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Complete genome sequence and phylogenetic analysis of hepatitis B virus (HBV) isolates from patients with chronic HBV infection in Korea.

Although there is a report of high rate of hepatitis B virus (HBV) infection in South Korea, only a few entire genome sequences of HBV isolates from Korea have been reported. To obtain the complete nucleotide sequence of the Korean HBV, viral DNA was extracted from sera of Korean patients with chronic HBV infection who have not been exposed to any antiviral treatment. Complete genomic sequences were determined on three Korean HBV isolates. The entire genomic length of Korean HBV isolates, designated as KUHB84, KUHB81, and KUHB95, was 3,215 base pairs. No deletions and insertions were observed. Core promoter mutations (T1762/A1764) were detected in two isolates, KUHB84 and KUHB95. Phylogenetic analysis based on the entire genomic sequences showed that the Korean HBV isolates were genotype C and related closely to the Japanese HBV.

Amino Acid Substitution↗

Long-term follow-up of children who received rapid genomic sequencing.

PURPOSE: To explore long-term trajectories of children who received rapid genome sequencing (RGS) in intensive care settings. METHODS: We examined the electronic health records of 67 critically ill pediatric patients who received RGS 6 to 8 years ago with a collective initial diagnostic yield of 46%. RESULTS: The median length of follow-up was 6.2 years (interquartile range 4.0-7.2 years). RGS-diagnosed patients had a longer average follow-up time compared with undiagnosed patients (5.9 years vs 4.8 years, P = .026) and more subspecialty appointments per follow-up year (9.4 vs 6.9, P = .036). Mortality during the follow-up period was 9%. Patients averaged 2.1 hospital readmissions per follow-up year and 28.1 hospitalized days per follow-up year. Forty-four patients (66%) had a documented new phenotype in the electronic health records during their follow-up period. Seven patients received clinician-driven reanalysis during the follow-up period, yielding 1 new diagnosis. Systematic reanalysis of RGS performed as part of this study identified 4 new candidate diagnoses. CONCLUSION: Pediatric patients who receive RGS during intensive care unit hospitalizations continue to be high health care utilizers in subsequent years, regardless of whether RGS identified a diagnosis. Additionally, two-thirds of this cohort had a documented phenotypic change over the follow-up period, indicating dynamic clinical evolution in the years after RGS.

Humans↗

The first complete chloroplast genome sequence of a lycophyte, Huperzia lucidula (Lycopodiaceae).

We used a unique combination of techniques to sequence the first complete chloroplast genome of a lycophyte, Huperzia lucidula. This plant belongs to a significant clade hypothesized to represent the sister group to all other vascular plants. We used fluorescence-activated cell sorting (FACS) to isolate the organelles, rolling circle amplification (RCA) to amplify the genome, and shotgun sequencing to 8x depth coverage to obtain the complete chloroplast genome sequence. The genome is 154,373 bp, containing inverted repeats of 15,314 bp each, a large single-copy region of 104,088 bp, and a small single-copy region of 19,657 bp. Gene order is more similar to those of mosses, liverworts, and hornworts than to gene order for other vascular plants. For example, the Huperzia chloroplast genome possesses the bryophyte gene order for a previously characterized 30 kb inversion, thus supporting the hypothesis that lycophytes are sister to all other extant vascular plants. The lycophyte chloroplast genome data also enable a better reconstruction of the basal tracheophyte genome, which is useful for inferring relationships among bryophyte lineages. Several unique characters are observed in Huperzia, such as movement of the gene ndhF from the small single copy region into the inverted repeat. We present several analyses of evolutionary relationships among land plants by using nucleotide data, inferred amino acid sequences, and by comparing gene arrangements from chloroplast genomes. The results, while still tentative pending the large number of chloroplast genomes from other key lineages that are soon to be sequenced, are intriguing in themselves, and contribute to a growing comparative database of genomic and morphological data across the green plants.

Chromosome Mapping↗

A genomic sequencing protocol that yields a positive display of 5-methylcytosine residues in individual DNA strands.

The modulation of DNA-protein interactions by methylation of protein-binding sites in DNA and the occurrence in genomic imprinting, X chromosome inactivation, and fragile X syndrome of different methylation patterns in DNA of different chromosomal origin have underlined the need to establish methylation patterns in individual strands of particular genomic sequences. We report a genomic sequencing method that provides positive identification of 5-methylcytosine residues and yields strand-specific sequences of individual molecules in genomic DNA. The method utilizes bisulfite-induced modification of genomic DNA, under conditions whereby cytosine is converted to uracil, but 5-methylcytosine remains nonreactive. The sequence under investigation is then amplified by PCR with two sets of strand-specific primers to yield a pair of fragments, one from each strand, in which all uracil and thymine residues have been amplified as thymine and only 5-methylcytosine residues have been amplified as cytosine. The PCR products can be sequenced directly to provide a strand-specific average sequence for the population of molecules or can be cloned and sequenced to provide methylation maps of single DNA molecules. We tested the method by defining the methylation status within single DNA strands of two closely spaced CpG dinucleotides in the promoter of the human kininogen gene. During the analysis, we encountered in sperm DNA an unusual methylation pattern, which suggests that the high methylation level of single-copy sequences in sperm may be locally modulated by binding of protein factors in germ-line cells.

5-Methylcytosine↗

A 1463 gene cattle-human comparative map with anchor points defined by human genome sequence coordinates.

A second-generation 5000 rad radiation hybrid (RH) map of the cattle genome was constructed primarily using cattle ESTs that were targeted to gaps in the existing cattle-human comparative map, as well as to sparsely populated map intervals. A total of 870 targeted markers were added, bringing the number of markers mapped on the RH(5000) panel to 1913. Of these, 1463 have significant BLASTN hits (E < e(-5)) against the human genome sequence. A cattle-human comparative map was created using human genome sequence coordinates of the paired orthologs. One-hundred and ninety-five conserved segments (defined by two or more genes) were identified between the cattle and human genomes, of which 31 are newly discovered and 34 were extended singletons on the first-generation map. The new map represents an improvement of 20% genome-wide comparative coverage compared with the first-generation map. Analysis of gene content within human genome regions where there are gaps in the comparative map revealed gaps with both significantly greater and significantly lower gene content. The new, more detailed cattle-human comparative map provides an improved resource for the analysis of mammalian chromosome evolution, the identification of candidate genes for economically important traits, and for proper alignment of sequence contigs on cattle chromosomes.

Animals↗

Computer tool FUNSITE for analysis of eukaryotic regulatory genomic sequences.

We present the computer tool FUNSITE for description and analysis of regulatory sequences of eukaryotic genomes. The tool consists of the following main parts: 1) An integrated database for genomic regulatory sequences. The integrated database was designed on the basis of the databases TRANSFAC (Wingender 1994) and TRRD (Kel et al. 1995) that are currently under development. The following functions are performed: i) linkage to the EMBL database; ii) preparing samples of definite types of functional sites with their flanking sequences; iii) preparing samples of promoter sequences; iv) preparing samples of transcription factors classified with regard to structural and functional features of DNA binding and activating domains, functional families of the factors, their tissue specificity and other functional features; v) access to data on mutual disposition of cis-elements within the regulatory regions. 2) The second component of FUNSITE tool is the set of programs for analysis of the structural organization of regulatory sequences: i) Program for revealing of potential transcription factors binding sites based on their consensi; ii) program for revealing of the potential binding sites using homology search with nucleotide sequences of real binding sites; iii) program for analysis of oligonucleotide context features which are characteristic of flank sequences of the binding sites; iv) program for design of recognition method for the functional sites based on generalized weight matrix; v) program for revealing potential composite elements. The results of analysis of the promoter sequences of eukaryotic genes with the FUNSITE are presented, too.

Amino Acid Sequence↗

The cell surface of Lactobacillus reuteri ATCC 55730 highlighted by identification of 126 extracellular proteins from the genome sequence.

Bioinformatical analyses of a draft genome sequence of the commensal bacterium Lactobacillus reuteri ATCC 55730 revealed 126 genes encoding putative extracellular proteins. The function, localization and distribution in bacterial species were predicted. Interestingly, few proteins possessed LPXTG motifs or C-terminal transmembrane anchors. Instead eight proteins were putatively anchored by GW repeats and several secreted proteins were likely to be re-associated to the surface. The majority of the extracellular proteins were widely distributed, i.e., found universally or in gram-positive bacteria, but 24 were only detected in L. reuteri. Further, the number of transporters was lower, while the number of enzyme was higher than in related species.

Amino Acid Motifs↗

An effective approach for analyzing "prefinished" genomic sequence data.

Ongoing efforts to sequence the human genome are already generating large amounts of data, with substantial increases anticipated over the next few years. In most cases, a shotgun sequencing strategy is being used, which rapidly yields most of the primary sequence in incompletely assembled sequence contigs ("prefinished" sequence) and more slowly produces the final, completely assembled sequence ("finished" sequence). Thus, in general, prefinished sequence is produced in excess of finished sequence, and this trend is certain to continue and even accelerate over the next few years. Even at a prefinished stage, genomic sequence represents a rich source of important biological information that is of great interest to many investigators. However, analyzing such data is a challenging and daunting task, both because of its sheer volume and because it can change on a day-by-day basis. To facilitate the discovery and characterization of genes and other important elements within prefinished sequence, we have developed an analytical strategy and system that uses readily available software tools in new combinations. Implementation of this strategy for the analysis of prefinished sequence data from human chromosome 7 has demonstrated that this is a convenient, inexpensive, and extensible solution to the problem of analyzing the large amounts of preliminary data being produced by large-scale sequencing efforts. Our approach is accessible to any investigator who wishes to assimilate additional information about particular sequence data en route to developing richer annotations of a finished sequence.

Algorithms↗

Complete mitochondrial genome sequence of Urechis caupo, a representative of the phylum Echiura.

BACKGROUND: Mitochondria contain small genomes that are physically separate from those of nuclei. Their comparison serves as a model system for understanding the processes of genome evolution. Although hundreds of these genome sequences have been reported, the taxonomic sampling is highly biased toward vertebrates and arthropods, with many whole phyla remaining unstudied. This is the first description of a complete mitochondrial genome sequence of a representative of the phylum Echiura, that of the fat innkeeper worm, Urechis caupo. RESULTS: This mtDNA is 15,113 nts in length and 62% A+T. It contains the 37 genes that are typical for animal mtDNAs in an arrangement somewhat similar to that of annelid worms. All genes are encoded by the same DNA strand which is rich in A and C relative to the opposite strand. Codons ending with the dinucleotide GG are more frequent than would be expected from apparent mutational biases. The largest non-coding region is only 282 nts long, is 71% A+T, and has potential for secondary structures. CONCLUSIONS: Urechis caupo mtDNA shares many features with those of the few studied annelids, including the common usage of ATG start codons, unusual among animal mtDNAs, as well as gene arrangements, tRNA structures, and codon usage biases.

Amino Acid Sequence↗

The e subunit gene of murine F1F0-ATP synthase. Genomic sequence, chromosomal mapping, and diet regulation.

Genomic sequences encoding murine Lfm1, whose predicted protein sequence is 96% and 98% similar to bovine and rat F1F0-ATP synthase e subunits (respectively), have been amplified from BALB/cByJ DNA, cloned, and sequenced. The 1.1-kilobase gene has 3 introns and 4 exons, and its coding sequence differs by two nucleotides compared to the previously published BALB/cHnn Lfm1 cDNA sequence. A PstI restriction site polymorphism in intron 2 between C57BL/6J and Mus spretus was used to map this gene to Chromosome 5 near D5Mit9. Related sequences were mapped on Chromosomes 8, 11, and 2 unlinked loci on Chromosome 2 using Southern blot analyses with the 1. 1-kilobase gene as probe. Previous studies from this laboratory indicated that the Lfm1/e subunit was regulated by the level of dietary fat and carbohydrate. Northern hybridization analyses demonstrated that e subunit mRNA abundance showed statistically significant differences (p < 0.025) between hearts of BALB/c mice fed 3% and those fed 20% corn oil for 2 weeks and in liver (p < 0. 05) from the same animals. Significant differences were also observed in hepatic and heart mRNA expression at different times after eating in animals subjected to a fast/refeed regimen. The implications of the high degree of sequence similarity to the e subunit for rat and bovine F1F0-ATP synthase and its regulation by diet are discussed.

Animals↗

Divergence of the hyperthermophilic archaea Pyrococcus furiosus and P. horikoshii inferred from complete genomic sequences.

Divergence of the hyperthermophilic Archaea, Pyrococcus furiosus and Pyrococcus horikoshii, was assessed by analysis of complete genomic sequences of both species. The average nucleotide identity between the genomic sequences is 70-75% within ORFs. The P. furiosus genome (1.908 mbp) is 170 kbp larger than the P. horikoshii genome (1.738 mbp) and the latter displays significant deletions in coding regions, including the trp, his, aro, leu-ile-val, arg, pro, cys, thr, and mal operons. P. horikoshii is auxotrophic for tryptophan and histidine and is unable to utilize maltose, unlike P. furiosus. In addition, the genomes differ considerably in gene order, displaying displacements and inversions. Six allelic intein sites are common to both Pyrococcus genomes, and two intein insertions occur in each species and not the other. The bacteria-like methylated chemotaxis proteins form a functional group in P. horikoshii, but are absent in P. furiosus. Two paralogous families of ferredoxin oxidoreductases provide evidence of gene duplication preceding the divergence of the Pyrococcus species.

Archaeal Proteins↗

Detection of DNA sequence polymorphisms by enzymatic amplification and direct genomic sequencing.

The discovery of RFLPs and their utilization as genetic markers has revolutionized research in human molecular genetics. However, only a fraction of the DNA sequence polymorphisms in the human genome affect the length of a restriction fragment and hence result in an RFLP. Polymorphisms that are not detected as RFLPs are typically passed over in the screening process though they represent a potentially important source of informative genetic markers. We have used a rapid method for the detection of naturally occurring DNA sequence variations that is based on enzymatic amplification and direct sequencing of genomic DNA. This approach can detect essentially all useful sequence variations within the region screened. We demonstrate the feasibility of the technique by applying it to the human retinoblastoma susceptibility locus. We screened 3,712 bp of genomic DNA from each of nine individuals and found four DNA sequence polymorphisms. At least one of these DNA sequence polymorphisms was informative in each of three families with hereditary retinoblastoma that were not informative with any of the known RFLPs at this locus. We believe that direct sequencing is a reasonable alternative to other methods of screening for DNA sequence polymorphisms and that it represents a step forward for obtaining informative markers at well-characterized loci that have been minimally informative in the past.

Base Sequence↗

Identification of functional clusters of transcription factor binding motifs in genome sequences: the MSCAN algorithm.

MOTIVATION: The identification of regulatory control regions within genomes is a major challenge. Studies have demonstrated that regulating regions can be described as locally dense clusters or modules of cis-acting transcription factor binding sites (TFBS). For well-described biological contexts, it is possible to train predictive algorithms to discern novel modules in genome sequences. However, utility of module detection methods has been severely limited by insufficient training data. For only a few tissues can one obtain sufficient numbers of literature-derived regulatory modules. RESULTS: We present a novel method, MSCAN, that circumvents the training data problem by measuring the statistical significance of any non-overlapping combination of TFBS in a window. Given a set of transcription factor binding profiles, a significance threshold, and a genomic sequence, MSCAN returns putative regulatory regions. We assess performance on two curated collections of regulatory regions; one each for tissue-specific expression in liver and skeletal muscle cells. The efficiency of MSCAN allows for predictive screens of entire genomes.

Algorithms↗

DNA Data Bank of Japan at work on genome sequence data.

We at the DNA Data Bank of Japan (DDBJ) (http://www.ddbj.nig.ac.jp) have recently begun receiving, processing and releasing EST and genome sequence data submitted by various Japanese genome projects. The data include those for human, Arabidopsis thaliana, rice, nematode, Synechocystis sp. and Escherichia coli. Since the quantity of data is very large, we organized teams to conduct preliminary discussions with project teams about data submission and handling for release to the public. We also developed a mass submission tool to cope with a large quantity of data. In addition, to provide genome data on WWW, we developed a genome information system using Java. This system (http://mol.genes.nig.ac.jp/ecoli/) can in theory be used for any genome sequence data. These activities will facilitate processing of large quantities of EST and genome data.

Animals↗

Nucleic acid amplification testing and genome sequencing for WHO priority viruses in Africa: a scoping review.

Emerging viruses continue to pose serious public health threats across Africa, with recurrent outbreaks exposing gaps in diagnostics and surveillance systems. Nucleic acid amplification tests (NAATs) and genome sequencing are increasingly important for diagnostics and outbreak responses; however, their routine implementation is fragmented. This scoping review examines NAATs and genome sequencing technologies for viral detection and surveillance in Africa from 2019 to 2024, mapped to the 2024 updated WHO R&D Blueprint for Epidemics pathogen priority list. We identified 117 studies from 34 African countries reporting applications across 20 virus families, including ten designated as priorities by WHO. PCR-based assays were the most frequently reported NAATs. Illumina platforms predominated sequencing, and Oxford Nanopore Technologies were commonly used in outbreak investigations. Genome sequencing applied to priority viruses was largely reactive. NAAT-capable mobile laboratories were reported in 13 countries. Our findings underscore the need for proactive integration of NAATs into diagnostic and surveillance systems to strengthen decentralised testing, sustain genomic surveillance beyond outbreak periods, and improve early detection and preparedness for viral threats.

Journal Article↗

Synaptotagmin gene content of the sequenced genomes.

BACKGROUND: Synaptotagmins exist as a large gene family in mammals. There is much interest in the function of certain family members which act crucially in the regulated synaptic vesicle exocytosis required for efficient neurotransmission. Knowledge of the functions of other family members is relatively poor and the presence of Synaptotagmin genes in plants indicates a role for the family as a whole which is wider than neurotransmission. Identification of the Synaptotagmin genes within completely sequenced genomes can provide the entire Synaptotagmin gene complement of each sequenced organism. Defining the detailed structures of all the Synaptotagmin genes and their encoded products can provide a useful resource for functional studies and a deeper understanding of the evolution of the gene family. The current rapid increase in the number of sequenced genomes from different branches of the tree of life, together with the public deposition of evolutionarily diverse transcript sequences make such studies worthwhile. RESULTS: I have compiled a detailed list of the Synaptotagmin genes of Caenorhabditis, Anopheles, Drosophila, Ciona, Danio, Fugu, Mus, Homo, Arabidopsis and Oryza by examining genomic and transcript sequences from public sequence databases together with some transcript sequences obtained by cDNA library screening and RT-PCR. I have compared all of the genes and investigated the relationship between plant Synaptotagmins and their non-Synaptotagmin counterparts. CONCLUSIONS: I have identified and compared 98 Synaptotagmin genes from 10 sequenced genomes. Detailed comparison of transcript sequences reveals abundant and complex variation in Synaptotagmin gene expression and indicates the presence of Synaptotagmin genes in all animals and land plants. Amino acid sequence comparisons indicate patterns of conservation and diversity in function. Phylogenetic analysis shows the origin of Synaptotagmins in multicellular eukaryotes and their great diversification in animals. Synaptotagmins occur in land plants and animals in combinations of 4-16 in different species. The detailed delineation of the Synaptotagmin genes presented here, will allow easier identification of Synaptotagmins in future. Since the functional roles of many of these genes are unknown, this gene collection provides a useful resource for future studies.

Alternative Splicing↗

A novel porcine gene, alpha-1-antichymotrypsin 2 (SERPINA3-2): sequence, genomic organization, polymorphism and mapping.

A novel porcine gene, alpha-1-antichymotrypsin 2 (SERPINA3-2), a member of the serpin superfamily, was isolated from a porcine genomic library and sequenced. The genomic organization of the approximately 9.0 kb gene was determined on the basis of the porcine liver cDNA of SERPINA3-1 and SERPINA3-2, and comprises five exons and four introns. The coding sequence of SERPINA3-2 shares 86% identity with the paralogue, SERPINA3-1. Porcine SERPINA3-2 was found to be an orthologue of human SERPINA3 (71% identity of the coding sequences) and both genes have a similar genomic organization. Polymorphisms were found in intron 4 of the porcine gene using polymerase chain reaction-restriction fragment length polymorphism. The gene was mapped by linkage analysis and radiation hybrid mapping to the distal end of chromosome 7q, to the gene cluster of the protease inhibitors including PI1 (SERPINA1), PI2, PI3, PI4 (apparently paralogues of SERPINA3), and PO1A and PO1B. SERPINA3-2 is the first porcine serpin gene whose genomic organization has been determined.

Amino Acid Sequence↗

Genomic sequence analysis of the 238-kb swine segment with a cluster of TRIM and olfactory receptor genes located, but with no class I genes, at the distal end of the SLA class I region.

Continuous genomic sequence has been previously determined for the swine leukocyte antigen (SLA) class I region from the TNF gene cluster at the border between the major histocompatibility complex (MHC) class III and class I regions to the UBD gene at the telomeric end of the classical class I gene cluster (SLA-1 to SLA-5, SLA-9, SLA-11). To complete the genomic sequence of the entire SLA class I genomic region, we have analyzed the genomic sequences of two BAC clones carrying a continuous 237,633-bp-long segment spanning from the TRIM15 gene to the UBD gene located on the telomeric side of the classical SLA class I gene cluster. Fifteen non-class I genes, including the zinc finger and the tripartite motif (TRIM) ring-finger-related family genes and olfactory receptor genes, were identified in the 238-kilobase (kb) segment, and their location in the segment was similar to their apparent human homologs. In contrast, a human segment (alpha block) spanning about 375 kb from the gene ETF1P1 and from the HLA-J to HLA-F genes was absent from the 238-kb swine segment. We conclude that the gene organization of the MHC non-class I genes located in the telomeric side of the classical SLA class I gene cluster is remarkably similar between the swine and the human segments, although the swine lacks a 375-kb segment corresponding to the human alpha block.

Amino Acids↗