• The Plant Pathology Journal
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• 제27권1호
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• pp.20-25
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• 2011

Gibberella zeae (anamorph: Fusarium graminearum), a homothallic (self-ferile) ascomycete with ubiquitous geographic distribution, causes serious diseases in several cereal crops. Ascospores (sexual spores) produced by this fungal pathogen have been suggested as the main source of primary inoculum in disease development. Here, we report the function of a gene designated GzRUM1, which is essential for ascospore formation in G. zeae. The deduced product of GzRUM1 showed significant similarities to the human retinoblastoma (tumor suppressor) binding protein 2 and a transcriptional repressor, Rum1 in the corn smut fungus (Ustilago maydis). The transcript of GzRUM1 was detected during the both vegetative and sexual stages, but was more highly accumulated during the latter stage. In addition, no GzRUM1 transcript was detected in a G. zeae strain lacking a mating-type gene (MAT1-2), a master regulator for sexual development in G. zeae. Targeted deletion of GzRUM1 caused no dramatic changes in several traits except ascospore formation. The ${\Delta}$GzRUM1 strain produced perithecia (sexual fruit bodies) but not asci nor ascospores within them. This specific defect leading to an arrest in ascospore development suggests that GzRUM1, as Rum1 in U. maydis, functions as a transcriptional regulator during sexual reproduction in G. zeae.

• Journal of Microbiology and Biotechnology
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• 제29권8호
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• pp.1273-1280
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• 2019

Edwardsiella piscicida is the causative agent of edwardsiellosis, which has caused enormous economic losses worldwide. In our previous research, an attenuated live vaccine known as WED and based on the virulent strain E. piscicida EIB202 can effectively protect turbots against edwardsiellosis via intraperitoneal injection, while vaccination by immersion exhibits a weaker effect. During the development of the immersion vaccine, we surprisingly found the counts of ${\Delta}pEIB202/EIB202$ colonized on zebrafish were 100 times lower than those of EIB202. However, pEIB202 carries 53 predicted ORFs and has several copies in E. piscicida EIB202, impeding the study of its function. Thus, the replication region is located at a 1,980 bp fragment (from 18,837 to 20,816 bp), containing a transcriptional repressor and a replication protein. Moreover, the minimal replication plasmid, named pRep-q77, has low copies in both E. coli and E. piscicida, but is more stable in E. piscicida than in E. coli. This work lays a foundation for further examination of the function of the virulence plasmid pEIB202.

• 한국발생생물학회지:발생과생식
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• 제27권1호
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• pp.39-46
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• 2023

Pumilio (Pum) is an RNA-binding protein and translational repressor important to diverse biological processes. In the Drosophila ovary, Pum is expressed in female germline stem cells (GSCs), wherein it acts as an intrinsic stem cell maintenance factor via repressing target mRNAs that are as yet mostly unknown. Pum recognizes the Pum binding sequence (PBS) in the mRNA 3'UTR through its C-terminus Puf domain. Translational repression is mediated through its N-terminal domain, but the molecular mechanism remains largely unknown. We previously showed that Bag-of-marbles, a critical differentiation-promoting factor of female GSCs, physically interacts with the N-terminus of Pum. We further showed that this interaction is critical to Bam inhibition of Pum repressive action in cultured cells, but the physiological relevance was not addressed. Here we design an in vivo GFP translational reporter bearing the PBS in its 3'UTR and show that GFP expression is reduced in cells wherein Pum is known to be active. Furthermore, we demonstrate in pum mutant ovary that this GFP repression requires Pum, and also that the sensor faithfully monitors Pum activity. Finally, we show that forced expression of Bam inhibits Pum-mediated repression, validating that Bam inhibits Pum activity in vivo.

• Journal of Applied Biological Chemistry
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• 제66권
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• pp.128-137
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• 2023

Transcriptome analysis revealed that the sinR gene encoding a transition-state regulator of Bacillus pumilus, genetically close to B. subtilis, was expressed at high levels during growth. The sinR gene is the second gene of the sinIR operon consisting of three promoters and two structural genes in B. subtilis. This study used the sinIR promoter of B. subtilis DB104 to construct a recombinant protein expression system. First, the expression ability depending on the number of sinIR promoter was investigated using enhanced green fluorescent protein (eGFP). The expression level of eGFP was slightly higher when using two promoters (Psin2) than using original promoters. The Psin2 promoter was further engineered by modifying the repressor binding site and -35 and -10 regions. Shine-Dalgarno (SD) sequence of the sinI gene was modified to the consensus sequence. Finally, combining the engineered Psin2 promoter with the modified SD sequence increased the expression level of eGFP by about 13.4-fold over the original promoter. Our results suggest that the optimized sinIR promoter could be used as a novel tool for recombinant protein expression in B. subtilis.

• Journal of Microbiology and Biotechnology
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• 제17권12호
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• pp.2046-2055
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• 2007

Wild-type V. vulnificus cannot grow using lactose as the sole carbon source or take up the sugar. However, prolonged culture of this species in media containing lactose as the sole carbon source leads to the generation of a spontaneous lactose-utilizing (LU) mutant. This mutant showed strong ${\beta}$-galactosidase activity, whereas the wild-type strain showed a barely detectable level of the activity. A mutant with a lesion in a gene homologous to the lacZ of E. coli in the bacterium no longer showed ${\beta}$-galactosidase activity or generated spontaneous LU mutants, suggesting that the lacZ homolog is responsible for the catabolism of lactose, but the expression of the gene and genes for transport of lactose is tightly regulated. Genetic analysis of spontaneous LU mutants showed that all the mutations occur in a lacI homolog, which is located downstream to the lacZ and putative ABC-type lac permease genes. Consistent with this, a genomic library clone containing the lad gene, when present in trans, made the spontaneous LU mutants no longer able to utilize lactose as the sole carbon source. Taken together with the observation that excessive amounts of exogenously supplemented possible catabolic products of lactose have negative effects on the growth and survivability of V. vulnificus, we suggest that V. vulnificus has evolved to carry a repressor that tightly regulates the expression of lacZ to keep the intracellular toxic catabolic intermediates at a sublethal level.

• International Journal of Industrial Entomology and Biomaterials
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• 제12권2호
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• pp.57-61
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• 2006

Suppressor of cytokine signaling (SOCS) is known to be as a negative feedback regulator in Janus kinase signal transducer and activator of transcription signaling. Highly conserved SOCS box domain was cloned from a Korean malaria vector, Anopheles sinensis. Sequence analysis indicates that it has identity to Anopheles gambiae (96%), Aedes aegypti (94%), Drosophila melanogaster (78%), Mus musculus (72%) and Homo sapiens (72%), respectively. Tissue specificity RT-PCR demonstrated that the expression level of AsSOCS transcript was high at abdomen, midgut, and ovary, whereas developmental expression patterns showed that the level of AsSOCS was high at egg, early pupae, and adult female. On the other hand, RT-PCR analysis after bacterial challenge showed that SOCS mRNA was strongly induced in larvae. In addition, it was also induced by various immune elicitors such as lipoteicoic acid, CpG-DNA, and laminarin. It seems that AsSOCS, repressor of JAK-STAT pathway, is highly conserved in mosquito, and may play an important role in mosquito innate immune response.

• Molecules and Cells
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• 제41권4호
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• pp.290-300
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• 2018

Using an in vitro model of intestinal organoids derived from intestinal crypts, we examined effects of indole-3-carbinol (I3C), a phytochemical that has anticancer and aryl hydrocarbon receptor (AhR)-activating abilities and thus is sold as a dietary supplement, on the development of intestinal organoids and investigated the underlying mechanisms. I3C inhibited the in vitro development of mouse intestinal organoids. Addition of ${\alpha}$-naphthoflavone, an AhR antagonist or AhR siRNA transfection, suppressed I3C function, suggesting that I3C-mediated interference with organoid development is AhR-dependent. I3C increased the expression of Muc2 and lysozyme, lineage-specific genes for goblet cells and Paneth cells, respectively, but inhibits the expression of IAP, a marker gene for enterocytes. In the intestines of mice treated with I3C, the number of goblet cells was reduced, but the number of Paneth cells and the depth and length of crypts and villi were not changed. I3C increased the level of active nonphosphorylated ${\beta}$-catenin, but suppressed the Notch signal. As a result, expression of Hes1, a Notch target gene and a transcriptional repressor that plays a key role in enterocyte differentiation, was reduced, whereas expression of Math1, involved in the differentiation of secretory lineages, was increased. These results provide direct evidence for the role of AhR in the regulation of the development of intestinal stem cells and indicate that such regulation is likely mediated by regulation of Wnt and Notch signals.

• Journal of Microbiology and Biotechnology
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• 제2권1호
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• pp.26-34
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• 1992

The effect of induction temperature on fermentation parameters has been investigated extensively using Escherichia coli M5248[pNKM21], a producer of recombinant human interleukin-2 (rhIL-2). In this recombinant microorganism, the gene expression of rhIL-2 is regulated by the cI857 repressor and $P_L$ promoter system. The recombinant fermentation parameters studied in this work include the cell growth, protein synthesis, cell viability, plasmid stability, $\beta$-lactamase activity, and rhIL-2 productivity. Interrelationships of such fermentation parameters have been analyzed through a quantitative assessment of the experimental data set obtained at eight different culture conditions. While the expression of rhIL-2 gene was repressed at culture temperatures below $34^\circ{C}$ with little effect on other fermentation parameters, under the conditions of rhIL-2 production $>(36~44^\circ{C})$ the cell growth, plasmid stability, and $\beta$-lactamase activity were, as induction temperature was increased, more profoundly reduced. Although the rhIL-2 content in the insoluble protein fraction was maximum at $40^\circ{C}$, total rhIL-2 production in the culture volume was found to be highest at the induction temperature of $36^\circ{C}$. This was in contrast to the previously known optimum induction temperature of the P$_{L}$ promoter system $>(40~42^\circ{C})$.Explanations for such a discrepancy have been proposed based on a product formation kinetics, and their implications have been discussed in detail.l.

• 대한의생명과학회지
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• 제10권2호
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• pp.85-92
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• 2004

Immortalization of primary corneal cells has influence on pharmacy, medical and biological fields. Especially, investigation of immortalization mechanism using viral oncoproteins is useful for medical treatments, and these cell lines will be useful materials for toxic test of medical supplies and cell biological experiments. Rabbit corneal fibroblasts in culture undergo a finite number of divisions before they reach a terminally non-proliferating state known as replicative senescence. Therefore, we attempted to induce immortalization of rabbit corneal fibroblasts with SV 40 large T antigen. As a result of experiment, expression of SV 40 large T antigen was confirmed, and expression of proteins related to cell cycle repressor was decreased in the transfection group compared with non-transfection group. According to the results of cell cycle phase distribution test, SV 40 large T antigen-transfected cells had obtained higher proliferation rate than primary cells. It was confirmed that during induction of immortalization, SV 40 large T antigen was not able to increase telomerase activity. In conclusion, we made a rabbit corneal fibroblast cell line with SV40 large T antigen. This cell line will be useful for further studies of mammalian fibroblast biology, particularly with regard to angiogenesis and malignant transformation. In addition, this cell line offers opportunity for testing potential therapeutics and can be used for toxicity tests of materials or cosmetics. In the future, our cell line can potentially be utilized in a wide range of biology related fields.

• BMB Reports
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• 제44권4호
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• pp.267-272
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• 2011

ZAS3 is a large zinc finger transcription repressor that binds the ${\kappa}B$-motif via two signature domains of ZASN and ZASC. A loss-of-function study showed that lack of ZAS3 protein induced accelerated cell proliferation and tumorigenesis. Conversely, gain-of-function studies showed that ZAS3 repressed $NF{\kappa}B$-activated transcription by competing with $NF{\kappa}B$ for the ${\kappa}B$-motif. Based on these observations, we hypothesize that ZAS3 promotes apoptosis by interrupting anti-apoptotic activity of $NF{\kappa}B$. Here, we present evidence that upon $TNF{\alpha}$ stimulation, ZAS3 inhibits $NF{\kappa}B$-mediated cell survival and promotes caspase-mediated apoptosis. The inhibitory effect of ZAS3 on $NF{\kappa}B$ activity is mediated by neither direct association with $NF{\kappa}B$ nor disrupting nuclear localization of $NF{\kappa}B$. Instead, ZAS3 repressed the expression of two key anti-apoptotic genes of $NF{\kappa}B$, TRAF1 and TRAF2, thereby sensitizing cells to $TNF{\alpha}$-induced cell death. Taken together, our data suggest that ZAS3 is a tumor suppressor gene and therefore serves as a novel therapeutic target for developing anti-cancer drugs.