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Molecular Therapy : the Journal of the... Nov 2021Nucleoside-modified messenger RNA (mRNA)-lipid nanoparticles (LNPs) are the basis for the first two EUA (Emergency Use Authorization) COVID-19 vaccines. The use of...
Nucleoside-modified messenger RNA (mRNA)-lipid nanoparticles (LNPs) are the basis for the first two EUA (Emergency Use Authorization) COVID-19 vaccines. The use of nucleoside-modified mRNA as a pharmacological agent opens immense opportunities for therapeutic, prophylactic and diagnostic molecular interventions. In particular, mRNA-based drugs may specifically modulate immune cells, such as T lymphocytes, for immunotherapy of oncologic, infectious and other conditions. The key challenge, however, is that T cells are notoriously resistant to transfection by exogenous mRNA. Here, we report that conjugating CD4 antibody to LNPs enables specific targeting and mRNA interventions to CD4+ cells, including T cells. After systemic injection in mice, CD4-targeted radiolabeled mRNA-LNPs accumulated in spleen, providing ∼30-fold higher signal of reporter mRNA in T cells isolated from spleen as compared with non-targeted mRNA-LNPs. Intravenous injection of CD4-targeted LNPs loaded with Cre recombinase-encoding mRNA provided specific dose-dependent loxP-mediated genetic recombination, resulting in reporter gene expression in about 60% and 40% of CD4+ T cells in spleen and lymph nodes, respectively. T cell phenotyping showed uniform transfection of T cell subpopulations, with no variability in uptake of CD4-targeted mRNA-LNPs in naive, central memory, and effector cells. The specific and efficient targeting and transfection of mRNA to T cells established in this study provides a platform technology for immunotherapy of devastating conditions and HIV cure.
Topics: Animals; CD4-Positive T-Lymphocytes; COVID-19; COVID-19 Vaccines; Humans; Immunotherapy; Lipids; Lymph Nodes; Mice; Mice, Inbred C57BL; Nanoparticles; RNA, Messenger; Recombination, Genetic; SARS-CoV-2; Spleen; Transfection
PubMed: 34091054
DOI: 10.1016/j.ymthe.2021.06.004 -
Cold Spring Harbor Perspectives in... Oct 2014The links between recombination and replication have been appreciated for decades and it is now generally accepted that these two fundamental aspects of DNA metabolism... (Review)
Review
The links between recombination and replication have been appreciated for decades and it is now generally accepted that these two fundamental aspects of DNA metabolism are inseparable: Homologous recombination is essential for completion of DNA replication and vice versa. This review focuses on the roles that recombination enzymes play in underpinning genome duplication, aiding replication fork movement in the face of the many replisome barriers that challenge genome stability. These links have many conserved features across all domains of life, reflecting the conserved nature of the substrate for these reactions, DNA.
Topics: DNA; DNA Replication; Genomic Instability; Homologous Recombination; Models, Genetic; Recombination, Genetic
PubMed: 25341919
DOI: 10.1101/cshperspect.a016550 -
Comptes Rendus Biologies 2016Meiosis is a specialized cell division at the origin of the haploid cells that eventually develop into the gametes. It therefore lies at the heart of Mendelian heredity.... (Review)
Review
Meiosis is a specialized cell division at the origin of the haploid cells that eventually develop into the gametes. It therefore lies at the heart of Mendelian heredity. Recombination and redistribution of the homologous chromosomes arising during meiosis constitute an important source of genetic diversity, conferring to meiosis a particularly important place in the evolution and the diversification of the species. Our understanding of the molecular mechanisms governing meiotic recombination has considerably progressed these last decades, benefiting from complementary approaches led on various model species. An overview of these mechanisms will be provided as well as a discussion on the implications of these recent discoveries.
Topics: Animals; Chromosome Segregation; Chromosomes; Genetics; Humans; Meiosis; Recombination, Genetic
PubMed: 27180110
DOI: 10.1016/j.crvi.2016.04.003 -
Philosophical Transactions of the Royal... Dec 2017Recombination, the process by which DNA strands are broken and repaired, producing new combinations of alleles, occurs in nearly all multicellular organisms and has...
Recombination, the process by which DNA strands are broken and repaired, producing new combinations of alleles, occurs in nearly all multicellular organisms and has important implications for many evolutionary processes. The effects of recombination can be , as it can facilitate adaptation, but also when it breaks apart beneficial combinations of alleles, and recombination is highly between taxa, species, individuals and across the genome. Understanding how and why recombination rate varies is a major challenge in biology. Most theoretical and empirical work has been devoted to understanding the role of recombination in the evolution of sex-comparing between sexual and asexual species or populations. How recombination rate evolves and what impact this has on evolutionary processes within sexually reproducing organisms has received much less attention. This Theme Issue focusses on how and why recombination rate varies in sexual species, and aims to coalesce knowledge of the molecular mechanisms governing recombination with our understanding of the evolutionary processes driving variation in recombination within and between species. By integrating these fields, we can identify important knowledge gaps and areas for future research, and pave the way for a more comprehensive understanding of how and why recombination rate varies.
Topics: Genome; Recombination, Genetic; Reproduction
PubMed: 29109232
DOI: 10.1098/rstb.2017.0279 -
Current Biology : CB Apr 2014
Topics: Recombination, Genetic; Reproduction; Sex; Species Specificity
PubMed: 24735848
DOI: 10.1016/j.cub.2014.01.060 -
Philosophical Transactions of the Royal... Dec 2017Recombination, the exchange of DNA between maternal and paternal chromosomes during meiosis, is an essential feature of sexual reproduction in nearly all multicellular... (Review)
Review
Recombination, the exchange of DNA between maternal and paternal chromosomes during meiosis, is an essential feature of sexual reproduction in nearly all multicellular organisms. While the role of recombination in the evolution of sex has received theoretical and empirical attention, less is known about how recombination rate evolves and what influence this has on evolutionary processes within sexually reproducing organisms. Here, we explore the patterns of, and processes governing recombination in eukaryotes. We summarize patterns of variation, integrating current knowledge with an analysis of linkage map data in 353 organisms. We then discuss proximate and ultimate processes governing recombination rate variation and consider how these influence evolutionary processes. Genome-wide recombination rates (cM/Mb) can vary more than tenfold across eukaryotes, and there is large variation in the distribution of recombination events across closely related taxa, populations and individuals. We discuss how variation in rate and distribution relates to genome architecture, genetic and epigenetic mechanisms, sex, environmental perturbations and variable selective pressures. There has been great progress in determining the molecular mechanisms governing recombination, and with the continued development of new modelling and empirical approaches, there is now also great opportunity to further our understanding of how and why recombination rate varies.This article is part of the themed issue 'Evolutionary causes and consequences of recombination rate variation in sexual organisms'.
Topics: Chromosome Mapping; Eukaryota; Genetic Linkage; Genome; Recombination, Genetic
PubMed: 29109219
DOI: 10.1098/rstb.2016.0455 -
PLoS Computational Biology Nov 2022Understanding the benefits and costs of recombination under different scenarios of evolutionary adaptation remains an open problem for theoretical and experimental... (Review)
Review
Understanding the benefits and costs of recombination under different scenarios of evolutionary adaptation remains an open problem for theoretical and experimental research. In this study, we focus on finite populations evolving on neutral networks comprising viable and unfit genotypes. We provide a comprehensive overview of the effects of recombination by jointly considering different measures of evolvability and mutational robustness over a broad parameter range, such that many evolutionary regimes are covered. We find that several of these measures vary non-monotonically with the rates of mutation and recombination. Moreover, the presence of unfit genotypes that introduce inhomogeneities in the network of viable states qualitatively alters the effects of recombination. We conclude that conflicting trends induced by recombination can be explained by an emerging trade-off between evolvability on the one hand, and mutational robustness on the other. Finally, we discuss how different implementations of the recombination scheme in theoretical models can affect the observed dependence on recombination rate through a coupling between recombination and genetic drift.
Topics: Models, Genetic; Biological Evolution; Genetic Drift; Genotype; Mutation; Recombination, Genetic; Evolution, Molecular
PubMed: 36409763
DOI: 10.1371/journal.pcbi.1010710 -
FEMS Microbiology Reviews Sep 2011Lateral genetic transfer (LGT) is a major source of phenotypic innovation among bacteria. Determinants for antibiotic resistance and other adaptive traits can spread... (Review)
Review
Lateral genetic transfer (LGT) is a major source of phenotypic innovation among bacteria. Determinants for antibiotic resistance and other adaptive traits can spread rapidly, particularly by conjugative plasmids, but also phages and natural transformation. Each successive step from the uptake of foreign DNA, its genetic recombination and regulatory integration, to its establishment in the host population presents differential barriers and opportunities. The emergence of successive multidrug-resistant strains of Staphylococcus aureus illustrates the ongoing role of LGT in the combinatorial assembly of pathogens. The dynamic interplay among hosts, vectors, DNA elements, combinations of genetic determinants and environments constructs communities of genetic exchange. These relations can be abstracted as a graph, within which an exchange community might correspond to a path, transitively closed set, clique or near-clique. We provide a set-based definition, and review the features of actual genetic exchange communities (GECs), adopting first a knowledge-driven approach based on literature, and then a synoptic data-centric bioinformatic approach. GECs are diverse, but share some common features. Differential opportunity and barriers to lateral genetic transfer create bacterial communities of exchange.
Topics: Adaptation, Biological; Anti-Bacterial Agents; Bacteria; Bacterial Infections; Drug Resistance, Bacterial; Gene Transfer, Horizontal; Humans; Recombination, Genetic; Selection, Genetic
PubMed: 21223321
DOI: 10.1111/j.1574-6976.2010.00261.x -
Philosophical Transactions of the Royal... Dec 2017In species with genetic sex-determination, the chromosomes carrying the sex-determining genes have often evolved non-recombining regions and subsequently evolved the... (Review)
Review
In species with genetic sex-determination, the chromosomes carrying the sex-determining genes have often evolved non-recombining regions and subsequently evolved the full set of characteristics denoted by the term 'sex chromosomes'. These include size differences, creating chromosomal heteromorphism, and loss of gene functions from one member of the chromosome pair. Such characteristics and changes have been widely reviewed, and underlie molecular genetic approaches that can detect sex chromosome regions. This review deals mainly with the evolution of new non-recombining regions, focusing on how certain evolutionary situations select for suppressed recombination (rather than the proximate mechanisms causing suppressed recombination between sex chromosomes). Particularly important is the likely involvement of sexually antagonistic polymorphisms in genome regions closely linked to sex-determining loci. These may be responsible for the evolutionary strata of sex chromosomes that have repeatedly formed by recombination suppression evolving across large genome regions. More studies of recently evolved non-recombining sex-determining regions should help to test this hypothesis empirically, and may provide evidence about whether other situations can sometimes lead to sex-linked regions evolving. Similarities with other non-recombining genome regions are discussed briefly, to illustrate common features of the different cases, though no general properties apply to all of them.This article is part of the themed issue 'Evolutionary causes and consequences of recombination rate variation in sexual organisms'.
Topics: Biological Evolution; Evolution, Molecular; Polymorphism, Genetic; Recombination, Genetic; Sex Chromosomes
PubMed: 29109220
DOI: 10.1098/rstb.2016.0456 -
Biochemical Society Transactions Apr 2010A remarkable feature of the serine resolvases is their regulation: the wild-type enzymes will catalyse intra- but not inter-molecular recombination, can sense the... (Review)
Review
A remarkable feature of the serine resolvases is their regulation: the wild-type enzymes will catalyse intra- but not inter-molecular recombination, can sense the relative orientation of their sites and can exchange strands directionally, despite the fact that there is no net release of chemical bond energy. The key to this regulation is that they are only active within a large intertwined complex called the 'synaptosome'. Because substrate topology greatly facilitates (or, in other cases, inhibits) formation of the synaptosome, it acts as a 'topological filter'. Within the defined topology of the synaptosome, strand exchange releases supercoiling tension, providing an energy source to bias the reaction direction. The regulatory portion of this complex contains additional copies of the recombinase and sometimes other DNA-bending proteins. We are using a combination of X-ray crystallography, biochemistry and genetics to model the full synaptic complex and to understand how the regulatory portion activates the crossover-site-bound recombinases.
Topics: Animals; Bacterial Proteins; DNA; DNA Nucleotidyltransferases; Enzyme Activation; Humans; Models, Biological; Models, Molecular; Nucleic Acid Conformation; Protein Conformation; Recombinases; Recombination, Genetic; Serine
PubMed: 20298188
DOI: 10.1042/BST0380384