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At least 163 records · Page 9Linked to original sources

Human adult T-cell leukemia virus: complete nucleotide sequence of the provirus genome integrated in leukemia cell DNA.

Human retrovirus adult T-cell leukemia virus (ATLV) has been shown to be closely associated with human adult T-cell leukemia (ATL) [Yoshida, M., Miyoshi, I. & Hinuma, Y. (1982) Proc. Natl. Acad. Sci. USA 79, 2031-2035]. The provirus of ATLV integrated in DNA of leukemia T cells from a patient with ATL was molecularly cloned and the complete nucleotide sequence of 9,032 bases of the proviral genome was determined. The provirus DNA contains two long terminal repeats (LTRs) consisting of 755 bases, one at each end, which are flanked by a 6-base direct repeat of the cellular DNA sequence. The nucleotides in the LTR could be arranged into a unique secondary structure, which could explain transcriptional termination within the 3' LTR but not in the 5' LTR. The nucleotide sequence of the provirus contains three large open reading frames, which are capable of coding for proteins of 48,000, 99,000, and 54,000 daltons. The three open frames are in this order from the 5' end of the viral genome and the predicted 48,000-dalton polypeptide is a precursor of gag proteins, because it has an identical amino acid sequence to that of the NH2 terminus of human T-cell leukemia virus (HTLV) p24. The open frames coding for 99,000- and 54,000-dalton polypeptides are thought to be the pol and env genes, respectively. On the 3' side of these three open frames, the ATLV sequence has four smaller open frames in various phases; these frames may code for 10,000-, 11,000-, 12,000-, and 27,000-dalton polypeptides. Although one or some of these open frames could be the transforming gene of this virus, in preliminary analysis, DNA of this region has no homology with the normal human genome.

Adult↗

Limitations of serial cloning in mammals: unresolved donor-cell genomic integrity challenges broad claims of cloning limits.

Wakayama et al. describe an extraordinary 20-year serial cloning study in mice, concluding that serial cloning in mammals is ultimately limited by the accumulation of genetic anomalies. However, their whole-genome sequencing (WGS) analysis characterized selected cloned animals but did not include matched genomic profiling of the corresponding cumulus cell (CC)-donor mice, the source CC populations, or developmental stages. Because each reconstructed embryo originated from a single CC nucleus and re-cloned animals were used to advance the lineage, pre-existing somatic variation could have entered the lineage and subsequently been propagated. Consequently, variants detected in later generations cannot be assigned definitively to pre-existing donor-cell mosaicism, donor-cell handling, somatic cell nuclear transfer manipulation, or early embryogenesis. Thus, the observed decline cannot be attributed exclusively to genetic lesions arising during repeated cloning, but the unresolved genomic status of the lineage-founding donor cells remains a plausible but unproven contributor. The study therefore demonstrates the transmission and propagation of genetic lesions through serial cloning more directly than it establishes that all initiating lesions arose because of repeated cloning. Paired genomic profiling of donor-cell populations, embryos, and offspring would help resolve the origins of accumulated genetic lesions and determine whether donor-cell screening could extend serial cloning.

Animals↗

Integrated Genomic and Proteomic Analysis Reveals T-B Lymphocyte Signatures in the MYCN Driven "Immune Desert" of Specific Neuroblastoma Subtypes.

AIMS: This study aims to systematically dissect how MYCN amplification shapes the immunosuppressive tumor microenvironment (TME) in high-risk neuroblastoma, elucidating key mechanisms underlying immune evasion. METHODS: We performed an integrated multi-omics analysis of bulk RNA-seq (n = 721), single-cell RNA-seq (n = 9), proteomic data (n = 49) and spatial transcriptomics (Visium, with external validation in melanoma). Analyses included unsupervised clustering, cell-cell communication inference, transcriptional regulatory network reconstruction, and spatial proximity assessment to map the immune landscape. RESULTS: A distinct molecular subtype (Class C), defined by MYCN amplification and poor prognosis, exhibited a comprehensive "immune desert" phenotype characterized by low immune scores and minimal leukocyte infiltration. Single-cell analysis confirmed significant depletion of T and B lymphocytes within the Class C TME. Dysregulated transcriptional networks were identified, including upregulation of REL and EOMES in T cells-with EOMES potentially driving exhaustion via regulation of Transient Receptor Potential (TRP) genes, and REL inhibition enhancing cytotoxic function in vitro. A unique immunosuppressive B-cell subset (B7) engaged in enhanced crosstalk with exhausted T cells and harbored a MYC-centered network linked to cell cycle dysregulation and poor survival. Spatial transcriptomics revealed significant proximity between B7-active regions and Treg/exhaustion-enriched areas, externally validated in melanoma. Proteomic data validated elevated REL expression in MYCN-amplified tumors. CONCLUSION: This work delineates the immunosuppressive architecture of MYCN-driven neuroblastoma, revealing novel regulatory nodes within specific lymphocyte compartments. Integrating single-cell, spatial, and proteomic evidence, we propose REL inhibition as a therapeutic candidate, the EOMES/TRP axis as a bioinformatically supported hypothesis, and the B7/MYC hub as a hypothesis supported by transcriptomic and spatial evidence.

Humans↗

An integrative genomics approach to infer causal associations between gene expression and disease.

A key goal of biomedical research is to elucidate the complex network of gene interactions underlying complex traits such as common human diseases. Here we detail a multistep procedure for identifying potential key drivers of complex traits that integrates DNA-variation and gene-expression data with other complex trait data in segregating mouse populations. Ordering gene expression traits relative to one another and relative to other complex traits is achieved by systematically testing whether variations in DNA that lead to variations in relative transcript abundances statistically support an independent, causative or reactive function relative to the complex traits under consideration. We show that this approach can predict transcriptional responses to single gene-perturbation experiments using gene-expression data in the context of a segregating mouse population. We also demonstrate the utility of this approach by identifying and experimentally validating the involvement of three new genes in susceptibility to obesity.

11-beta-Hydroxysteroid Dehydrogenase Type 1↗

Integrated Genomics and Transcriptomics Reveal Stable Resistance Loci and Candidate Genes for Powdery Mildew in Wheat.

Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), poses a substantial threat to global wheat production. Enhancing resistance through molecular breeding necessitates a comprehensive understanding of its genetic and molecular underpinnings. This study leveraged a 2-year phenotypic evaluation of 283 diverse wheat accessions combined with genome-wide association studies (GWAS) to pinpoint stable quantitative trait loci for powdery mildew resistance. We identified 52 robust resistance loci across the wheat genome, including seven novel loci consistently detected across four environments. Comparative transcriptome profiling of resistant and susceptible wheat lines revealed 95 differentially expressed genes, predominantly enriched in defense response, signal transduction, and transcription regulation pathways. By integrating the GWAS and transcriptomic data, we precisely identified three compelling candidate genes (TaPIP5K, TaPKG, and TaORR6) on chromosome 2A, which are implicated in cell wall reinforcement, jasmonic acid signaling, and reactive oxygen species scavenging, respectively. Further validation using expression analysis corroborated their pivotal roles in resistance. Our findings provide a rich repository of validated genetic markers, promising candidate genes, and superior resistant germplasms, offering critical resources to accelerate targeted molecular breeding efforts for durable powdery mildew resistance in wheat.

Blumeria graminis f. sp. tritici↗

Systematic identification of human mitochondrial disease genes through integrative genomics.

The majority of inherited mitochondrial disorders are due to mutations not in the mitochondrial genome (mtDNA) but rather in the nuclear genes encoding proteins targeted to this organelle. Elucidation of the molecular basis for these disorders is limited because only half of the estimated 1,500 mitochondrial proteins have been identified. To systematically expand this catalog, we experimentally and computationally generated eight genome-scale data sets, each designed to provide clues as to mitochondrial localization: targeting sequence prediction, protein domain enrichment, presence of cis-regulatory motifs, yeast homology, ancestry, tandem-mass spectrometry, coexpression and transcriptional induction during mitochondrial biogenesis. Through an integrated analysis we expand the collection to 1,080 genes, which includes 368 novel predictions with a 10% estimated false prediction rate. By combining this expanded inventory with genetic intervals linked to disease, we have identified candidate genes for eight mitochondrial disorders, leading to the discovery of mutations in MPV17 that result in hepatic mtDNA depletion syndrome. The integrative approach promises to better define the role of mitochondria in both rare and common human diseases.

Base Sequence↗

Mariner (Mos1) transposase and genomic integration of foreign gene sequences in Bombyx mori cells.

Widespread occurrence in insects and the capacity to transpose in the absence of host-derived factors means that mariner-like elements are considered to be attractive candidates for the development of a universal insect genetic transformation system. Here we show that the Mos1 mariner element of Drosophila mauritiana is capable of mediating excision and transposition events in a silkmoth (Bombyx mori) derived tissue culture cell line (Bm5 cells). Plasmid rescue assays, in combination with Southern hybridization and polymerase chain reaction (PCR) analyses, confirm that the Mos1 transposase can mediate excision of DNA sequences, inserted between terminally repeated sequences recognized by the transposase, and integration into the chromosomal DNA of the Bm5 cells. In addition to chromosomal integration events, inter- and intraplasmid transposition and target element excision events were also detected. Approximately 50% of the plasmids recovered from plasmid rescue assays were found to contain the 'signature' of Mos1-specific excision and/or integration events, indicating that the mariner transposase functions efficiently in the Bombyx cells. Because mariner-induced excision and integration events are strictly dependent on the presence of a co-transfected Mos1 transposase expression vector, it is clear that the multiple copies of endogenous mariner-like elements (Bmmar1) that exist in the Bombyx genome are neither functional nor do they interfere with the efficiency of the transposition process. Thus, the Mos1 element and, probably, mariner elements, in general, hold great promise for the development of genetic transformation systems for lepidopteran insects.

Animals↗

Integrated Genomic and Epigenomic Analysis Reveals Epigenetic Plasticity in Disease Progression and Multidrug Resistance in Multiple Myeloma.

UNLABELLED: Multiple myeloma is marked by recurrent cytogenetic abnormalities and mutations that accumulate as the disease progresses. In this study, we sought to elucidate the transitions driving tumorigenesis and therapy resistance in multiple myeloma using a unique cohort of nearly 900 patients spanning premalignant to late-stage refractory multiple myeloma, comprehensively characterized at molecular and clinical levels. Waves of epigenetic dysregulation drove these critical transitions. In this paradigm, genomic and cytogenetic events unlocked epigenetic plasticity, reshaping multiple myeloma cell biology to evade tumor microenvironment constraints and therapeutic pressures. Functional perturbation studies in an isogenic proteasome inhibitor-resistant cell line model demonstrated enhanced reliance on transcriptional cofactors, supporting a mechanistic link between chromatin plasticity and therapy adaptation. Collectively, these findings support a unifying framework in which genomic heterogeneity unlocks gene regulatory plasticity, enabling plasma cells (PC) to evade microenvironmental constraints and therapeutic pressure. These results provide a mechanistic explanation for sequential relapse without new genomic alterations and nominate epigenetic plasticity-mediated PC adaptation as a therapeutic vulnerability in the heterogeneous genetic background of multiple myeloma. SIGNIFICANCE: Assembly and analysis of a multiple myeloma cohort spanning the continuum from premalignant to late relapse that integrates bulk transcriptomics with single-cell multiomic data provides insights into disease progression and epigenetic plasticity.

Multiple Myeloma↗

Functions of poly(ADP-ribose) polymerase (PARP) in DNA repair, genomic integrity and cell death.

Poly(ADP-ribose) polymerase (PARP) is responsible for post-translational modification of proteins in the response to numerous endogenous and environmental genotoxic agents. PARP and poly(ADP-ribosyl)ation are proposed to be important for the regulation of many cellular processes such as DNA repair, cell death, chromatin functions and genomic stability. Activation of PARP is one of the early DNA damage responses, among other DNA sensing molecules, such as DNA-PK, ATM and p53. The generation and characterization of PARP deficient mouse models have been instrumental in defining the biological role of the molecule and its involvement in the pathogenesis of various diseases including diabetes, stroke, Parkinson disease, general inflammation as well as tumorigenesis, and have, therefore, provided information for the development of pharmaceutical strategies for the treatment of diseases.

Animals↗

Saccharomyces cerevisiae Rrm3p DNA helicase promotes genome integrity by preventing replication fork stalling: viability of rrm3 cells requires the intra-S-phase checkpoint and fork restart activities.

Rrm3p is a 5'-to-3' DNA helicase that helps replication forks traverse protein-DNA complexes. Its absence leads to increased fork stalling and breakage at over 1,000 specific sites located throughout the Saccharomyces cerevisiae genome. To understand the mechanisms that respond to and repair rrm3-dependent lesions, we carried out a candidate gene deletion analysis to identify genes whose mutation conferred slow growth or lethality on rrm3 cells. Based on synthetic phenotypes, the intra-S-phase checkpoint, the SRS2 inhibitor of recombination, the SGS1/TOP3 replication fork restart pathway, and the MRE11/RAD50/XRS2 (MRX) complex were critical for viability of rrm3 cells. DNA damage checkpoint and homologous recombination genes were important for normal growth of rrm3 cells. However, the MUS81/MMS4 replication fork restart pathway did not affect growth of rrm3 cells. These data suggest a model in which the stalled and broken forks generated in rrm3 cells activate a checkpoint response that provides time for fork repair and restart. Stalled forks are converted by a Rad51p-mediated process to intermediates that are resolved by Sgs1p/Top3p. The rrm3 system provides a unique opportunity to learn the fate of forks whose progress is impaired by natural impediments rather than by exogenous DNA damage.

Cell Division↗

Integrating genomics into health information systems.

OBJECTIVE: To outline the main issues related to the impact of the data generated by the Human Genome Project on health information systems. A major challenge for medical informatics is identified, consisting of adapting traditional systems to new genetic-based diagnostic and therapeutic tools. METHODS: Reviewing and analysing the different health information levels from an organisational complexity point of view. A model is proposed to explain the interactions between health informatics, bioinformatics and molecular medicine. RESULTS: We suggest a new framework that integrates genetic data into health information systems. Using this model, new topics for future research and development are identified. CONCLUSIONS: We are witnessing the birth of a new era (post-genomics). In this era technological advancements in genomics offer new opportunities for clinical applications. Medical informaticians should play an important role in this new endeavour.

Databases, Genetic↗

Integrative Genomic and Functional Investigation of the Multi-Layered Genetic Architecture Between Anorexia Nervosa and Bone Loss.

OBJECTIVE: Bone loss is a severe and often irreversible complication of anorexia nervosa (AN), yet the genetic mechanisms underlying this comorbidity remain underexplored. This study focuses on constructing a comprehensive genetic architecture between AN and estimated calcaneal bone mineral density (eBMD). METHOD: We applied an integrative framework incorporating genetic correlation, pleiotropic association, and causal inference across single-variant, multi-variant, and gene expression levels. Functional validation was conducted in vitro to investigate the biological role of the key candidate gene. RESULTS: Local genetic correlation analysis identified significant signals at 8p21.2 and 10q26.3, despite the lack of significant global correlation. Mendelian randomization analysis pointed to a suggestive negative causal effect of genetically predisposed AN on eBMD. Extensive pleiotropic signals were detected, particularly at 3p21.31 and 10q26.3, loci enriched with genes associated with both traits. Notably, we identified a novel pleiotropic signal near NCAM1 at 11q23.2, which was supported by multi-layered genetic evidence and confirmed through in vitro functional experiments. NCAM1, a well-established neural-associated gene, promoted osteoclastic differentiation and bone resorption when overexpressed in osteoclast precursor cells, indicating that NCAM1 possesses distinct functional roles in both neural and skeletal tissues. DISCUSSION: This study constructs a comprehensive genetic architecture underlying AN and eBMD and highlights NCAM1 as a key pleiotropic gene.

anorexia nervosa↗

Building an application framework for integrative genomics.

The accelerated pace of biological research and the current availability of whole-genome data sets provides significant new sources of functional insight. We designed an architecture and framework for software to query and explore such data in an orderly and iterative fashion. The architecture is intended to provide an extensible platform for developing web based bioinformatics applications and to offer a flexible and end-user-extensible software environment to explore and integrate disparate biological data sources. This will enable the user to explore existing relationships and discover new functional relationships among these data.

Computational Biology↗

The sirtuins hst3 and Hst4p preserve genome integrity by controlling histone h3 lysine 56 deacetylation.

BACKGROUND: Acetylation of histone H3 lysine 56 (K56Ac) occurs transiently in newly synthesized H3 during passage through S phase and is removed in G2. However, the physiologic roles and effectors of K56Ac turnover are unknown. RESULTS: The sirtuins Hst3p and, to a lesser extent, Hst4p maintain low levels of K56Ac outside of S phase. In hst3 hst4 mutants, K56 hyperacetylation nears 100%. Residues corresponding to the nicotinamide binding pocket of Sir2p are essential for Hst3p function, and H3 K56 deacetylation is inhibited by nicotinamide in vivo. Rapid inactivation of Hst3/Hst4p prior to S phase elevates K56Ac to 50% in G2, suggesting that K56-acetylated nucleosomes are assembled genome-wide during replication. Inducible expression of Hst3p in G1 or G2 triggers deacetylation of mature chromatin. Cells lacking Hst3/Hst4p exhibit many phenotypes: spontaneous DNA damage, chromosome loss, thermosensitivity, and acute sensitivity to genotoxic agents. These phenotypes are suppressed by mutation of histone H3 K56 into a nonacetylatable residue or by loss of K56Ac in cells lacking the histone chaperone Asf1. CONCLUSIONS: Our results underscore the critical importance of Hst3/Hst4p in controlling histone H3 K56Ac and thereby maintaining chromosome integrity.

Acetylation↗

Molecular cloning of feline leukemia provirus genomes integrated in the feline large granular lymphoma cells.

Feline leukemia virus (FeLV) is a horizontally transmitted agent of the domestic cat which is known to be associated with wide spectrum of diseases of the hematopoietic system. In the present study, proviral DNAs of FeLV proviruses were examined in the tumor cells of natural killer cell lineage which is very rare in cats. In the chromosomal DNA of the tumor cells, 5 distinct bands corresponding to exogenous FeLV provirus genomes were detected by digestion with EcoRI which does not cut most FeLV isolates. Five clones of pLC1, pLC2, pLC3, pLC4, and pLC5 obtained from the 5 respective bands were analysed by restriction endonuclease mapping and Southern blot hybridization using gene-specific probes of FeLV. The results have clearly demonstrated that pLC4 and pLC5 contained large deletions in the pol and part of gag regions, while the full-length proviruses could be observed in pLC1 and pLC2. Furthermore, pLC3 contained part of a variant FeLV genome having an EcoRI site in its gag region. The molecular clones of defective and variant FeLV in this study may be useful for the further examination of tumorigenesis of large granular lymphoma in the cat.

Animals↗