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Background: The toxin-antitoxin (TA) system plays a vital role in the virulence and pathogenicity of Mycobacterium tuberculosis (M. tuberculosis). However, the regulatory mechanisms and the impact of gene mutations on M. tuberculosis transmission remain poorly understood. Objective: To investigate the influence of gene mutations in the toxin-antitoxin system on M. tuberculosis transmission dynamics. Method: We performed whole-genome sequencing on the analyzed strains of M. tuberculosis. The genes associated with the toxin-antitoxin system were obtained from the National Center for Biotechnology Information (NCBI) Gene database. Mutations correlating with enhanced transmission within the genes were identified by using random forest, gradient boosting decision tree, and generalized linear mixed models. Results: A total of 13,518 M. tuberculosis isolates were analyzed, with 42.29% (n = 5,717) found to be part of genomic clusters. Lineage 4 accounted for the majority of isolates (n = 6488, 48%), followed by lineage 2 (n = 5133, 37.97%). 23 single nucleotide polymorphisms (SNPs) showed a positive correlation with clustering, including vapB1 G34A, vapB24 A76C, vapB2 T171C, mazF2 C85T, mazE2 G104A, vapB31 T112C, relB T226A, vapB11 C54T, mazE5 T344C, vapB14 A29G, parE1 (C103T, C88T), and parD1 C134T. Six SNPs, including vapB6 A29C, vapB31 T112C, parD1 C134T, vapB37 G205C, Rv2653c A80C, and vapB22 C167T, were associated with transmission clades across different countries. Notably, our findings highlighted the positive association of vapB6 A29C, vapB31 T112C, parD1 C134T, vapB37 G205C, vapB19 C188T, and Rv2653c A80C with transmission clades across diverse regions. Furthermore, our analysis identified 32 SNPs that exhibited significant associations with clade size. Conclusion: Our study presents potential associations between mutations in genes related to the toxin-antitoxin system and the transmission dynamics of M. tuberculosis. However, it is important to acknowledge the presence of confounding factors and limitations in our study. Further research is required to establish causation and assess the functional significance of these mutations. These findings provide a foundation for future investigations and the formulation of strategies aimed at controlling TB transmission. [ABSTRACT FROM AUTHOR]

Background: TIM-1, a member of the T cell immunoglobulin and mucin domain (TIM) gene family was implicated as an asthma susceptibility gene in previous studies. TIM-1 is selectively expressed on activated CD4+ T cells and its expression is sustained preferentially on T helper type 2 (Th2) cells, which suggests that TIM-1 is associated with T cell differentiation and the development of Th2-biased immune response. Methods: In order to evaluate the effects of the promoter polymorphism in the TIM-1 gene on asthma susceptibility in a Chinese Han population, 2 promoter polymorphisms, –416G>C and –1454G>A, from 2 alternative promoter regions, were genotyped in 409 unrelated asthma patients and 305 healthy controls by using polymerase chain reaction and restriction fragment length polymorphism. Also, we analyzed the functional significance of –416G>C using the luciferase reporter gene assay. Results: We found that –416G>C was associated with asthma susceptibility in our study population (χ2 = 9.88, p = 0.002, odds ratio 1.41, 95% confidence interval 1.14–1.75). No statistically significant difference in the distribution of genotype and allele frequency of the –1454G>A site was observed. The –416G>C substitution increased the transcriptional activity of the TIM-1 gene. Conclusion: Our findings suggest that the –416G>C variation site in the human TIM-1 promoter region is associated with asthma susceptibility in a Chinese Han population. Copyright © 2007 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]