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Genetically Engineered Oncolytic Salmonella typhimurium
Published in Ananda M. Chakrabarty, Arsénio M. Fialho, Microbial Infections and Cancer Therapy, 2019
Tetracycline and doxycycline, an analog of tetracycline, exhibit properties of ideal inducers, including the effective induction of gene expression at very low concentrations (nmol/l range); good bioavailability, in that they can penetrate both bacterial and animal cells; nontoxicity at therapeutic concentrations, with approval for human clinical use; and stability, allowing long-term therapeutic activity. Repressor-regulated tetracycline efflux systems contain two genes, tetA and tetR, separated by an intergenic region. This intergenic region contains two promoters, one that drives the expression of tetR, which encodes the TetR repressor to suppress gene transcription, and one that drives the expression of tetA, which encodes the TetA efflux pump. The intergenic region also contains two tetO operators that regulate gene expression. In the absence of tetracycline/doxycycline, TetR is bound to tetO, which prevents the expression of TetA and TetR. In the presence of tetracycline, TetR binds to tetracycline and undergoes a conformational change that results in the dissociation of TetR from the tetO operators and expression of TetA and TetR. Because of the divergent nature of tetR and tetA transcription, replacing tetA with a gene of interest and placing a second gene of interest downstream of the repressor gene (tetR) would enable bilateral dual gene expression in a tetracycline-inducible system. Expression of target genes carried by a dualexpression vector showed excellent correlation between the tetA and tetR promoters, with the former considered more powerful for gene transcription. Bacterial cancer therapy with a dualexpression vector carrying a therapeutic gene under the control of the tetA promoter and a reporter gene under the control of the tetR promoter would therefore enable noninvasive monitoring of bacterial distribution and anticancer gene expression in vivo [11]. This type of vector would therefore result in effective anticancer therapy and imaging simultaneously or expression of synergistic anticancer molecules, further enhancing its therapeutic efficacy.
Modulation of SETDB1 activity by APQ ameliorates heterochromatin condensation, motor function, and neuropathology in a Huntington’s disease mouse model
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2021
Yu Jin Hwang, Seung Jae Hyeon, Younghee Kim, Sungsu Lim, Min Young Lee, Jieun Kim, Ashwini M. Londhe, Lizaveta Gotina, Yunha Kim, Ae Nim Pae, Yong Seo Cho, Jihye Seong, Hyemyung Seo, Yun Kyung Kim, Hyunah Choo, Hoon Ryu, Sun-Joon Min
The T-RExTM System (Invitrogen, Carlsbad, CA)-based inducible SETDB1/ESET cell line was established as previously described21,28. This system utilised two vectors, the pcDNA6/TR vector, a regulatory plasmid that expresses the tetracycline repressor (TetR), and pcDNA5/TO that contains a CMV promoter driving the expression of the gene of interest under the control of Tet-operator sequences. Myc-ESET was subcloned into the pcDNA5/TO vector from pcDNA-Myc-ESET construct, in which full length of ESET is cloned to a CMV-driven vector (Clontech, Palo Alto, CA). pcDNA5/TO-Myc-ESET was linearised and transfected into Q7 striatal cell clone over expressing pcDNA6/TR. The SETDB1/ESET cell clones were selected by hygromycin. For the induction of SETDB1/ESET, 4 µg/ml of doxycycline (Doxy) was treated into culture medium.
Proteomic response in Streptococcus gordonii DL1 biofilm cells during attachment to salivary MUC5B
Published in Journal of Oral Microbiology, 2021
Carolina Robertsson, Gunnel Svensäter, Zoltan Blum, Magnus E Jakobsson, Claes Wickström
One uncharacterized protein, SGO_0091, was more abundant in biofilms grown on MUC5B compared to LDP. This helical, transmembrane protein was found to be a putative ATP-binding cassette (ABC) transporter [27] and is suggested by gene neighborhood and gene co-occurrence to be functionally associated with a transcriptional regulator of the tetracycline repressor (TetR) family (SGO_0090) in S. gordonii DL1 [27]. In total, 12 TetR family transcriptional regulators are annotated in S. gordonii DL1 [27]. The products of the tet genes that are controlled by these transcriptional regulators confer resistance to tetracycline, hence, the name, but are also involved in a number of other biological processes, such as biofilm formation, catabolic pathways, stress responses, multidrug resistance and pathogenicity in both Gram-positive and Gram-negative bacteria [59].
Upregulation of peroxide scavenging enzymes and multidrug efflux proteins highlight an active sodium hypochlorite response in Pseudomonas fluorescens biofilms
Published in Biofouling, 2019
Daniel Lipus, Amit Vikram, Djuna Gulliver, Kyle Bibby
In addition, a gene encoding the multidrug efflux regulator TetR (PFLU_RS14210), a gene encoding the membrane protein TerC (PFLU_ RS105), a hypothetical membrane protein gene (PFLU_RS02795), and a gene encoding a Pseudomonas membrane protein (PFLU_RS17150) were also up-regulated (Table 1). TetR is a protein involved in the regulation of efflux pumps, which play an important role in antibiotic resistance. This protein controls the efflux of extracellular substances, especially tetracycline (Matsuo, et al. 2004). TerC plays a role in the efflux of tellurium ions during tellurite resistance (Chasteen, et al. 2009, Anantharaman, et al. 2012). Tellurite exposure generates superoxides and increases ROS levels, creating oxidative stress (Chasteen, et al. 2009). The function of PFLU_RS02795 and PFLU_RS17150 remains unknown; however, up-regulation levels as high as 9.20-fold and 19.55-fold suggest these two genes encode membrane proteins that play important roles in the active response to sodium hypochlorite.