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PubMed1981

Site-specific inversion sequence of the herpes simplex virus genome: domain and structural features.

The genome of herpes simplex virus-1 consists of two covalently linked components, L and S, that invert relative to each other. The L and S components consist of unique DNA sequences bracketed by inverted repeats. The inverted repeats of the L component are designated ab and b' a' and those of the S component are designated a' c' and ca. The number of a sequences at the termini and at the L-S component junction varies from one to several copies. Insertion into the middle of the L component of a DNA fragment consisting of 156 base pairs (bp) of the b sequence, an entire a sequence of 501 bp, and 618 bp of the c sequence created a new site through which additional inversions in the genome occurred. Comparison of the nucleotide sequences of DNA fragments containing one and two a sequences defined the domain of the a sequence. The single a sequence consists of two 20-bp direct repeats (designated as DR1) bracketing a region that contains 19 tandem direct repeats of a 12-bp sequence (DR2) adjacent to three direct repeats of a 37-bp sequence (DR4), in addition to short stretches of unique sequences. The fragment with two tandem a sequences contained three copies of DR1-i.e., the intervening DR1 was shared by the two a sequences. Furthermore, one a sequence contained 22 copies of DR2 and two copies of DR4 whereas the second a sequence contained 19 copies of DR2 and two copies of DR4. These observations suggest that (i) amplification of the number of terminal and internal a sequences is the consequence of intramolecular or intermolecular recombination through DR1, (ii) the number of copies of DR2 and DR4 within the a sequence is not fixed and may vary as a consequence of unequal crossing over or slippage, and (iii) inversion results from intramolecular recombination between terminal and inverted a sequences.

Animals↗

PubMed2006

Selection of target sites for mobile DNA integration in the human genome.

DNA sequences from retroviruses, retrotransposons, DNA transposons, and parvoviruses can all become integrated into the human genome. Accumulation of such sequences accounts for at least 40% of our genome today. These integrating elements are also of interest as gene-delivery vectors for human gene therapy. Here we present a comprehensive bioinformatic analysis of integration targeting by HIV, MLV, ASLV, SFV, L1, SB, and AAV. We used a mathematical method which allowed annotation of each base pair in the human genome for its likelihood of hosting an integration event by each type of element, taking advantage of more than 200 types of genomic annotation. This bioinformatic resource documents a wealth of new associations between genomic features and integration targeting. The study also revealed that the length of genomic intervals analyzed strongly affected the conclusions drawn--thus, answering the question "What genomic features affect integration?" requires carefully specifying the length scale of interest.

Binding Sites↗

PubMed1999

Primary structure and features of the genome of the Lactobacillus gasseri temperate bacteriophage (phi)adh.

The complete DNA sequence of the Lactobacillus (Lb.) gasseri temperate phage (phi)adh was determined. The linear and double-stranded genome consists of 43.785bp with a G+C content of 35. 3% and 3' protruding cohesive ends of 12nt. Sixty-two possible ORFs were identified. On the basis of homology comparisons, some of them could be assigned to possible functions, such as a helicase, a nucleic acid polymerase and a protease. In a non-coding area of the (phi)adh genome, structural features of a potential replication origin were detected. After subcloning, this region was functional as a replicon in Lb. gasseri and Lactococcus lactis. N-terminal aa sequencing and electron microscopic analysis of intact and defective phage particles enabled the identification of two capsid protein genes. One of their products, the major head protein, seems to be processed on the posttranslational level.

Amino Acid Sequence↗

PubMed2002

Complete genome structure of the thermophilic cyanobacterium Thermosynechococcus elongatus BP-1.

The entire genome of a thermophilic unicellular cyanobacterium, Thermosynechococcus elongatus BP-1, was sequenced. The genome consisted of a circular chromosome 2,593,857 bp long, and no plasmid was detected. A total of 2475 potential protein-encoding genes, one set of rRNA genes, 42 tRNA genes representing 42 tRNA species and 4 genes for small structural RNAs were assigned to the chromosome by similarity search and computer prediction. The translated products of 56% of the potential protein-encoding genes showed sequence similarity to experimentally identified and predicted proteins of known function, and the products of 34% of these genes showed sequence similarity to the translated products of hypothetical genes. The remaining 10% lacked significant similarity to genes for predicted proteins in the public DNA databases. Sixty-three percent of the T. elongatus genes showed significant sequence similarity to those of both Synechocystis sp. PCC 6803 and Anabaena sp. PCC 7120, while 22% of the genes were unique to this species, indicating a high degree of divergence of the gene information among cyanobacterial strains. The lack of genes for typical fatty acid desaturases and the presence of more genes for heat-shock proteins in comparison with other mesophilic cyanobacteria may be genomic features of thermophilic strains. A remarkable feature of the genome is the presence of 28 copies of group II introns, 8 of which contained a presumptive gene for maturase/reverse transcriptase. A trace of genome rearrangement mediated by the group II introns was also observed.

Cyanobacteria↗

PubMed2004

The genome of canarypox virus.

Here we present the genomic sequence, with analysis, of a canarypox virus (CNPV). The 365-kbp CNPV genome contains 328 potential genes in a central region and in 6.5-kbp inverted terminal repeats. Comparison with the previously characterized fowlpox virus (FWPV) genome revealed avipoxvirus-specific genomic features, including large genomic rearrangements relative to other chordopoxviruses and novel cellular homologues and gene families. CNPV also contains many genomic differences with FWPV, including over 75 kbp of additional sequence, 39 genes lacking FWPV homologues, and an average of 47% amino acid divergence between homologues. Differences occur primarily in terminal and, notably, localized internal genomic regions and suggest significant genomic diversity among avipoxviruses. Divergent regions contain gene families, which overall comprise over 49% of the CNPV genome and include genes encoding 51 proteins containing ankyrin repeats, 26 N1R/p28-like proteins, and potential immunomodulatory proteins, including those similar to transforming growth factor beta and beta-nerve growth factor. CNPV genes lacking homologues in FWPV encode proteins similar to ubiquitin, interleukin-10-like proteins, tumor necrosis factor receptor, PIR1 RNA phosphatase, thioredoxin binding protein, MyD116 domain proteins, circovirus Rep proteins, and the nucleotide metabolism proteins thymidylate kinase and ribonucleotide reductase small subunit. These data reveal genomic differences likely affecting differences in avipoxvirus virulence and host range, and they will likely be useful for the design of improved vaccine vectors.

Animals↗

PubMed2003

GeneViTo: visualizing gene-product functional and structural features in genomic datasets.

BACKGROUND: The availability of increasing amounts of sequence data from completely sequenced genomes boosts the development of new computational methods for automated genome annotation and comparative genomics. Therefore, there is a need for tools that facilitate the visualization of raw data and results produced by bioinformatics analysis, providing new means for interactive genome exploration. Visual inspection can be used as a basis to assess the quality of various analysis algorithms and to aid in-depth genomic studies. RESULTS: GeneViTo is a JAVA-based computer application that serves as a workbench for genome-wide analysis through visual interaction. The application deals with various experimental information concerning both DNA and protein sequences (derived from public sequence databases or proprietary data sources) and meta-data obtained by various prediction algorithms, classification schemes or user-defined features. Interaction with a Graphical User Interface (GUI) allows easy extraction of genomic and proteomic data referring to the sequence itself, sequence features, or general structural and functional features. Emphasis is laid on the potential comparison between annotation and prediction data in order to offer a supplement to the provided information, especially in cases of "poor" annotation, or an evaluation of available predictions. Moreover, desired information can be output in high quality JPEG image files for further elaboration and scientific use. A compilation of properly formatted GeneViTo input data for demonstration is available to interested readers for two completely sequenced prokaryotes, Chlamydia trachomatis and Methanococcus jannaschii. CONCLUSIONS: GeneViTo offers an inspectional view of genomic functional elements, concerning data stemming both from database annotation and analysis tools for an overall analysis of existing genomes. The application is compatible with Linux or Windows ME-2000-XP operating systems, provided that the appropriate Java Runtime Environment is already installed in the system.

Bacterial Proton-Translocating ATPases↗

PubMed2003

Gene discovery in the Entamoeba invadens genome.

Entamoeba invadens, a parasite of reptiles, is a model for the study of encystation by the human enteric pathogen Entamoeba histolytica, because E. invadens form cysts in axenic culture. With approximately 0.5-fold sequence coverage of the genome, we were able to get insights into E. invadens gene and genome features. Overall, the E. invadens genome displays many of the features that are emerging from ongoing genome sequencing efforts in E. histolytica. At the nucleotide level the E. invadens genome has on average 60% sequence identity with that of E. histolytica. The presence of introns in E. invadens was predicted with similar consensus (GTTTGT em leader A/TAG) sequences to those identified in E. histolytica and Entamoeba dispar. Sequences highly repeated in the genome of E. histolytica (rRNAs, tRNAs, CXXC-rich proteins, and Leu-rich repeat proteins) were found to be highly repeated in the E. invadens genome. Numerous proteins homologous to those implicated in amoebic virulence, (Gal/GalNAc lectins, amoebapores, and cysteine proteinases) and drug resistance (p-glycoproteins) were identified. Homologs of proteins involved in cell cycle, vesicular trafficking and signal transduction were identified, which may be involved in en/excystation and cell growth of E. invadens. Finally, multiple copies of a number of E. invadens genes coding for predicted enzymes involved in core metabolism and the targets of anti-amoebic drugs were identified.

Amino Acid Sequence↗

PubMed2006

Features and genomic origins of matrix cell adhesion molecules-1 and -2 expressed by fibroblasts of human aortic adventitial origin.

Precursor mRNAs for proteins that we have called matrix cell adhesion molecules-1 and -2 (Mat-CAM-1 and Mat-CAM-2) were cloned from fibroblasts cultured from a specimen of human abdominal aorta. Both protein sequences have the unusual feature that there is an immunoglobulin kappa (Igkappa)-like domain at the N terminus and they are glycine/proline rich in the C-terminal domain. Antibodies were raised in rabbit against peptides synthesized for a specific unique sequence of Mat-CAM-1 and Mat-CAM-2, respectively (not detected in any other proteins referenced in GenBank). Both antibodies were immunoreactive with adventitial microfibrils of the aorta and some additional arteries. Mat-CAM-1 was detected in the common/internal iliac arteries, but it was not detected in the external iliac artery. Conversely, Mat-CAM-2 was conspicuous in the external iliac artery, but not the common/internal iliac arteries. Thus, these proteins show features of site-specific expression within the arterial tree. Computerized searches show that the genomic origins of Mat-CAM-1 and -2 are in the so-called nasopharnygocarcinoma (NPC) gene on chromosome 2, which is a putative oncogene. Expression of the two different gene products from the same genomic sequence requires shifts of reading frame. Further studies will be required to determine whether these proteins are prototypes for a larger family of tissue-specific matrix proteins arising from alternative transcriptions of the same genomic sequence.

Amino Acid Sequence↗

PubMed2026

Complete telomere-to-telomere genome assembly of Guazuma ulmifolia uncovers evolutionary mechanisms, drought adaptation, and flavonoid biosynthesis.

The first T2T reference genome of Guazuma ulmifolia is reported, which serves as a core genomic resource for stress adaptation research and stress-tolerant breeding in cacao wild relatives. Climate change, particularly increased incidence of drought, poses a major threat to food security. Understanding the genomic basis of environmental adaptation in crop wild relatives can provide valuable resources for improving stress resilience. Guazuma ulmifolia, a wild relative of Theobroma cacao with important ecological and medicinal value, lacks high-quality reference genomic resources. Here, we report the first telomere-to-telomere (T2T) chromosome-level genome assembly of G. ulmifolia, with a genome size of 311.31 Mb, contig N50 of 35.19 Mb, and 98.70% BUSCO completeness. Repetitive sequences constitute 27.43% of the G. ulmifolia genome, with LTR retrotransposons as the predominant class. Comparative genomic analyses revealed that genome-size variation among Malvaceae species is associated with differences in polyploidization history and TE dynamics. Ancestral karyotype reconstruction identified five lineage-specific chromosome fusion events distinguishing G. ulmifolia from T. cacao. Comparative analyses further identified tandem duplication-associated expansion of stress-related LEA and GST gene families, suggesting potential genomic features associated with stress responses. Flavonoid biosynthesis genes were largely conserved in copy number but showed tissue-specific expression patterns, providing candidate genes for investigating secondary metabolism. Together, this study establishes a high-quality T2T genome resource for exploring genome evolution, chromosome organization, and stress-related genomic features in Malvaceae.

Genome, Plant↗

PubMed1991

Hepatitis E virus genome. Molecular features, expression of immunoreactive proteins and sequence divergence.

The strategy for molecular cloning of hepatitis E virus (HEV), the major etiologic agent of enterically-transmitted non-A, non-B hepatitis, is briefly described. The organization of the HEV genome is discussed and compared to those of two other vertebrate viruses that contain single-stranded, positive-sense, polyadenylated RNA genomes with three overlapping ORFs. Serologic cross-reactivity of expressed proteins and genetic divergence of HEV isolates are also described within the context of sequence variation, type-common epitopes, and type-specific epitopes.

Cloning, Molecular↗

PubMed2000

Pea embryonic tissues show common responses to the replication of a wide range of viruses.

The response of pea embryonic tissues to the replication of a range of different viruses was investigated using in situ hybridization to analyze changes in the expression of two host genes, heat shock protein 70 (hsp70) and lipoxygenase (lox1). Excised pea embryos were infected using microprojectile bombardment with a nonseed transmissible strain of Pea seed-borne mosaic potyvirus, or with Pea early browning tobravirus (PEBV), White Clover mosaic potexvirus, or Beet curly top geminivirus. Collectively, these examples represent families of viruses with differing genomic features, differing numbers of genomic components and differing replication strategies. In all cases, there was an induction of hsp70 associated with virus replication and, in most cases, a downregulation of lox1. Hence, either each virus has a direct inducer of these common responses or the induction is indirectly the result of a generic feature of virus infection. By exploiting the bipartite nature of the PEBV genome, the coat protein gene and genes involved in vector transmission were excluded as potential inducers.

Cotyledon↗

PubMed2026

Penalized Cumulative Probability Model for a Continuous Outcome Subject to Detection Limits.

Mixed-type outcome data occur when the outcome variable's distribution is a mixture of both continuous and discrete ordinal variables. Such mixed-type outcomes are common in biomedical, psychological, and the health sciences, particularly for variables having either a detection or quantitation limit. When interest lies in identifying a combination of genomic features associated with a mixed-type outcome, any method used would require a variable selection strategy for high-dimensional data. Unfortunately, few variable selection methods exist for modeling a mixed-type outcome when the covariate space is high dimensional. This study develops a high-dimensional penalized cumulative probability model (CPM), to allow for the identification of genomic features associated with mixed-type outcome of interest. We demonstrated how such model may be estimated using the iterative penalization procedure-the generalized monotone incremental forward stagewise (GMIFS) algorithm. The Model-X knockoffs procedure was combined with the estimation algorithm to control the false discovery rates (FDR) when performing variable selection. Through extensive simulation studies, our penalized CPM was shown to outperform alternative methods in terms of controlled variable selection performance by achieving high statistical power with the FDR being controlled at the target level. We demonstrate the utility of our method by applying it to predict estimated glomeruli filtration rate (eGFR) in kidney transplant recipients at 24 months post-transplant using baseline gene expression data as predictors. Our CPM model identified five genes associated with this mixed-type outcome which have important links to renal disease, which may provide prognostic guidance for kidney transplantation recipients.

Models, Statistical↗

PubMed2026

Bridging-driven condensation by eukaryotic SMC complexes is a conserved feature of genome organization.

The Structural Maintenance of Chromosome (SMC) protein family plays a central role in higher-order genome organization through ATP-dependent DNA loop extrusion by cohesin and condensin and other processes. Whether these activities fully account for the complexity of chromosome architecture remains unknown. Here, we uncover a conserved ATP-independent mechanism of chromatin condensation by SMC complexes, occurring via biomolecular condensation. Using single-molecule fluorescence imaging, we show that a variety of SMCs form dynamic DNA-bound condensates that exhibit key features of biomolecular condensates, including droplet coalescence, fluorescence recovery after photobleaching, and rapid exchange with free SMC complexes. Atomic force microscopy analysis of human cohesin-DNA assemblies reveals DNA-length-dependent clustering, providing evidence for bridging-driven condensation. Analyses of in vivo super-resolution imaging and high-throughput chromosome conformation capture (Hi-C) data indicate that these condensates form chromatin-associated clusters with multi-loop structures. Together, our results establish that SMC complexes employ ATP-independent phase condensation as well as ATP-dependent activities to shape genome architecture. This work reveals a broadly conserved principle of chromosomal organization across eukaryotes.

Chromosomal Proteins, Non-Histone↗

PubMed2026

Associations of TILs and genomic alterations in HER2+ early breast cancer.

This study investigated the associations between tumor-infiltrating lymphocytes (TILs), genomic features, and prognosis in HER2+ early breast cancer (EBC) patients receiving adjuvant trastuzumab. We retrospectively analyzed 864 HER2+ EBC patients from Shanghai Ruijin Hospital (2009-2017). The optimal threshold of TILs for predicting disease-free survival (DFS) and overall survival (OS) was explored. Whole-exome sequencing (WES) on 261 tumors assessed the mutational profiles, tumor mutational burden (TMB), and copy number alteration (CNA). Associations between these genomic features, TIL levels, and prognosis were further evaluated. TILs showed a right-skewed distribution (median: 15%, IQR: 1-30%), and higher TIL levels were significantly associated with hormone receptor negativity and high histologic grade (P < 0.001). A 15% TIL threshold optimally predicted prognosis, with low-TIL (≤15%, 63.0%) patients showing inferior DFS (HR: 1.63, P = 0.009) and OS (HR: 2.12, P = 0.037). WES identified frequent mutations in TP53 (62.8%), PIK3CA (34.5%), and BRCA2 (9.6%). A higher TIL density was observed in TP53-wild-type, low-TMB or low-CNA tumors (P < 0.05). PIK3CA mutations conferred a significant DFS advantage. Integrating TIL level with PIK3CA or BRCA2 mutational status yielded distinct DFS trajectories (log-rank P = 0.023 and 0.040, respectively); patients with both high TIL levels and either PIK3CA or BRCA2 mutations had the most favorable outcomes. Stromal TILs at a 15% cutoff provide robust prognostic information in trastuzumab-treated HER2+ EBC. Integrating TIL levels with PIK3CA or BRCA2 mutational status enables refined risk stratification, offering a practical framework for personalized treatment decisions.

Humans↗

PubMed2025

Chikungunya virus in Thailand (2020-2023): Epidemiology, clinical features, and genomic insights.

Chikungunya virus (CHIKV) caused significant outbreaks in Thailand during 2008-2009 and 2018-2020. Despite the COVID-19 pandemic, CHIKV continued to circulate; however, data on its epidemiological, clinical, and genetic characteristics during and after this period remains limited. This study investigated CHIKV infections in Thailand from March 2020 to December 2023. Serum samples (n = 1,264) were collected from patients with suspected CHIKV infection at 14 hospitals across five provinces in central, eastern, and northeastern Thailand. Samples were tested by RT-qPCR and IgM fluorescence immunoassay. CHIKV infection was confirmed in 50.5% (638/1,264) of cases. Infections occurred across all age groups, with the highest prevalence among individuals aged ≥56 years. Clinical symptoms significantly associated with infection included myalgia, arthralgia, rash, and conjunctivitis. Rash was more frequently in individuals aged ≤15 years and was significantly associated with lower viral loads. Arthralgia was more common among older adults and was linked to later illness onset. Myalgia was least frequently reported in younger patients. Thirty-eight complete coding sequences of our Thai CHIKV strains were analyzed in phylogenetic and time-scaled trees alongside 186 global strains and 109 ECSA-IOL strains from GenBank, respectively. Genome analysis revealed that CHIKV strains circulating in Thailand during 2020-2023 belonged to the East/Central/South African-Indian Ocean lineage (ECSA-IOL). These strains did not evolve from earlier ECSA-IOL variants that carried the E1-A226V mutation, which was previously detected in Thailand. Instead, all isolates carried E1-K211E and E2-V264A, along with E1-226A, likely introduced from the Indian subcontinent around 2016-2017. This introduction triggered a major outbreak between late 2018 and 2020, followed by sustained transmission. The 2020-2023 Thai strains exhibited high genetic similarity to those from neighboring countries, with multiple nonsynonymous mutations suggesting ongoing viral adaptation. Understanding CHIKV epidemiology, clinical features, and evolution supports improved surveillance, diagnostics, and public health interventions.

Humans↗

PubMed2000

Evolution and phylogenetic information content of mitochondrial genomic structural features illustrated with acrodont lizards.

DNA sequences from 195 squamate reptiles indicate that mitochondrial gene order is the most reliable phylogenetic character establishing monophyly of acrodont lizards and of the snake families Boidae, Colubridae, and Viperidae. Gene order shows no evidence of evolutionary parallelisms or reversals in these taxa. Derived secondary structures of mitochondrial tRNAs also prove to be useful phylogenetic characters showing no reversals. Parallelisms for secondary structures of tRNAs are restricted to deep lineages that are separated by at least 200 million years of independent evolution. Presence of a stem-and-loop structure between the genes encoding tRNA(Asn) and tRNA(Cys), where the replication origin for light-strand synthesis is typically located in vertebrate mitochondrial genomes, is found to undergo at least three and possibly as many as seven evolutionary shifts, most likely parallel losses. This character is therefore a less desirable phylogenetic marker than the other structural changes examined. Sequencing regions that contain multiple genes, including tRNA genes, may be preferable to the common practice of obtaining single-gene fragments for phylogenetic inference because it permits observation of major structural changes in the mitochondrial genome. Such characters may occasionally provide phylogenetic information on relatively short internal branches for which base substitutional changes are expected to be relatively uninformative.

Animals↗

PubMed2003

Unique and conserved features of genome and proteome of SARS-coronavirus, an early split-off from the coronavirus group 2 lineage.

The genome organization and expression strategy of the newly identified severe acute respiratory syndrome coronavirus (SARS-CoV) were predicted using recently published genome sequences. Fourteen putative open reading frames were identified, 12 of which were predicted to be expressed from a nested set of eight subgenomic mRNAs. The synthesis of these mRNAs in SARS-CoV-infected cells was confirmed experimentally. The 4382- and 7073 amino acid residue SARS-CoV replicase polyproteins are predicted to be cleaved into 16 subunits by two viral proteinases (bringing the total number of SARS-CoV proteins to 28). A phylogenetic analysis of the replicase gene, using a distantly related torovirus as an outgroup, demonstrated that, despite a number of unique features, SARS-CoV is most closely related to group 2 coronaviruses. Distant homologs of cellular RNA processing enzymes were identified in group 2 coronaviruses, with four of them being conserved in SARS-CoV. These newly recognized viral enzymes place the mechanism of coronavirus RNA synthesis in a completely new perspective. Furthermore, together with previously described viral enzymes, they will be important targets for the design of antiviral strategies aimed at controlling the further spread of SARS-CoV.

Amino Acid Sequence↗

PubMed1991

Some unusual members of the family Pasteurellaceae isolated from human sources--phenotypic features and genomic relationships.

Twelve human isolates exhibiting the properties of the family Pasteurellaceae but phenotypically deviating from established species, or resembling species of animal origin that are only rarely reported to occur in human materials, were checked for their identities by DNA-DNA hybridization. The collection consisted of one strain of Actinobacillus lignieresii, two strains of Actinobacillus hominis (mannose-positive), two hitherto undescribed Actinobacillus or Actinobacillus-like species, [Pasteurella] haemolytica biovar T, CDC group HB-5 (initially oxidase and indole-negative), a new species in the [Haemophilus] aphrophilus [Haemophilus] segnis group, a new sucrose-negative and gas-producing Pasteurella-like species, and three strains of Bisgaard's Pasteurella-like taxon 16. Some diagnostically useful features of these unusual human Pasteurellaceae are described.

Animals↗