Project description:In the current report, we report that ThbZIP1 is a direct target gene of the ThABF1 transcription factor. There are three ABRE motifs in the promoter of ThbZIP1, Yeast one-hybrid (Y1H) assays showed that a ABF protein, ThABF1, specifically binds to the ABRE motifs. The interaction between ThABF1 and the promoter of ThbZIP1 was further confirmed by transient expression assays in tobacco leaves. Chromatin Immunoprecipitation (ChIP) results suggested that binding of ThABF1 to ABRE motifs in the promoter of ThbZIP1 occurs in vivo in Tamarix hispida to regulate the expression of ThbZIP1. Moreover, ThABF1 and ThbZIP1 share similar expression patterns in response to salt, drought, ABA, methyl viologen (MV) and cold stress. Microarray analyses results showed there were 1,662 and 1,609 genes that were significantly upregulated or downregulated, respectively, under ABA stress conditions. ThbZIP1 regulated the genes via binding to the C-, G- or A-box motifs in their promoter sequences. Based on these data, the results suggested a regulatory network model mediated by ThbZIP1, under abiotic stress conditions, ThABF1 regulates the expression of ThbZIP1, and the activated ThbZIP1 binds to bZIP recognition sequences or other motifs to regulate the expression of genes containing these motifs in their promoters.
Project description:In the current report, we report that ThbZIP1 is a direct target gene of the ThABF1 transcription factor. There are three ABRE motifs in the promoter of ThbZIP1, Yeast one-hybrid (Y1H) assays showed that a ABF protein, ThABF1, specifically binds to the ABRE motifs. The interaction between ThABF1 and the promoter of ThbZIP1 was further confirmed by transient expression assays in tobacco leaves. Chromatin Immunoprecipitation (ChIP) results suggested that binding of ThABF1 to ABRE motifs in the promoter of ThbZIP1 occurs in vivo in Tamarix hispida to regulate the expression of ThbZIP1. Moreover, ThABF1 and ThbZIP1 share similar expression patterns in response to salt, drought, ABA, methyl viologen (MV) and cold stress. Microarray analyses results showed there were 1,662 and 1,609 genes that were significantly upregulated or downregulated, respectively, under ABA stress conditions. ThbZIP1 regulated the genes via binding to the C-, G- or A-box motifs in their promoter sequences. Based on these data, the results suggested a regulatory network model mediated by ThbZIP1, under abiotic stress conditions, ThABF1 regulates the expression of ThbZIP1, and the activated ThbZIP1 binds to bZIP recognition sequences or other motifs to regulate the expression of genes containing these motifs in their promoters. Differentially expression genes of ThbZIP1-overexpression plants and wild type of Columbia Arabidopsis thaliana were measured under ABA stressed and normal condition for 3 hours, respectively. Two independent experiments were performed at each treatment using different plants for each experiment.
Project description:Sesquiterpene lactones (STL) are lipophilic compounds synthesized as secondary metabolites in species across the plant kingdom, most notably in the family Asteraceae. One STL, found in North African Ambrosia maritima (A. maritima), and Caribbean Ambrosia hispida (A. hispida), is the compound ambrosin. Ambrosin exhibits several desirable pharmacologic characteristics, including compliance with the Rule of Five (RO5) pharmacokinetic profile. We have extracted ambrosin from A. maritima and A. hispida and demonstrated its cytotoxicity in bladder cancer and breast cancer cell lines in low micromolar ranges. Ambrosin also inhibited cancer stem cells and secondary spheroid formation of multiple bladder cancer and breast cancer cell lines. RNA Bru-Seq of ambrosin treated bladder cancer and breast cancer cells revealed a mitochondrial apoptotic gene signature as well as activation of glutathione metabolism, indicating the generation of reactive oxygen species (ROS). RNA Bru-Sequencing and drug target mapping also revealed potential antagonistic activity of ambrosin against the EGFR tyrosine kinase and Rho/Rac GTPases. Further studies showed that ambrosin inhibited EGFR auto-phosphorylation at tyrosine 1068 (Y1068) as well as the inhibition of Cdc42 GTPase and RhoC GTPase activity. These findings indicate novel mechanisms of action and justify further considerations for ambrosin pharmaco-development as a potential chemotherapeutic agent for advanced bladder cancer and triple negative breast cancer.