• Journal of Microbiology
• /
• v.43 no.spc1
• /
• pp.110-117
• /
• 2005

Salmonella enterica serovar Typhimurium causes human gastroenteritis and a systemic typhoid-like infection in mice. A critical virulence determinant of Salmonella is the ability to invade mammalian cells. The expression of genes required for invasion is tightly regulated by environmental conditions and a variety of regulatory genes. The hilA regulator encodes an OmpR/ToxR family transcriptional regulator that activates the expression of invasion genes in response to both environmental and genetic regulatory factors. Work from several laboratories has highlighted that regulation of hilA expression is a key point for controlling expression of the invasive phenotype. A number of positive regulators of hilA expression have been identified including csrAB, sirA/barA, pstS, hilC/sirC/sprA, fis, and hilD. HilD, an AraC/XylS type transcriptional regulator, is of particular importance as a mutation in hilD results in a 14-fold decrease in chromosomal hilA::Tn5lacZY-080 expression and a 53-fold decrease in invasion of HEp-2 cells. It is believed that HilD directly regulates hilA expression as it has been shown to bind to hilA promoter sequences. In addition, our research group, and others, have identified genes (hilE, hha, pag, and lon) that negatively affect hilA transcription. HilE appears to be an important Salmonella-specific regulator that plays a critical role in inactivating hilA expression. Recent work in our lab has been directed at understanding how environmental signals that affect hilA expression may be processed through a hilE pathway to modulate expression of hilA and the invasive phenotype. The current understanding of this complex regulatory system is reviewed.

• Animal Bioscience
• /
• v.35 no.4
• /
• pp.533-543
• /
• 2022

Objective: Caspase-mediated apoptosis plays a crucial role in the regulation of endometrial and placental function in females. Caspase activity is tightly controlled by members of the inhibitors of apoptosis proteins (IAPs) family. However, the expression and regulation of IAPs at the maternal-conceptus interface has not been studied in pigs. Therefore, we determined the expression of IAP family members baculovirus IAP repeat-containing 1 (BIRC1) to BIRC6 at the maternal-conceptus interface in pigs. Methods: We obtained endometrial tissues from pigs at various stages of the estrous cycle and pregnancy, conceptus tissues during early pregnancy, and chorioallantoic tissues during mid- to late pregnancy and analyzed the expression of IAPs. Furthermore, we determined the effects of the steroid hormones estradiol-17β (E2) and progesterone on the expression of IAPs in endometrial explant tissue cultures. Results: During the estrous cycle, BIRC2 and BIRC5 expression varied cyclically, and during pregnancy, endometrial BIRC1, BIRC2, BIRC3, BIRC4, and BIRC5 expression varied in a stage-specific manner. Conceptus and chorioallantoic tissues also expressed IAPs during pregnancy. The BIRC2 and BIR3 mRNAs were localized to luminal epithelial cells, and BIRC4 proteins to glandular epithelial cells in the endometrium. Exposure of endometrial tissues to E2 increased the expression of BIRC6, while progesterone increased the expression of BIRC1, BIRC4, and BIRC6 in a dose-dependent manner. Conclusion: These results indicated that IAPs were expressed in the endometrium during the estrous cycle and at the maternal-conceptus interface during pregnancy in a stage-specific manner. In addition, steroid hormones were found to be responsible for the expression of some IAPs in pigs. Together, the results suggested that IAPs may play important roles in endometrial and placental functions by regulating caspase action and apoptosis at the maternal-conceptus interface.

• Journal of Families and Better Life
• /
• v.24 no.5 s.83
• /
• pp.1-15
• /
• 2006

This study explored the relationship between children's emotional competence, aggression and peer relationships. Participants were 164 third and 134 fourth grade children from five elementary schools in Seoul and Chenan. Emotional competence, aggression and peer relationships were assessed by means of a questionnaire, interview and observation. Results indicated that emotional understanding of self and others, sex, age, emotional expression and passive regulation strategies were significant variables in predicting children's aggression. Emotional understanding was the most predictable variable in relation to peer relationships. Emotional understanding, emotional regulation and emotional expression made independent contributions to aggression and peer relationships. Mediation analyses revealed that the significant connections between children's emotional competence and negative peer relationships were mostly mediated by aggression.

• BMB Reports
• /
• v.31 no.3
• /
• pp.249-253
• /
• 1998

The developmental regulation of Caenorhabditis elegans DNA topoisomerase I expression was examined using synchronized Caenorhabditis elegans cultures. Variations of the relative mRNA and protein levels of the enzyme during their development were measured by Northern and Western analyses, respectively. The mRNA level was the highest at the embryonic stage, decreasing rapidly to the one tenth level at the L1 stage, and then increasing by a few fold at the L4 and young adult stages. The protein level was the highest at the L1 stage, with gradual decreasing at the following stages until it showed a slight increase at the young adult stage. Based on our results of the expressional regulation, the possible roles of DNA topoisomerase I in the development of C. elegans are discussed.

• Genomics & Informatics
• /
• v.13 no.2
• /
• pp.40-44
• /
• 2015

DNA microarray and next-generation sequencing provide data that can be used for the genetic analysis of multiple quantitative traits such as gene expression levels, transcription factor binding profiles, and epigenetic signatures. In particular, chromatin opening is tightly coupled with gene transcription. To understand how these two processes are genetically regulated and associated with each other, we examined the changes of chromatin accessibility and gene expression in response to genetic variation by means of quantitative trait loci mapping. Regulatory patterns commonly observed in yeast and human across different technical platforms and experimental designs suggest a higher genetic complexity of transcription regulation in contrast to a more robust genetic architecture of chromatin regulation.

• BMB Reports
• /
• v.56 no.9
• /
• pp.514-519
• /
• 2023

Methyltransferase-like 3 (METTL3), a key component of the m⁶A methyltransferase complex, regulates the splicing, nuclear transport, stability, and translation of its target genes. However, the mechanism underlying the regulation of METTL3 expression by alternative splicing (AS) remains unknown. We analyzed the expression pattern of METTL3 after AS in human tissues and confirmed the expression of an isoform retaining introns 8 and 9 (METTL3-IR). We confirmed the different intracellular localizations of METTL3-IR and METTL3 proteins using immunofluorescence microscopy. Furthermore, the endogenous expression of METTL3-IR at the protein level was different from that at the mRNA level. We found that 3'-UTR generation by intron retention (IR) inhibited the export of METTL3-IR mRNA to the cytoplasm, which in turn suppressed protein expression. To the best of our knowledge, this is the first study to confirm the regulation of METTL3 gene expression by AS, providing evidence that the suppression of METTL3 protein expression by IR is an integral part of the mechanism by which 3'-UTR generation regulates protein expression via inhibition of RNA export to the cytoplasm.

• Molecules and Cells
• /
• v.28 no.3
• /
• pp.201-207
• /
• 2009

Silibinin is a polyphenolic flavonoid compound isolated from milk thistle (Silybum marianum), with known hepatoprotective, anticarcinogenic, and antioxidant effects. Herein, we show that silibinin inhibits receptor activator of $NF-{\kappa}B$ ligand (RANKL)-induced osteoclastogenesis from RAW264.7 cells as well as from bone marrow-derived monocyte/macrophage cells in a dose-dependent manner. Silibinin has no effect on the expression of RANKL or the soluble RANKL decoy receptor osteoprotegerin (OPG) in osteoblasts. However, we demonstrate that silibinin can block the activation of $NF-{\kappa}B$, c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein (MAP) kinase, and extracellular signal-regulated kinase (ERK) in osteoclast precursors in response to RANKL. Furthermore, silibinin attenuates the induction of nuclear factor of activated T cells (NFAT) c1 and osteoclast-associated receptor (OSCAR) expression during RANKL-induced osteoclastogenesis. We demonstrate that silibinin can inhibit $TNF-{\alpha}$-induced osteoclastogenesis as well as the expression of NFATc1 and OSCAR. Taken together, our results indicate that silibinin has the potential to inhibit osteoclast formation by attenuating the downstream signaling cascades associated with RANKL and $TNF-{\alpha}$.

• Natural Product Sciences
• /
• v.10 no.5
• /
• pp.197-206
• /
• 2004

Cytochrome P4501A2 (CYP1A2) is responsible for the metabolic activation of a number of aromatic amines and amides to mutagenic and carcinogenic moieties. Considerable variations in the level of CYP1A2 expression in humans have been reported. Thus, the level of human CYP1A2 may determine an individuals susceptibility to these chemicals. Given its importance, the molecular mechanisms of CYP1A2 regulation have been studied by many groups. Direct interactions between transcription factors with the promoters of the gene represent one of the primary means by which the expression of CYP1A2 is controlled. In this review, several important cis elements, transcription factors and the effects of deacetylation/methylation of promoter regions that play an important role in the induction by PAHs as well as constitutive expression of human CYP1A2 are discussed.

• Molecular & Cellular Toxicology
• /
• v.2 no.4
• /
• pp.223-228
• /
• 2006

Several plant-derived cannabinoids and endogenous ligands for cannabinoid receptors such as 2-arachidonyl-glycerol have been known to inhibit interleukin-2 (IL-2) expression. In the present study, we utilized arachidonylethanolamide (AEA), a putative endogenous ligand for cannabinoid receptors, to determine whether AEA modulated the expression of IL-2. AEA inhibited phorbol 12-myristate 13-acetate (PMA) plus ionomycin (Io)-induced IL-2 protein secretion and mRNA expression in EL-4 mouse T-cells as determined by ELISA and RT-PCR, respectively. To further characterize the inhibitory mechanism of AEA at the transcriptional level, we performed promoter study for IL-2 gene in PMA/Io-stimulated EL-4 cells. AEA decreased the transcriptional activity of the nuclear factor of activated T-cells (NF-AT) as well as the IL-2 promoter activity. These results suggest that AEA suppresses IL-2 expression and that the inhibition is mediated, at least in part, through the down-regulation of NF-AT.

• The Korean Journal of Physiology and Pharmacology
• /
• v.3 no.3
• /
• pp.315-320
• /
• 1999

Molecular regulation of the renin-angiotensin system (RAS) was investigated in deoxycorticosterone acetate (DOCA)-salt hypertension. The expression of renin, angiotensinogen and angiotensin II receptor genes in the kidney and liver was determined by Northern blot analysis in rats which were made DOCA-salt hypertensive over the period of 2 or 4 weeks. Along with the hypertension, renin mRNA was decreased in the remnant kidney. The expression of angiotensinogen gene was not significantly altered in the kidney, but was significantly decreased in the liver. The expression of angiotensin II receptor gene was increased in the kidney, while it remained unaltered in the liver. The duration of hypertension did not affect the altered gene expression. It is suggested that the components of RAS are transcriptionally regulated in DOCA-salt hypertension in a tissue-specific manner.