• BMB Reports
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• v.47 no.9
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• pp.518-523
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• 2014

The maternal transcription factor Dorsal (Dl) functions as both an activator and a repressor in a context-dependent manner to control dorsal-ventral patterning in the Drosophila embryo. Previous studies have suggested that Dl is an intrinsic activator and its repressive activity requires additional corepressors that bind corepressor-binding sites near Dl-binding sites. However, the molecular identities of the corepressors have yet to be identified. Here, we present evidence that Capicua (Cic) is involved in Dl-mediated repression in the zerkn$\ddot{u}$llt (zen) ventral repression element (VRE). Computational and genetic analyses indicate that a DNA-binding consensus sequence of Cic is highly analogous with previously identified corepressor-binding sequences and that Dl failed to repress zen expression in lateral regions of cic mutant embryos. Furthermore, electrophoretic mobility shift assay (EMSA) shows that Cic directly interacts with several corepressor-binding sites in the zen VRE. These results suggest that Cic may function as a corepressor by binding the VRE.

• Biomedical Science Letters
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• v.12 no.4
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• pp.385-391
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• 2006

Heterotrimeric GTP binding proteins (G proteins) mediate signals generated by neurotransmitters and hormones Among G proteins, Go is found in a large quantity in brain and growth cone membranes of neurons. In spite of its abundance in neurons, the role of Go is not fully understood. In our previous study, we identified promyelocytic leukemia zinc finger protein (PLZF) as an interacting partner of alpha subunit of Go ($Go{\alpha}$) and confirmed their interaction employing several biochemical assays. To date, it is reported that PLZF functioned as a cell growth suppressor and a transcription repressor. To determine effect of $Go{\alpha}$ and PLZF interaction on the cellular function of PLZF, we performed luciferase reporter gene assay and BrdU incorporation assay. Co-expression of $Go{\alpha}$ and PLZF synergistically increased the effect of PLZF alone. These results suggest that $Go{\alpha}$ may act as cellular activator of PLZF. This novel feature of Go may provide insights into understanding diverse role of Go-coupled receptor as well as its cellular actions.

• Biomolecules & Therapeutics
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• v.17 no.1
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• pp.12-16
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• 2009

One of the WHSC1/MMSET/NSD2 variant RE-IIBP is a histone H3-K27 methyltransferase with transcriptional repression activity. Overexpression of RE-IIBP in various types of leukemia suggests it's role in leukemogenesis. Here we identify two proteins, KRAB zinc finger protein ZNF 350 and enolase-1 as RE-IIBP interacting proteins by yeast two-hybrid screening and confirmed direct interaction in vivo and in vitro. Both proteins have been known for their role in transcriptional repression. Reporter assays using transient transfection demonstrated that both ZNF 350 and enolase-1 proteins synergistically repressed transcription with RE-IIBP, respectively. These results indicate both proteins have roles in RE-IIBP mediated transcriptional repression by involving co-repressor complex.

• Journal of Microbiology and Biotechnology
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• v.22 no.8
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• pp.1133-1140
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• 2012

Ribonucleic acid interference (RNAi) inhibits the expression of target genes in a sequence-specific manner, and shows potential for gene knockdown in filamentous fungi, in which the locus-specific gene knockout occurs in low frequency. In this study, the function of the repressor of cellulase expression I (ACEI) was verified in Trichoderma koningii (T. koningii) YC01 through RNAi, and ace1-silenced strains with improved cellulase productivity were obtained. An expression cassette that transcribed the interfering double-stranded RNA (dsRNA) of ace1 was constructed and transformed into T. koningii, and the transformants, in which the expression of ace1 was successfully silenced, were selected. As a result of the ace1 gene silencing, the expression levels of the main cellulase and xylanase genes were elevated, and the enhanced production of total proteins, cellulase, and xylanase was observed in the cultivation. In addition, the down-regulation of ace1 resulted in an increasing expression of xyr1, but no clear variation in the expression of cre1, which suggested that ACEI acted as a repressor of the xyr1 transcription, but was not involved in the regulation of the cre1 expression. The results of this work indicate that ace1 is a valid target gene for enhancing enzyme production in T. koningii, and RNAi is an appropriate tool for improving the properties of industrial fungi.

• International Journal of Oral Biology
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• v.35 no.2
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• pp.69-74
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• 2010

The mu opioid receptor (MOR) has been regarded as the main site of interaction with analgesics in major clinical use, particularly morphine. The repressor element-1 silencing transcription factor (REST) functions as a transcriptional repressor of neuronal genes in non-neuronal cells. However, it is expressed in certain mature neurons, suggesting that it may have complex and novel roles. In addition, the interactions between MOR and REST and their functions remain unclear. In this study, we examined the effects of morphine on the expression of REST mRNA and protein in human neuroblastoma NMB cells to investigate the roles of REST induced by MOR activation in neuronal cells. To determine the effects of morphine on REST expression, we performed RT-PCR, real-time quantitative RT-PCR, western blot analysis and radioligand binding assays in NMB cells. By RTPCR and real-time quantitative RT-PCR, the expression of REST was found to be unchanged by either the MOR agonist morphine or the MOR specific antagonist CTOP. By western blot, morphine was shown to significantly inhibit the expression of REST, but this suppression was completely blocked by treatment with CTOP. In the radioligand binding assay, the overexpression of REST led to an increased opioid ligand binding activity of endogenous MOR in the NMB cells. These results together suggest that morphine inhibits the expression of REST in human neuroblastoma cells through a post-transcriptional regulatory mechanism mediated through MOR.

• Journal of Life Science
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• v.14 no.5
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• pp.732-740
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• 2004

MCM proteins are essential for eukaryotic DNA replication, playing roles in the initiation and elongation of DNA replication. MCM proteins expression is much higher in malignant tissues than normal tissues. Several reports have indicated the usefulness of MCM proteins as markers of cancer cells in histopathological diagnosis. However, the cause of enhanced expression of MCM proteins in cancer cells remain to be clarified. The purpose of this study is to examine the relative transcriptional activities of human mcm gene promoters in cancer and normal cells. The minimal promoter region required for transcription of a luciferase reporter gene was contained an E-box and one E2F site. In addition, luciferase activities from mcm7 and mcm2 promoter/luciferase gene reporter constructs were significantly increased in cancer cells at 8 times compared with normal cells. E-box and E2F binding site in the promoter of mcm genes are responsible for different mechanism of transcription regulation on the cellular environment.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.12
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• pp.1679-1683
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• 2017

Objective: An experiment was conducted to study the association between the single nucleotide polymorphisms (SNPs) in 5'-untranslated regions (5'-UTR) of equine chorionic gonadotropin (eCG) genes and the serum eCG levels. Methods: SNPs in 5'-UTR of eCG genes were screened across 10 horse breeds, including 7 Chinese indigenous breeds and 3 imported breeds using iPLEX chemistry, and the association between the serum eCG levels of 174 pregnant Da'an mares and their serum eCG levels (determined with ELISA) was analyzed. Results: Four SNPs were identified in the 5'-UTR of the $eCG{\alpha}$ gene, and one of them was unique in the indigenous breeds. There were 2 SNPs detected at the 5' end of the $eCG{\beta}$ subunit gene, and one of them was only found in the Chinese breeds. The SNP g.39948246T>C at the 5'-UTR of $eCG{\alpha}$ was associated significantly with eCG levels of 75-day pregnant mare serum (p<0.05) in Da'an mares. Prediction analysis on binding sites of transcription factors showed that the g.39948246T>C mutation causes appearance of the specific binding site of hepatocyte nuclear factor 3 forkhead homolog 2 (HFH-2), which is a transcriptional repressor belonging to the forkhead protein family of transcription factors. Conclusion: The SNP g.39948246T>C at the 5'-UTR of $eCG{\alpha}$ is associated with eCG levels of 75-day pregnant mare serum (p<0.05).

• Molecules and Cells
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• v.42 no.2
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• pp.123-134
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• 2019

Lysophosphatidic acid (LPA) is an endogenous lysophospholipid with signaling properties outside of the cell and it signals through specific G protein-coupled receptors, known as $LPA_{1-6}$. For one of its receptors, $LPA_1$ (gene name Lpar1), details on the cis-acting elements for transcriptional control have not been defined. Using 5'RACE analysis, we report the identification of an alternative transcription start site of mouse Lpar1 and characterize approximately 3,500 bp of non-coding flanking sequence 5' of mouse Lpar1 gene for promoter activity. Transient transfection of cells derived from mouse neocortical neuroblasts with constructs from the 5' regions of mouse Lpar1 gene revealed the region between -248 to +225 serving as the basal promoter for Lpar1. This region also lacks a TATA box. For the region between -761 to -248, a negative regulatory element affected the basal expression of Lpar1. This region has three E-box sequences and mutagenesis of these E-boxes, followed by transient expression, demonstrated that two of the E-boxes act as negative modulators of Lpar1. One of these E-box sequences bound the HeLa E-box binding protein (HEB), and modulation of HEB levels in the transfected cells regulated the transcription of the reporter gene. Based on our data, we propose that HEB may be required for a proper regulation of Lpar1 expression in the embryonic neocortical neuroblast cells and to affect its function in both normal brain development and disease settings.

• Molecules and Cells
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• v.26 no.5
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• pp.443-453
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• 2008

The Bric-a-brac, Tramtrack, Broad-complex (BTB) domain is a protein-protein interaction domain that is found in many zinc finger transcription factors. BTB containing proteins play important roles in a variety of cellular functions including regulation of transcription, regulation of the cytoskeleton, protein ubiquitination, angiogenesis, and apoptosis. Here, we report the cloning and characterization of a novel human gene, KLHL31, from a human embryonic heart cDNA library. The cDNA of KLHL31 is 5743 bp long, encoding a protein product of 634 amino acids containing a BTB domain. The protein is highly conserved across different species. Western blot analysis indicates that the KLHL31 protein is abundantly expressed in both embryonic skeletal and heart tissue. In COS-7 cells, KLHL31 proteins are localized to both the nucleus and the cytoplasm. In primary cultures of nascent mouse cardiomyocytes, the majority of endogenous KLHL31 proteins are localized to the cytoplasm. KLHL31 acts as a transcription repressor when fused to GAL4 DNA-binding domain and deletion analysis indicates that the BTB domain is the main region responsible for this repression. Overexpression of KLHL31 in COS-7 cells inhibits the transcriptional activities of both the TPA-response element (TRE) and serum response element (SRE). KLHL31 also significantly reduces JNK activation leading to decreased phosphorylation and protein levels of the JNK target c-Jun in both COS-7 and Hela cells. These results suggest that KLHL31 protein may act as a new transcriptional repressor in MAPK/JNK signaling pathway to regulate cellular functions.

• BMB Reports
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• v.40 no.4
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• pp.517-524
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• 2007

There were many different families of zinc finger proteins that contained multiple cysteine and/or histidine residues and used zinc to stabilize their folds. The classical C2H2 zinc finger proteins were the founding members of this superfamily and were among the most abundant proteins in eukaryotic genomes. C2H2 proteins typically contained several C2H2 fingers that made tandem contacts along the DNA. Here we reported a novel C2H2 type zinc finger gene, ZNF438, which encoded 828 amino acids that formed five zinc finger domains. Bioinformatics analysis revealed that the ZNF438 was mapped to human chromosome 10p11.2 and shared 62% identity with rat and mouse homologues. RT-PCR analysis indicated that it was ubiquitously expressed in 18 human adult tissues. With immunofluorescence assay, it was shown that the exogenous Flag-tagged ZNF438 was located in nucleus of COS-7 cells. To further explore the function of ZNF438, we examined the transcriptional activity of ZNF438 protein by transfecting recombinant pM-ZNF438 into mammalian cells. The subsequent analysis based on the duel luciferase assay system showed that ZNF438 was a transcriptional repressor.