The Identification and Gene Mapping of Spotted Leaf Mutant spl43 in Rice.

Our study investigates the genetic mechanisms underlying the spotted leaf phenotype in rice, focusing on the spl43 mutant. This mutant is characterized by persistent reddish-brown leaf spots from the seedling stage to maturity, leading to extensive leaf necrosis. Using map-based cloning, we localized the responsible locus to a 330 Kb region on chromosome 2. We identified LOC_Os02g56000, named OsRPT5A, as the causative gene. A point mutation in OsRPT5A, substituting valine for glutamic acid, was identified as the critical factor for the phenotype. Functional complementation and the generation of CRISPR/Cas9-mediated knockout lines in the IR64 background confirmed the central role of OsRPT5A in controlling this trait. The qPCR results from different parts of the rice plant revealed that OsRPT5A is constitutively expressed across various tissues, with its subcellular localization unaffected by the mutation. Notably, we observed an abnormal accumulation of reactive oxygen species (ROS) in spl43 mutants by examining the physiological indexes of leaves, suggesting a disruption in the ROS system. Complementation studies indicated OsRPT5A's involvement in ROS homeostasis and catalase activity regulation. Moreover, the spl43 mutant exhibited enhanced resistance to Xanthomonas oryzae pv. oryzae (Xoo), highlighting OsRPT5A's role in rice pathogen resistance mechanisms. Overall, our results suggest that OsRPT5A plays a critical role in regulating ROS homeostasis and enhancing pathogen resistance in rice.

IGFBP2 upregulates ZEB1 expression and promotes hepatocellular carcinoma progression through NF-κB signaling pathway.

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most lethal cancers owing to the high metastasis rate. The molecular mechanism underlying HCC progression remains unclear. AIMS: We aimed to explore the function and mechanism of action of insulin-like growth factor binding protein 2 (IGFBP2) in HCC. METHODS: Expression of IGFBP2 was evaluated with western blotting and reverse transcription polymerase chain reaction (RT-PCR). Loss- and gain-function assays were conducted to evaluate the effects of IGFBP2 on HCC cell proliferation, migration, and invasion. Signaling pathways were screened with a dual-fluorescein reporting system, and levels of epithelial and mesenchymal markers were measured after altering IGFBP2 expression. Cell fractionation analysis was conducted to evaluate the nuclear translocation of p65. RESULTS: IGFBP2 expression was upregulated in HCC tissues, predicted worse prognosis, and was associated with strong metastatic potentials. IGFBP2 depletion significantly inhibited HCC cell proliferation, migration, and invasion, whereas IGFBP2 overexpression showed reverse phenotypes. The underlying mechanism involved IGFBP2-mediated nuclear localization of p65, which activated nuclear factor kappa B (NF-κB) and zinc finger E-Box binding homeobox 1 (ZEB1) transcription via binding to the gene promoter. CONCLUSION: This study for the first time identifies IGFBP2 as a novel therapeutic target in HCC that activates the NF-κB-ZEB1 signaling axis and promotes HCC tumorigenesis.