the first time. CONCLUSIONS: All families of mouse LTR retrotransposons are members of the gypsy-like superfamily of retroviral-like elements. Several different families of unrelated non-autonomous elements were identified, suggesting that the evolution of non-autonomy may be a common event. High sequence similarity between several LTR retrotransposons identified in this study and those found in distantly-related species suggests that horizontal transfer has been a significant factor in the evolution of mouse LTR retrotransposons.

Animals↗

Blondes, lost and found: representations of genes, identity, and history.

Research carried out during recent decades has revealed our genome not only to be a unique mine of information about health, disease and the human condition, but also about the origin and dispersal history of the species. In this context, the genome is simply an additional source of information about human history, epistemologically no different from other historical sources. However, media and public interpretation of genetic studies of human history are complicated by the wider connotations of genes as the determinants of hereditary features and identity. We discuss two examples of media and public fascination with the interrelated themes of history, identity and heredity, pointing out some implications of historical research using genetic data in the context of our own ongoing study of Inuit groups in Greenland and Victoria Island, Canada.

Arctic Regions↗