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Molecular characterization and biological characteristics of a highly pathogenic recombinant ALV-J strain (HUE2023) with cross-clade gp85 recombination.

Avian leukosis virus subgroup J (ALV-J) has undergone extensive diversification into phylogenetically distinct clades, yet whether recombination between these clades within the gp85 envelope glycoprotein generates variants with altered pathogenicity has received little direct investigation. A field strain (HUE2023) was recovered from breeding roosters displaying vascular tumors. The viral genome was sequenced and subjected to phylogenetic and recombination analyses. The three-dimensional structure of gp85 was predicted with AlphaFold3; electrostatic surface potentials and surface hydrophobicity were computed using the Adaptive Poisson-Boltzmann Solver and the Eisenberg hydrophobicity scale, respectively. Pathogenicity and immunosuppressive effects were assessed in Hy-Line Brown chickens. Recombination analysis revealed that HUE2023 is an inter-clade recombinant derived from Clade 1.1 (major parent: JS14NT01) and Clade 1.2 (minor parent: JS09GY3). A single-residue deletion at position 61 within receptor-binding domain 1 (RBD-1), unique to the recombinant, induced a localized conformational rearrangement that generated a concentrated electronegative surface patch and a contiguous hydrophobic pocket not observed in either parental gp85. Animal challenge showed that HUE2023 is highly pathogenic: female chickens in the high-dose group reached only 61% survival and displayed significant growth retardation (P&#x202f;<&#x202f;0.05) together with marked immunosuppression. The recombination in the RBD-1 led to local conformational rearrangement, resulting in a concentrated and negatively charged surface area as well as a continuous hydrophobic pocket, which were never present in any of the parental gp85 sequences. These results indicate that gp85 recombination across clades can yield variants with fundamentally altered receptor-binding surfaces and argue for integrating structural surveillance into ALV-J monitoring programmes.

Animals

Frequent mutations in the BIRC3 gene promote metastatic potential of nasopharyngeal carcinoma cells through the TRAF2-NF-&#x3ba;B pathway.

Nasopharyngeal carcinoma (NPC) is a head and neck cancer characterized by highly locoregionally invasive behavior attributable to the latent infection with Epstein-Barr virus (EBV) and genomic instability. It is well established that EBV-encoded oncogenic molecules actively contribute to the malignant behavior of NPC cells. However, the mechanism by which aberrant genomic alterations enable NPC cells to become aggressive remains largely unknown. In the present study, whole-exome sequencing (WES) revealed that the gene encoding the baculoviral IAP repeat-containing 3 (BIRC3) protein was frequently mutated in circulating tumor cells (CTCs) but not in paired primary tumor cells from patients with metastatic NPC. A minigene assay indicated that the c.637&#xa0;A&#xa0;>&#xa0;G mutation disrupted normal mRNA splicing, resulting in the partial deletion of Exons 2 and 3 and altered stability of BIRC3 mRNA. In vitro experiments demonstrated that ectopic expression of the BIRC3c.637A>G mutant enhanced NPC cell invasive properties, including proliferation, resistance to apoptosis, migration, and invasion. Furthermore, overexpression of wild-type BIRC3 promoted invasive characteristics in NPC cells through the TRAF2-NF-&#x3ba;B signaling axis. In summary, BIRC3 acts as a regulator of the malignant features of NPC cells. Frequent BIRC3 mutations in CTCs, such as the c.637&#xa0;A&#xa0;>&#xa0;G mutation, further enhance the metastatic potential of disseminated NPC cells by inducing aberrant alternative splicing. These findings suggest the therapeutic feasibility of targeting the BIRC3/TRAF2/NF-&#x3ba;B axis in the treatment of NPC.

Humans

Ecr positively regulates activity of the PhoQ/PhoP signalling system in Klebsiella pneumoniae.

BACKGROUND: The rising prevalence of polymyxin resistance in multidrug-resistant Klebsiella pneumoniae presents a critical situation with limited therapeutic options. METHODS: Methods Genomic sequencing of 15 clinical polymyxin-resistant K. pneumoniae strains with multidrug resistance revealed that MgrB inactivation, predominantly disrupted by insertion sequences (ISs) in the IS1, IS4, and IS5 families, was the leading cause of polymyxin resistance. Comparative transcriptomics of wild-type, &#x394;mgrB, and &#x394;mgrB&#x394;phoP were performed to elucidate the MgrB-PhoPQ regulatory network. RESULTS: This study conducted a system-wide analysis of the regulatory network and identified a species-specific PhoPQ regulon in K. pneumoniae.Beyond the classical MgrB-PhoPQ-ArnBCADTEF pathway, we identified a previously unannotated PhoPQ-regulated gene, 144 bp LN739_RS09850, encoding an Ecr homologue from Enterobacter cloacae. This protein has been reported to confer colistin heteroresistance, with the underlying mechanism not yet functionally validated. This study revealed that overexpression of Ecr homologues decreased colistin susceptibility in both K. pneumoniae and E. cloacae, but this phenotype was abolished upon phoP deletion, confirming PhoP's essential role. Consistent with this dependency, comparative transcriptomics of Ecr-overexpressing K. pneumoniae vs. control revealed significant upregulation of mgrB, phoPQ, arnBCADTE, and pmrD. Two-hybrid bacterial assays further demonstrated direct Ecr-PhoQ interaction. Electrophoretic mobility shift assay confirmed that PhoP directly binds to the ecr promoter in vitro, and a &#x3b2;-galactosidase reporter assay demonstrated that PhoP enhanced ecr promoter activity, indicating that PhoP regulates ecr expression by directly controlling its transcription. CONCLUSION: Collectively, these findings suggest that PhoP may directly activate the transcription of Ecr, with Ecr feedback activating the PhoPQ system via interaction with PhoQ, leading to induction of the arn operon and consequent polymyxin resistance.

Klebsiella pneumoniae

Generation of spCAS9 expressing human mesenchymal stem cell line to study gene function during osteoblast differentiation.

Human bone marrow-derived stromal cells (hMSCs) are a great resource for studying how genes influence cell fate and differentiation into various cell types like osteoblasts, adipocytes, and chondrocytes, among other cell types. However, genetic manipulation of primary hMSCs has been challenging due to their short lifespan and cellular senescence after limited passaging. Their low and unstable transfection efficiency also complicates gene delivery or inactivation, hindering long-term functional studies. The limited lifespan has been effectively solved by immortalizing hMSCs with telomerase reverse transcriptase (hMSCs-TERT). The use of these cells is ideal for functional studies of osteoblast and adipocyte differentiation through genetic manipulation, providing a stable and reliable model. Here, we have engineered a stable CAS9 expressing hMSC-TERT cell line (hMSC-TERTCAS9) via lentiviral transduction. The constitutive expression of spCas9 enables efficient and reproducible gene editing. We demonstrate the potential of these hMSC-TERTCAS9 cells for generating gene disruptions using plasmid delivery of guide RNAs as a fast and efficient strategy for targeted genome editing. The edited cells can be sorted and expanded as single cells to obtain homogenous clonal cell lines with mono- as well as bi-allelic gene deletions, a crucial step for producing reliable experimental results. We further validate this cell line as a powerful tool for studying gene function during hMSC proliferation and differentiation, providing 3 distinct examples of its utility. Through the generation of indels, single-cell sorting, and clonal selection, we have efficiently inactivated the vitamin D receptor and created both larger (256 nucleotides) gene disruptions in Forkhead box protein O1 and precise removals of a small genomic sequence (73 nucleotides) coding for microRNA MIR675. This novel hMSC-TERTCAS9 cell line represents a significant advancement, offering a stable, efficient, and versatile platform for advanced genetic studies, high-throughput screening, and the creation of reliable cellular disease models.

CRISPR-Cas9

Sex-dependent protective effects of microglial tumor necrosis factor on post-stroke inflammation and myelin injury.

Tumor necrosis factor (TNF) is rapidly induced after ischemic stroke, but its proposed cell-specific and sex-dependent functions during post-stroke inflammation remain insufficiently understood. Here, we investigated the role of microglia-derived TNF in the acute and subacute response to permanent middle cerebral artery occlusion (pMCAO). Tnf expression was transiently upregulated after stroke, becoming significant at 4&#xa0;h, peaking at 12-24&#xa0;h, and returning to baseline by 5&#xa0;days. In situ hybridization confirmed strong Tnf expression in the infarct and peri-infarct regions. Whole-brain transcriptomic profiling showed that global TNF deficiency reshaped the early post-ischemic response, shifting it from microglia-associated phagocytic and wound-healing pathways toward an interferon-related inflammatory signature. To define the specific contribution of microglial TNF, we used inducible Cx3cr1CreER:Tnffl/fl mice. Microglial TNF deletion had no effect on infarct volume in males at 24&#xa0;h or 5&#xa0;days after pMCAO, but significantly increased infarct size in females at both time points. In both sexes, brain TNF levels peaked at 24&#xa0;h and were significantly reduced in Cx3cr1CreER:Tnffl/fl mice, confirming microglia as a major source of early post-ischemic TNF. However, downstream consequences diverged by sex. At 5&#xa0;days, male Cx3cr1CreER:Tnffl/fl mice showed reduced microglial reactivity and 18&#xa0;kDa translocator protein (TSPO) signal, with no change in T-cell infiltration, and exhibited increased density of mature oligodendrocytes. In contrast, female Cx3cr1CreER:Tnffl/fl mice displayed enhanced microglial reactivity, increased TSPO binding, higher peri-infarct T-cell infiltration, and reduced oligodendrocyte density and myelin integrity. Together, these findings identify microglial TNF as a sex-dependent regulator of post-stroke inflammation and myelin injury.

Animals

Searching for New Genes That Cause Usher Syndrome.

PURPOSE: The purpose of this project was to identify novel Usher syndrome (USH) candidate genes from phenotyping data of 9139 knockout (KO) mouse lines. METHODS: We evaluated phenotype data for concurrent retinopathy and hearing abnormalities in single-gene KO mice generated by the International Mouse Phenotyping Consortium (IMPC). A search was performed to determine whether each gene had been previously associated with retinopathy and/or deafness in humans. Bioinformatic tools were used to predict protein interactions, molecular functions, signaling pathways, and the expression of human orthologues of candidate genes in the retina and inner ear. RESULTS: We identified 18 single-gene KO lines exhibiting hearing abnormality and retinopathy after ear and eye examinations, respectively, and/or by histopathology. The molecular functions and signaling pathways of the human orthologues of the 18 candidate genes partially overlapped with those of USH genes. Particularly, FER and DYRK1B proteins were predicted to interact with proteins encoded by known ciliopathy genes. ADIPOR1, ATP8B1, and MPDZ were associated with retinal degeneration in humans. CHSY1 and IDUA may be pathogenic causes of hearing impairment in people. Furthermore, CHSY1, CSTB, and SPRED1 were located adjacent to unsolved genetic loci related to USH. CONCLUSIONS: A screen of 9139 KO mouse lines revealed 18 candidate genes exhibiting both retinal and inner ear abnormalities consistent with the principal clinical features associated with USH. As the observed phenotypes are attributed to gene deletion in mice, these genes warrant further study to determine the causation of retinal degeneration and hearing loss in patients.

Animals

[A case of bilateral open-lip schizencephaly with West syndrome due to variant of PAFAH1B1 gene and literature review].

OBJECTIVE: To report the clinical manifestations, genetic features, diagnosis, treatment, and prognosis of a child with bilateral open-lip schizencephaly complicated by West syndrome due to a variant of PAFAH1B1 gene, and review the relevant literature. METHODS: Clinical data of a 4-month-old boy were retrospectively analyzed, and 35 previously reported cases were systematically reviewed. This study was approved by the Medical Ethics Committee of Gansu Provincial People's Hospital (Ethics No.: 2025-871). RESULTS: The 4-month-old boy presented with clustered flexor spasms, hypsarrhythmia on electroencephalography, and developmental regression. Brain magnetic resonance imaging revealed bilateral pachygyria, schizencephaly, and dysgenesis of the corpus callosum. Trio whole-exome sequencing identified a de novo heterozygous NM_000430.4: c.703_704delAG (p.Glu235Metfs*20) frameshift variant in the PAFAH1B1 gene. Sanger sequencing confirmed that neither parent carried this variant. Based on the guidelines from American College of Medical Genetics and Genomics (ACMG), the variant has met the criteria for PVS1+PS2_Moderate+PM2_Supporting, and was classified as pathogenic. After treatment with adrenocorticotropic hormone combined with vigabatrin and other antiseizure medications, the epileptic spasms were controlled and the electroencephalographic abnormalities had improved. However, global developmental delay persisted at the 12-month follow-up. Analysis of the present case and 35 previously reported cases showed that PAFAH1B1-related phenotypes were highly consistent, mainly including infantile spasms (28/36), developmental delay/intellectual disability (29/36), and abnormal brain MRI findings (30/36), predominantly cortical malformations. The reported variant types included deletions, frameshift variants, nonsense variants, missense variants, and splice-site variants. CONCLUSION: PAFAH1B1 gene variants are an important cause for cortical malformations, including schizencephaly, and may lead to secondary West syndrome. This study has systematically summarized the genotypic and phenotypic features of bilateral open-lip schizencephaly complicated by West syndrome associated with a frameshift variant of the PAFAH1B1 gene. For infants with epileptic spasms or early-onset epilepsy accompanied by structural brain abnormalities, early genetic evaluation should be performed, and antiseizure treatment should be integrated with neurodevelopmental rehabilitation to facilitate long-term management.

Humans

Gene-environment interaction between perinatal oxytocin exposure and Pten mutation shapes epigenetic reprogramming of oxytocin signaling and behavior in mice.

Synthetic oxytocin (Pitocin) is the most commonly used pharmacologic agent for induction and augmentation of labor. Beyond its uterotonic effects, oxytocin plays a critical role in neurodevelopment and social behavior. Dysregulated oxytocin signaling has been implicated in autism spectrum disorder (ASD), raising concern that perinatal exposure to exogenous oxytocin may have lasting neurodevelopmental consequences. This study aimed to determine whether offspring harboring a genetic predisposition for ASD are differentially impacted by perinatal oxytocin exposures, with a focus on long-term oxytocin signaling and autism-like behavior. Pregnant mice carrying offspring with heterozygous mutations in phosphatase and tensin homolog deleted on chromosome ten (Pten), a well-established monogenic risk factor for ASD, received continuous oxytocin versus phosphate-buffered saline (PBS) control via micro-osmotic pumps during late gestation. Wild-type (WT) offspring exposed to each treatment served as a secondary control. Adult offspring were assessed for oxytocin receptor (Oxtr) methylation in the frontal cortex and hippocampus, oxytocin expression in the hypothalamus, serum oxytocin levels, and were subject to a battery of social and anxiety-related behavior tests. Perinatal oxytocin exposure produced genotype-dependent effects in offspring. Epigenetic analyses revealed bidirectional remodeling of Oxtr methylation in the frontal cortex and hippocampus, with increased exon 1 methylation in WT mice and decreased methylation in Pten-mutant mice, resulting in significant genotype-treatment interactions. Hypothalamic oxytocin expression increased following treatment regardless of genotype, though baseline levels were higher in Pten-mutant mice. Neither oxytocin treatment nor genotype impacted long-term serum oxytocin levels. Behavioral outcomes were modest but context-specific: repetitive behaviors and cognition performance were unchanged, but oxytocin-treated Pten-mutant mice exhibited increased anxiety-like behavior alongside improved social memory. In contrast, oxytocin-treated WT mice showed reduced social novelty preference. Exploratory analyses suggested potential sex-dependent trends. Our findings support a model in which genetic susceptibility shapes the epigenetic encoding of early-life hormonal signals, thereby recalibrating oxytocin system function and downstream behavioral outcomes. Together, these data highlight the context-dependent effects of perinatal oxytocin exposure and argue against uniformly beneficial or detrimental effects, emphasizing the importance of gene-environment interactions in neurodevelopmental trajectories.

Animals

[Study of a patient with azoospermia due to variant of MOV10L1 gene].

OBJECTIVE: To explore the clinical and genotypic characteristics of a patient with Sertoli cell-only syndrome (SCOS) due to variants of MOV10L1 gene. METHODS: A 27-year-old patient with Non-obstructive azoospermia (NOA) underwent routine semen analysis. Serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), progesterone (P), estradiol (E2), prolactin (PRL), and testosterone (T) were determined by chemiluminescence assays. Peripheral blood samples were collected for G-banded karyotyping analysis. Multiplex PCR fluorescence detection was used to screen for AZF gene microdeletions. Whole exome sequencing (WES) and Sanger sequencing were performed simultaneously. Testicular biopsy tissues were subjected to Hematoxylin-Eosin (HE) staining to assess seminiferous tubule cell composition, and MOV10L1 protein expression was detected by immunohistochemical staining. Bioinformatics tools were employed to predict the pathogenicity of variants and their impact on protein structure and function. This study was approved by the Medical Ethics Committee of the Guangdong Institute of Reproductive Sciences [Ethics No.: 2023(01)]. RESULTS: The patient's two semen analyses had failed to detect any sperm. Hormone tests indicated elevated FSH (22.32 mIU/mL) and PRL (397.6 mIU/mL), while T (3.68 nmol/L) and E2 (38.32 pmol/L) were reduced. Chromosomal karyotyping revealed 46,XY, and no AZF gene deletion was detected. WES and Sanger sequencing detected compound heterozygous variants of the MOV10L1 gene, including a c.345C>A (p.C115X) nonsense variant and a c.3323C>T (p.T1108I) missense variant, with the former being unreported previously. HE staining showed only Sertoli cells in the seminiferous tubules, confirming the diagnosis of SCOS. Immunohistochemical staining revealed absent MOV10L1 protein expression in the testicular tissue. Based on the guidelines from American College of Medical Genetics and Genomics (ACMG), the c.345C>A (p.C115X) was classified as a pathogenic variant (PVS1+PM2_Supporting+PP4), while the c.3323C>T (p.T1108I) was deemed variant of uncertain significance (PM2_Supporting+PP3_Supporting+PP4). Bioinformatics analysis demonstrated that c.345C>A (p.C115X) may cause premature termination of protein translation, while c.3323C>T (p.T1108I) may disrupt the hydrophobicity of the RNA helicase domain, reducing the active pocket volume and decreasing its affinity for MILI protein. CONCLUSION: This study has diagnosed a case of SCOS due to compound heterozygous variants of the MOV10L1 gene, which also enriched its mutational spectrum.

Humans