Inhibitory effects of angiotensin II receptor antagonists and leukotriene receptor antagonists on the transport of human organic anion transporter 4.

Human organic anion transporter 4 (OAT4) is the only member of the OAT family that is expressed in the placenta and also expressed in kidney. Although OAT4 has been shown to transport certain organic anions as well as other members of the OAT family, fewer numbers of substrates have been identified for OAT4 compared with OAT1 and OAT3, suggesting that the substrate specificity of OAT4 is greater than other OAT members. However, the substrate specificity of OAT4 remains to be investigated in detail.

YB-1 is important for an early stage embryonic development: neural tube formation and cell proliferation.

The eukaryotic Y-box-binding protein-1 (YB-1) is involved in the transcriptional and translational control of many biological processes, including cell proliferation. In clinical studies, the cellular level of YB-1 closely correlates with tumor growth and prognosis. To understand the role of YB-1 in vivo, especially in the developmental process, we generated YB-1 knock-out mice, which are embryonic lethal and exhibit exencephaly associated with abnormal patterns of cell proliferation within the neuroepithelium.

Expression and cellular localization of dbpC/Contrin in germ cell tumor cell lines.

The transcriptional regulation of the germ cell-specific cold-shock domain protein dbpC/Contrin was investigated, and the promoter region between -272 and -253 relative to the transcription start site was shown to be critical for the manifestation of cell-type specific transcription. In vivo footprint analysis demonstrated that the E-box located between -272 and -253 is protected in the dbpC/Contrin-positive germ cell tumor cell lines NEC8 and TERA1, but not in the dbpC/Contrin-negative bladder cancer cell line T24 or ovarian cancer cell line A2780. The promoter activity of the dbpC/Contrin gene was transactivated by co-transfection with c-Myc and the N-Myc expression plasmid.

A class 1 hemoglobin gene from Alnus firma functions in symbiotic and nonsymbiotic tissues to detoxify nitric oxide.

Actinorhizal symbiosis is as important in biological nitrogen fixation as legume-rhizobium symbiosis in the global nitrogen cycle. To understand the function of hemoglobin (Hb) in actinorhizal symbiosis, we characterized a Hb of Alnus firma, AfHb1. A cDNA that encodes nonsymbiotic Hb (nonsym-Hb) was isolated from a cDNA library of A.

Transcriptional upregulation of the human MRP2 gene expression by serine/threonine protein kinase inhibitors.

Transcriptional regulation by cellular signalling pathways of multidrug resistance proteins that pump anticancer drugs out of cells is one of key issues in the development of the multidrug resistance phenotype. In our study, we have used the reporter gene approach as well as determination of mRNA levels in two cancer cell lines of human origin, MCF-7 and A549, to study the regulation of multidrug resistance proteins 2 and 3 (MRP2 AND MRP3) by serine/threonine protein kinases. Since a prototypic PKC inducer, PMA, caused a marked upregulation of transcription from both human MRP2 and MRP3 promoters, a role for PKC isoforms in positive control of expression of these proteins could be postulated.

In vitro reconstitution of the GTPase-associated centre of the archaebacterial ribosome: the functional features observed in a hybrid form with Escherichia coli 50S subunits.

We cloned the genes encoding the ribosomal proteins Ph (Pyrococcus horikoshii)-P0, Ph-L12 and Ph-L11, which constitute the GTPase-associated centre of the archaebacterium Pyrococcus horikoshii. These proteins are homologues of the eukaryotic P0, P1/P2 and eL12 proteins, and correspond to Escherichia coli L10, L7/L12 and L11 proteins respectively. The proteins and the truncation mutants of Ph-P0 were overexpressed in E.

Eukaryotic control on bacterial cell cycle and differentiation in the Rhizobium-legume symbiosis.

Symbiosis between legumes and Rhizobium bacteria leads to the formation of root nodules where bacteria in the infected plant cells are converted into nitrogen-fixing bacteroids. Nodules with a persistent meristem are indeterminate, whereas nodules without meristem are determinate. The symbiotic plant cells in both nodule types are polyploid because of several cycles of endoreduplication (genome replication without mitosis and cytokinesis) and grow consequently to extreme sizes.

Expression of Y-box-binding protein dbpC/contrin, a potentially new cancer/testis antigen.

Y-box-binding proteins are members of the human cold-shock domain protein superfamily, which includes dbpA, dbpB/YB-1, and dbpC/contrin. dbpC/contrin is a germ cell-specific Y-box-binding protein and is suggested to function as a nuclear transcription factor and RNA-binding protein in the cytoplasm. Whereas ubiquitous dbpB/YB-1 expression has been well studied in various types of human carcinomas as a prognostic or predictive marker, the dbpC/contrin expression in human tumour cells has not been reported.

Suppression of root nodule formation by artificial expression of the TrEnodDR1 (coat protein of White clover cryptic virus 1) gene in Lotus japonicus.

TrEnodDR1 (Trifolium repens early nodulin downregulation 1) encodes a coat protein of White clover cryptic virus 1. Its expression in white clover was down-regulated at the time when root nodules formed. We surmised that its artificial expression would interfere with root nodulation.

The up-regulation of Y-box binding proteins (DNA binding protein A and Y-box binding protein-1) as prognostic markers of hepatocellular carcinoma.

Purpose: The development of hepatocellular carcinoma is associated with the chronic inflammation of the liver caused by various factors such as hepatitis B or C virus infection. Previously, we reported DNA binding protein A (dbpA) as a candidate molecule that can accelerate inflammation-induced hepatocarcinogenesis. DbpA belongs to the Y-box binding protein family, and Y-box binding protein-1 (YB-1), the prototype member of this family, is reported to be a prognostic marker of malignant diseases other than hepatocellular carcinoma.

Transcription factors and drug resistance.

Intrinsic or acquired resistance to anticancer agents is a major obstacle to the success of chemotherapy. Anticancer agents are known to modulate signal transduction pathways and alter expression of genes that play an important role in drug resistance. Emerging evidence suggests that the complexity of genomic response against anticancer agents arise from elaborate gene expression by multiple transcription factors.

A mode of assembly of P0, P1, and P2 proteins at the GTPase-associated center in animal ribosome: in vitro analyses with P0 truncation mutants.

Ribosomal P0, P1, and P2 proteins, together with the conserved domain of 28 S rRNA, constitute a major part of the GTPase-associated center in eukaryotic ribosomes. We investigated the mode of assembly in vitro by using various truncation mutants of silkworm P0. When compared with wild type (WT)-P0, the C-terminal truncation mutants CDelta65 and CDelta81 showed markedly reduced binding ability to P1 and P2, which was offset by the addition of an rRNA fragment covering the P0.

Functional analysis of organic cation transporter 3 expressed in human placenta.

The aim of this study is to investigate the placental transport mechanism of cationic compounds by comparison of the uptake of an organic cation into human placental basal membrane vesicles (BLMVs) with that into organic cation transporter 3 (OCT3)-expressing cells. Reverse transcription-polymerase chain reaction analysis demonstrated that OCT3 is the only OCT isoform expressed in the human placenta. The function of OCT3 was investigated by measuring the uptake of 1-methyl-4-phenylpyridinium (MPP(+)) into human embryonic kidney (HEK)293 cells stably expressing OCT3 (HEK/OCT3 cells).

Differential regulation of the human MRP2 and MRP3 gene expression by glucocorticoids.

Multidrug resistance proteins, which catalyse the detoxification of xenobiotics and excretion of metabolites, are very often controlled at the transcriptional level by interaction of exogenous compounds or hormones with nuclear receptors. Since synthetic glucocorticoids have found extensive use as anti-inflammatory drugs, also in the inhaled form in the treatment of asthma, lung cancer is potentially highly prone to transcriptional induction of multidrug resistance proteins by these steroids. MRP3 and MRP2 are major active anionic conjugate transporters in human cells and play a significant role in clinical multidrug resistance in cancer.

Symbiotic rhizobium and nitric oxide induce gene expression of non-symbiotic hemoglobin in Lotus japonicus.

We characterized the expression profiles of LjHb1 and LjHb2, non-symbiotic hemoglobin (non-sym-Hb) genes of Lotus japonicus. Although LjHb1 and LjHb2 showed 77% homology in their cDNA sequences, LjHb2 is located in a unique position in the phylogenetic tree of plant Hbs. The 5'-upstream regions of both genes contain the motif AAAGGG at a position similar to that in promoters of other non-sym-Hb genes.

Cyclic AMP-dependent Cl- secretion induced by thromboxane A2 in isolated human colon.

Increased release of thromboxane A(2) (TXA(2)) has been shown to be involved in inflammatory bowel diseases. In the present study, we have investigated the effect of a stable TXA(2) analogue (STA(2)) on the electrical parameters in isolated human colonic mucosa. In the human mucosa set between Ussing chambers, STA(2) stimulated Cl- secretion in a concentration-dependent manner with an EC(50) of 0.

ATP-binding cassette superfamily transporter gene expression in human soft tissue sarcomas.

The phenomenon of multidrug resistance (MDR) in various malignant neoplasms has been reported as being caused by one or multiple expressions of ATP-binding cassette (ABC) superfamily protein, including P-glycoprotein/multidrug resistance (MDR) 1 and the MDR protein (MRP) family. However, their expression levels and distribution within soft tissue sarcomas remain controversial. In 86 cases of surgically resected soft tissue sarcoma, intrinsic mRNA levels of MDR1, MRP1, MRP2 and MRP3 were assessed using a quantitative reverse transcriptase-PCR (RT-PCR) method.

The role of nuclear Y-box binding protein 1 as a global marker in drug resistance.

Gene expression can be regulated by nuclear factors at the transcriptional level. Many such factors regulate MDR1 gene expression, but what are the sequence elements and transcription factors that control the basal and inducible expression of this gene? The general principles through which transcription factors participate in drug resistance are now beginning to be understood. Here, we review the factors involved in the transcriptional regulation of the MDR1 gene.

Effects of grapefruit juice and orange juice components on P-glycoprotein- and MRP2-mediated drug efflux.

We investigated the effects of grapefruit juice (GFJ) and orange juice (OJ) on drug transport by MDR1 P-glycoprotein (P-gp) and multidrug resistance protein 2 (MRP2), which are efflux transporters expressed in human small intestine. We examined the transcellular transport and uptake of [(3)H]vinblastine (VBL) and [(14)C]saquinavir in a human colon carcinoma cell line (Caco-2) and in porcine kidney epithelial cell lines transfected with human MDR1 cDNA and human MRP2 cDNA, LLC-GA5-COL150, and LLC-MRP2, respectively. In Caco-2 cells, the basal-to-apical transports of [(3)H]VBL and [(14)C]saquinavir were greater than those in the opposite direction.

Baculovirus-mediated expression and isolation of human ribosomal phosphoprotein P0 carrying a GST-tag in a functional state.

We constructed an overexpression system for human ribosomal phosphoprotein P0, together with P1 and P2, which is crucially important for translation. Genes for these proteins, fused with the glutathione S-transferase (GST)-tag at the N-terminus, were inserted into baculovirus and introduced to insect cells. The fusion proteins, but not the proteins without the tag, were efficiently expressed into cells as soluble forms.

Control of nodule number by the phytohormone abscisic Acid in the roots of two leguminous species.

The effects of the phytohormone abscisic acid (ABA) on plant growth and root nodule formation were analyzed in Trifolium repense (white clover) and Lotus japonicus, which form indeterminate and determinate nodules, respectively. In T. repense, although the number of nodules formed after inoculation with Rhizobium leguminosarum bv.

Interleukin-1beta represses MRP2 gene expression through inactivation of interferon regulatory factor 3 in HepG2 cells.

The human multidrug resistance protein 2 (MRP2/ABCC2), expressed on the bile canalicular membrane, mediates the multispecific efflux of several organic anions, including conjugates of glucuronate, sulfate, and glutathione. Expression of MRP2 can be altered in response to environmental stimuli such as cholestasis and jaundice. We previously reported that MRP2 mRNA expression levels are decreased in the nontumorous part of hepatitis C virus-infected human liver tissues, and that inflammatory cytokines inhibit MRP2 expression in human hepatic (HepG2) cells.

RMF inactivates ribosomes by covering the peptidyl transferase centre and entrance of peptide exit tunnel.

In gram-negative bacteria such as Escherichia coli, protein synthesis is suppressed by the formation of 100S ribosomes under stress conditions. The 100S ribosome, a dimer of 70S ribosomes, is formed by ribosome modulation factor (RMF) binding to the 70S ribosomes. During the stationary phase, most of the 70S ribosomes turn to 100S ribosomes, which have lost translational activity.