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A method is described for generating conditional lethal mutations in essential genes in Escherichia coli. In this procedure, amber stop codons are introduced as "tagalong" mutations in the flanking DNA of a downstream antibiotic-resistance marker by lambda Red recombination. The marker is removed by expression of I-SceI homing endonuclease, leaving a markerless mutation. The mutants then depend upon expression of a suppressor transfer RNA (tRNA) for survival, which is expressed under control of the arabinose promoter on a high-copy-number plasmid.
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http://dx.doi.org/10.1007/978-1-59745-321-9_21 | DOI Listing |
Insect Sci
September 2025
Department of Entomology & Nematology, University of Florida, Gainesville, Florida.
The sterile insect technique (SIT) is a highly effective biologically-based method for the suppression of many insect pest populations. SIT efficacy could be improved by methods of male sterilization that avoid the use of irradiation that can result in diminished fitness and mating competitiveness. Alternative sterilization methods include conditional disruption of genes for male fertility, or using their sperm-specific promoters to drive the expression of genes for lethal effectors.
View Article and Find Full Text PDFCell Rep
September 2025
Shanghai Institute of Hematology, State Key Laboratory of Medical Genomics, National Research Center for Translational Medicine at Shanghai, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China; Pôle de Recherches Sino-Français en Science du Vivant et Gé
RNA helicase DDX3X is generally implicated in inflammasome activation and anti-viral responses. We characterize the common features of scattered DDX3X mutations in lymphoid cancers using molecular dynamics simulation and crystallization, thereby demonstrating their crucial role in Epstein-Barr virus (EBV) lytic gene-driven oncogenic processes. The DDX3X mutation is significantly related to impaired stimulator of interferon genes (STING)/ interferon regulatory factor 7 (IRF-7)/interferon (IFN)-α/β-mediated innate immunity, overexpression of EBV lytic gene BNLF2b, and increased formation of R-loops.
View Article and Find Full Text PDFbioRxiv
August 2025
Department of Biological Sciences, Southern Methodist University, Dallas, TX.
The leading cause of epilepsy-related mortality is sudden unexpected death in epilepsy (SUDEP), resulting from seizure-induced cardiorespiratory arrest by mechanisms that remain unresolved. Mutations in ion channel genes expressed in both brain and heart represent SUDEP risk factors because they can disrupt neural and cardiac rhythms, providing a unified explanation for seizures and lethal arrhythmias. However, the relative contributions of brain-driven mechanisms, heart-intrinsic processes, and seizures to cardiac dysfunction in epilepsy remain unclear.
View Article and Find Full Text PDFInsect Sci
August 2025
School of BioSciences, The University of Melbourne, Melbourne, Victoria, Australia.
Bactrocera tryoni, the Queensland fruit fly, is among the most damaging insect pests to the Australian horticultural industry as larvae infest ripening fruits or vegetables prior to harvest. Genetic biocontrol using Sterile Insect Technique (SIT) programs have been used to successfully suppress populations, via mass release of factory-reared sterile males that mate with wild females. Bi-sex flies are currently used for releases, although the efficiency of these control programs could be improved through using genetic sexing strains that eliminate females early during development, as they are not required for SIT.
View Article and Find Full Text PDFNature
August 2025
Genome Instability, Inflammation and Cell Death Laboratory, Institute of Biochemistry I, Centre for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany.
Conditional deletion of Caspase-8 in epidermal keratinocytes (Casp8) causes necroptosis-driven lethal dermatitis. Here, we discover that Casp8 loss leads to accumulation of cytosolic DNA responsible for the activation of a cyclic-GMP-AMP synthase (cGAS)/stimulator of interferon (IFN) gene (STING)-mediated transcriptional program. Genetic and biochemical evidence indicate that STING upregulates both Z-DNA binding protein-1 (ZBP1), and mixed lineage kinase domain-like (MLKL).
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