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R Yano

Publications and source records attributed to R Yano.

At least 55 records · Page 3Linked to original sources
PubMed1998

Expression of receptors for neuregulins, ErbB2, ErbB3 and ErbB4, in developing mouse cerebellum.

We have examined the expression of ErbB2, ErbB3 and ErbB4 in developing mouse cerebellum. ErbB2, ErbB3 and ErbB4 were all expressed in granule cells during cerebellar development. However, the expression pattern for each ErbB receptor changed with the developmental stage. Variations of signal transduction pathway through combinations of these ErbB receptors might have important roles in controlling cerebellar postnatal development.

Animals↗
PubMed1998

The importance of glucose transport activity as the rate-limiting step of 2-deoxyglucose uptake in tumor cells in vitro.

Glucose transporter (GLUT) expression and hexokinase activity are thought to be related to high [18F]-fluorodeoxyglucose (FDG) uptake in tumor cells, but their relative importance is still unknown. To determine which is the predominant factor in FDG uptake in tumor cells, cultured tumor cell lines and a normal cell line were studied in vitro with respect to 2-deoxyglucose (DG) uptake, hexokinase activity, and the initial uptake rate of 3-O-methylglucose (3-O-MG) transport, which is generally accepted as indicating the amount of GLUT expressed on the plasma membrane. In 16 types of tumor cells and one fibroblast cell line, DG uptake was assessed for 60 min, the initial uptake rate of 3-O-MG transport was measured for 1 min, and total hexokinase activity, including that in the mitochondrial fraction, was determined. Across all 16 tumor cell lines, there was a significant correlation between DG uptake and 3-O-MG transport (p = 0.0012, F test), but not between DG uptake and hexokinase activity. Hexokinase activity of the tumor cells was comparable to that of the human fibroblast cells in the exponential growth phase. Most tumor cells showed higher DG uptake and 3-O-MG transport than the human fibroblast cells. The results suggest that DG uptake of cultured tumor cells is governed by GLUT expression, which may be a distinct characteristic of the neoplastic process.

3-O-Methylglucose↗
PubMed1998

[Estimation of adverse drug reactions by the evaluation scores of subjective symptoms (complaints) and background of patients. I. Drug-induced liver disorders].

The purpose of this study was to develop, implement, and assess an estimation procedure for preventing drug-induced liver disorders. We have built a database for CARPIS (case reports of adverse drug reaction and poisoning information services) since 1987, and the case reports of adverse drug reaction accumulated in the CARPIS database to be total about 11,000. We studied the estimation procedure by evaluating the subjective symptoms, backgrounds and laboratory data of patients in 199 cases cumulated in the CARPIS database. The evaluation scores were created on the basis of the subjective symptoms and backgrounds of the patients. Then, we re-estimated 199 cases with the evaluation scores, among which were 165 cases (82.9%) in 199 cases drug-induced liver disorders. For the rest of 34 cases (17.1%) drug-induced liver disorders could not be estimated from our evaluation scores. These 34 cases were either those which the subjective symptoms were not described in their reports, because the patients were hospitalized for other diseases and drug-induced liver disorders were discovered by a clinical examination, or cases of infants for whom it was difficult to confirm the subjective symptoms. The validity of this evaluation scores were sensitivity = 82.9%, specificity = 91.0% and predictive value of positive test = 94.8%. To apply this evaluation scores onto the clinical practice, we prepared an evaluation form for the subjective symptoms and backgrounds of the patients with drug suspecting-induced liver disorders.

Adverse Drug Reaction Reporting Systems↗
PubMed1997

Functional coupling of the nociceptin/orphanin FQ receptor with the G-protein-activated K+ (GIRK) channel.

Nociceptin/orphanin FQ is a heptadecapeptide which was recently isolated from brains. It induces hyperalgesia, in contrast to the analgesic effects of opioid ligands, although it and its receptor structurally resemble opioid peptides and opioid receptors, respectively. To investigate the molecular mechanism underlying nociceptin/orphanin FQ actions, we performed Xenopus oocyte expression assays, in situ hybridization histochemistry and electrophysiological analyses of neurons. We found that the nociceptin/orphanin FQ receptor is functionally coupled with the G-protein-activated K+ (GIRK) channel in Xenopus oocytes, and that the receptor mRNA and GIRK1 mRNA co-exist in various neurons, including hippocampal pyramidal cells. Furthermore, we found that nociceptin/orphanin FQ induces hyperpolarizing currents via inward-rectifier K+ channels in hippocampal pyramidal cells, suggesting that the nociceptin/orphanin FQ receptor couples with the GIRK channel in this region. We conclude that the nociceptin/orphanin FQ receptor couples with the GIRK channel in various neurons, including hippocampal pyramidal cells, thereby modulating neuronal excitability.

Animals↗
PubMed1994

Yeast Srp1p has homology to armadillo/plakoglobin/beta-catenin and participates in apparently multiple nuclear functions including the maintenance of the nucleolar structure.

SRP1, a suppressor of certain temperature-sensitive mutations in RNA polymerase I in Saccharomyces cerevisiae, encodes a protein that is associated with nuclear pores. By using a system of conditional SRP1 expression and by isolating temperature-sensitive srp1 mutants, we have demonstrated that Srp1p is essential for maintenance of the crescent-shaped nucleolar structure, RNA transcription, and the proper functions of microtubules as inferred from analysis of nuclear division/segregation and immunofluorescence microscopy of microtubules. Different mutant alleles showed significantly different phenotypes in relation to these apparently multiple functional roles of the protein. We have also found that eight imperfect 42-amino-acid tandem repeats present in Srp1p are similar to the 42-amino-acid repeats in armadillo/plakoglobin/beta-catenin proteins present in adhesive junction complexes of higher eukaryotes. We discuss this similarity in connection with the observed pleiotropic effects of srp1 mutations.

Amino Acid Sequence↗
PubMed1993

Gene RRN4 in Saccharomyces cerevisiae encodes the A12.2 subunit of RNA polymerase I and is essential only at high temperatures.

We have previously isolated mutants of Saccharomyces cerevisiae that are primarily defective in transcription of 35S rRNA genes by RNA polymerase I and have identified genes (RRN1 to RRN9) involved in this process. We have now cloned the RRN4 gene by complementation of the temperature-sensitive phenotype of the rrn4-1 mutant and have determined its complete nucleotide sequence. The following results demonstrate that the RRN4 gene encodes the A12.2 subunit of RNA polymerase I. First, RRN4 protein expressed in Escherichia coli reacted with a specific antiserum against A12.2. Second, amino acid sequences of three tryptic peptides obtained from A12.2 were determined, and these sequences are found in the deduced amino acid sequence of the RRN4 protein. The amino acid sequence of the RRN4 protein (A12.2) is similar to that of the RPB9 (B12.6) subunit of yeast RNA polymerase II; the similarity includes the presence of two putative zinc-binding domains. Thus, A12.2 is a homolog of B12.6. We propose to rename the RRN4 gene RPA12. Deletion of RPA12 produces cells that are heat but not cold sensitive for growth. We have found that in such null mutants growing at permissive temperatures, the cellular concentration of A190, the largest subunit of RNA polymerase I, is lower than in the wild type. In addition, the temperature-sensitive phenotype of the rpa12 null mutants can be partially suppressed by RPA190 (the gene for A190) on multicopy plasmids. These results suggest that A12.2 plays a role in the assembly of A190 into a stable polymerase I structure.

Amino Acid Sequence↗
PubMed1992

Cloning and characterization of SRP1, a suppressor of temperature-sensitive RNA polymerase I mutations, in Saccharomyces cerevisiae.

The SRP1-1 mutation is an allele-specific dominant suppressor of temperature-sensitive mutations in the zinc-binding domain of the A190 subunit of Saccharomyces cerevisiae RNA polymerase I (Pol I). We found that it also suppresses temperature-sensitive mutations in the zinc-binding domain of the Pol I A135 subunit. This domain had been suggested to be in physical proximity to the A190 zinc-binding domain. We have cloned the SRP1 gene and determined its nucleotide sequence. The gene encodes a protein of 542 amino acids consisting of three domains: the central domain, which is composed of eight (degenerate) 42-amino-acid contiguous tandem repeats, and the surrounding N-terminal and C-terminal domains, both of which contain clusters of acidic and basic amino acids and are very hydrophilic. The mutational alteration (P219Q) responsible for the suppression was found to be in the central domain. Using antibody against the SRP1 protein, we have found that SRP1 is mainly localized at the periphery of the nucleus, apparently more concentrated in certain regions, as suggested by a punctate pattern in immunofluorescence microscopy. We suggest that SRP1 is a component of a larger macromolecular complex associated with the nuclear envelope and interacts with Pol I either directly or indirectly through other components in the structure containing SRP1.

Amino Acid Sequence↗
PubMed1991

Synthesis of large rRNAs by RNA polymerase II in mutants of Saccharomyces cerevisiae defective in RNA polymerase I.

The 35S rRNA gene of the yeast Saccharomyces cerevisiae was fused to the GAL7 promoter. This hybrid gene, when present on a multicopy plasmid and induced by galactose, suppressed the growth defects of a temperature-sensitive RNA polymerase I (pol I) mutant and those of a mutant in which the gene for the second largest subunit of pol I was deleted. Analysis of pulse-labeled RNA directly demonstrated that rRNA synthesis in this deletion mutant is from the GAL7 promoter. These experiments show that the sole essential function of pol I is the transcription of the rRNA genes, that pol I is not absolutely required for the synthesis of rRNA and ribosomes or cell growth if 35S rRNA synthesis is achieved by some other means, and that the tandemly repeated structure of the chromosomal rRNA genes is also not absolutely required for the synthesis of rRNA and ribosomes.

Base Sequence↗
PubMed1991

Suppressor analysis of temperature-sensitive mutations of the largest subunit of RNA polymerase I in Saccharomyces cerevisiae: a suppressor gene encodes the second-largest subunit of RNA polymerase I.

The SRP3-1 mutation is an allele-specific suppressor of temperature-sensitive mutations in the largest subunit (A190) of RNA polymerase I from Saccharomyces cerevisiae. Two mutations known to be suppressed by SRP3-1 are in the putative zinc-binding domain of A190. We have cloned the SRP3 gene by using its suppressor activity and determined its complete nucleotide sequence. We conclude from the following evidence that the SRP3 gene encodes the second-largest subunit (A135) of RNA polymerase I. First, the deduced amino acid sequence of the gene product contains several regions with high homology to the corresponding regions of the second-largest subunits of RNA polymerases of various origins, including those of RNA polymerase II and III from S. cerevisiae. Second, the deduced amino acid sequence contains known amino acid sequences of two tryptic peptides from the A135 subunit of RNA polymerase I purified from S. cerevisiae. Finally, a strain was constructed in which transcription of the SRP3 gene was controlled by the inducible GAL7 promoter. When this strain, which can grow on galactose but not on glucose, was shifted from galactose medium to glucose medium, a large decrease in the cellular concentration of A135 was observed by Western blot analysis. We have also identified the specific amino acid alteration responsible for suppression by SRP3-1 and found that it is located within the putative zinc-binding domain conserved among the second-largest subunits of eucaryotic RNA polymerases. From these results, it is suggested that this putative zinc-binding domain is in physical proximity to and interacts with the putative zinc-binding domain of the A190 subunit.

Alleles↗
PubMed1990

A mutation that enhances synthesis of sigma 32 and suppresses temperature-sensitive growth of the rpoH15 mutant of Escherichia coli.

The rpoH15 mutant cannot grow at or above 34 degrees C, because it produces an altered sigma 32 protein that is largely deficient in the transcription of the heat shock genes. Extragenic suppressor mutations (suhB) located at 55 min on the Escherichia coli chromosome endowed the mutant cell with the ability to grow at 40 degrees C and the inability to grow at 25 degrees C. One such mutation (suhB2), studied in detail, markedly enhanced the rate of sigma 32 synthesis and the rpoH mRNA level during steady-state growth at 37 to 40 degrees C but little affected the cellular content of sigma 32 or the induction of heat shock proteins. In the isogenic rpoH+ strain, neither sigma 32 synthesis nor the rpoH mRNA level was enhanced by the suhB suppressor. Furthermore, expression of the rpoH-lacZ gene fusion, but not the operon fusion, was much higher in the suhB mutant than in the wild type or the suhB rpoH+ strain, indicating that suhB affects rpoH expression primarily at the level of translation. suhB probably acts to increase sigma 32 synthesis by affecting the regulatory circuit of rpoH expression or by modulating certain parameters in protein synthesis. Consistent with these findings, overproduction of the mutant (rpoH15) sigma 32 by multicopy plasmid enabled the rpoH15 or delta rpoH (deletion) mutant to grow at up to 40 degrees C. Plasmids containing an E. coli DNA segment of 1.0 kilobase could complement the cold-sensitive phenotype of the suhB2 mutant. Nucleotide sequence analysis revealed that the segment contained an open reading frame encoding a protein of 29,128 daltons.

Amino Acid Sequence↗
PubMed1990

Transcriptional regulation of the heat shock regulatory gene rpoH in Escherichia coli: involvement of a novel catabolite-sensitive promoter.

A catabolite-sensitive promoter was found to be involved in transcription of the heat shock regulatory gene rpoH encoding the sigma 32 protein. Expression of lacZ from the operon fusion, rpoHp-lacZ, was partially inhibited by glucose added to the broth medium. Dissection of the rpoH promoter region allowed us to localize the glucose-sensitive promoter to the 110-base-pair (bp) segment directly upstream of the rpoH coding region. Experiments on lacZ expression from the set of fusions in cya (adenylate cyclase) and crp (cyclic AMP [cAMP] receptor protein) mutants also supported the involvement of a catabolite-sensitive promoter. Analysis of rpoH mRNAs by S1 nuclease protection experiments led us to identify a novel promoter, designated P5, that is regulated by cAMP and the cAMP receptor protein. Studies of rpoH transcription in vitro demonstrated that RNA polymerase-sigma 70 can transcribe from the P5 promoter only in the presence of cAMP and its receptor protein. The 5' ends of P5 transcripts obtained in vivo and in vitro were found to be at 61 to 62 bp upstream of the initiation codon, and a putative binding sequence for the cAMP receptor protein was found at 38 to 39 bp further upstream. Transcription from the P5 promoter is increased by the addition of ethanol to the growth medium; however, the increase is greater in the presence of glucose than in its absence. These results add a new dimension to the transcriptional control of rpoH and to the regulation of the heat shock response in Escherichia coli.

Bacteriophage lambda↗
PubMed1989

[Infant botulism was confirmed in Ehime Prefecture].

The third case of infant botulism in Japan is reported. A four-month-old baby boy suddenly had weakness of suckling force, constipation and generalized hypotonicity. He was the product of normal gestation, labor and delivery. Growth and development were normal until he was nineteen weeks old. He received fruit-juice and honey daily. By bacteriological examination, Clostridium botulism type A was isolated from his feces and the honey which he had received. Type A toxin was detected from his feces but not from his serum.

Botulism↗
PubMed1989

Suppression of the Escherichia coli rpoH opal mutation by ribosomes lacking S15 protein.

Several suppressors (suhD) that can specifically suppress the temperature-sensitive opal rpoH11 mutation of Escherichia coli K-12 have been isolated and characterized. Unlike the parental rpoH11 mutant deficient in the heat shock response, the temperature-resistant pseudorevertants carrying suhD were capable of synthesizing sigma 32 and exhibiting partial induction of heat shock proteins. These strains were also cold sensitive and unable to grow at 25 degrees C. Genetic mapping and complementation studies permitted us to localize suhD near rpsO (69 min), the structural gene for ribosomal protein S15. Ribosomes and polyribosomes prepared from suhD cells contained a reduced level (ca. 10%) of S15 relative to that of the wild type. Cloning and sequencing of suhD revealed that an IS10-like element had been inserted at the attenuator-terminator region immediately downstream of the rpsO coding region. The rpsO mRNA level in the suhD strain was also reduced to about 10% that of wild type. Apparently, ribosomes lacking S15 can actively participate in protein synthesis and suppress the rpoH11 opal (UGA) mutation at high temperature but cannot sustain cell growth at low temperature.

Base Sequence↗