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Biomedical subjects

Masaho Ishino

Publications and source records attributed to Masaho Ishino.

15 recordsLinked to original sources
PubMed2005

Adenovirus E4orf6 targets pp32/LANP to control the fate of ARE-containing mRNAs by perturbing the CRM1-dependent mechanism.

E4orf6 plays an important role in the transportation of cellular and viral mRNAs and is known as an oncogene product of adenovirus. Here, we show that E4orf6 interacts with pp32/leucine-rich acidic nuclear protein (LANP). E4orf6 exports pp32/LANP from the nucleus to the cytoplasm with its binding partner, HuR, which binds to an AU-rich element (ARE) present within many protooncogene and cytokine mRNAs. We found that ARE-mRNAs, such as c-fos, c-myc, and cyclooxygenase-2, were also exported to and stabilized in the cytoplasm of E4orf6-expressing cells. The oncodomain of E4orf6 was necessary for both binding to pp32/LANP and effect for ARE-mRNA. C-fos mRNA was exported together with E4orf6, E1B-55kD, pp32/LANP, and HuR proteins. Moreover, inhibition of the CRM1-dependent export pathway failed to block the export of ARE-mRNAs mediated by E4orf6. Thus, E4orf6 interacts with pp32/LANP to modulate the fate of ARE-mRNAs by altering the CRM1-dependent export pathway.

Active Transport, Cell Nucleus↗
PubMed2005

Analysis of the prevalence of tetracycline resistance genes in clinical isolates of Enterococcus faecalis and Enterococcus faecium in a Japanese hospital.

Prevalence of seven tetracycline resistance (TC(R)) genes--tet(L), tet(M), tet(K), tet(O), tet(S), tet(T), and tet(U)--which are known to be distributed to gram-positive cocci was analyzed for 224 Enterococcus faecalis and 46 Enterococcus faecium clinical isolates obtained in a Japanese hospital. Any of the TC(R) genes was detected in 75.9% of all the enterococcal strains. The tet(M) was detected at highest rates in both E. faecalis (75.0%) and E. faecium (69.6%), followed by tet(L), which was harbored in 6.7% of E. faecalis isolates and 30.4% of E. faecium isolates. The tet(O), tet(S), and tet(T) were detected in E. faecalis at low frequencies mostly associated with tet(M), while tet(K) and tet(U) were not detected. Nucleotide sequences of tet(S) from E. faecalis strains were identical to that reported in Listeria monocytogenes. Sequences of tet(O) from two E. faecalis strains were almost identical to each other and also to those from Streptococcus pneumoniae, Streptococcus pyogenes, Streptococcus mutans, Campylobacter jejuni, and Campylobacter coli, although minor sequence divergence was observed. The tet(T), which had been reported only in Streptococcus pyogenes, was found in five E. faecalis strains. Sequence of the enterococcal tet(T) differed from that of S. pyogenes by only four nucleotides (four amino acids) and showed high sequence identity (99.8%, amino acid level). Enterococcal strains with any one TC(R) gene or those with two TC(R) genes showed generally similar MICs of tetracyclines, and no evident difference in resistance level was observed.

Amino Acid Sequence↗
PubMed2005

Genetic analysis of mec A homologues in Staphylococcus sciuri strains derived from mastitis in dairy cattle.

Methicillin-resistant Staphylococcus aureus (MRSA) is defined by the presence of the mec A gene, which is considered to have been transferred horizontally from unknown bacterial species to S. aureus. As a candidate of evolutionary precursor of the mec A, the mec A-like gene (mec A homologue), which is ubiquitously present in Staphylococcus sciuri has been proposed. In this study, sequences of the mec A homologue in four S. sciuri strains (SCBM 1-SCBM 4) derived from dairy cows were determined to analyze their genetic characteristics and relatedness to mec A and the mec A homologue reported so far. The mec A-like gene sequences of the four S. sciuri strains were identical with each other and were considered to encode a product comprising 665 amino acids that is one amino acid smaller in size than products of mec A-like gene reported previously for S. sciuri strains K1, K1 1, and K3 (mec A1). The mec A homologue of a representative strain SCBM 1 showed 79.3--79.8% sequence identity to MRSA mec A and 93.4--94.4% identity to mec A homologues reported for the three S. sciuri strains. Between S. sciuri strain SCBM 1 and strains K1, K1 1, or K3, amino acid sequence identities in transpeptidase domain of the mec A-like gene product (98.2--98.5%) were higher than those in the transglycosylase domain (92.1--94.3%). In addition, SCBM 1 showed extremely high sequence identities of hsp 60, sodA, and rpoB genes (more than 98.7%) to S. sciuri strains, while showing 70.3--94.2% identity of these genes to other staphylococcal species. These findings indicated that mec A homologues in S. sciuri may be genetically more divergent than mec A in MRSA and methicillin-resistant coagulase-negative staphylococci.

Amino Acid Sequence↗
PubMed2005

Detection of a novel aph(2") allele (aph[2"]-Ie) conferring high-level gentamicin resistance and a spectinomycin resistance gene ant(9)-Ia (aad 9) in clinical isolates of enterococci.

Aminoglycoside-modifying enzymes (AMEs) are major factors that confer aminoglycoside resistance to enterococci. In an epidemiologic study on distribution of 12 AME genes in 534 recent clinical strains isolated from a Japanese hospital, two uncommon AME genes, ant(9)-Ia and a novel aph(2") allele, aph(2")-Ie, were detected. ant(9)-Ia had been reported only in Staphylococcus aureus and encodes spectinomycin adenylyltransferase ANT(9)-I, which confers resistance to spectinomycin. The ant(9)-Ia gene was detected in three strains, a single strain each of Enterococcus faecalis, E. faecium, and E. avium. Nucleotide sequences of ant(9)-Ia from these three enterococcal species were identical to that reported for S. aureus and considered to be located on Tn 554. The new aph(2") allele, designated aph(2")-Ie, was identified in three E. faecium strains. The aph(2")-Ie allele was genetically close to aph(2")-Id reported in E. casseliflavus (93.7% amino acid sequence identity; 96.3% similarity), while distant from aph(2")-Ia, aph(2")-Ib, or aph(2")-Ic (26.3-29.5% amino acid sequence identity). Sequence divergence between APH(2")-Id and APH(2")-Ie was mostly located in amino-terminal half. In contrast, sequences corresponding to the three motifs required for aminoglycoside phosphotransferase were conserved except for a single amino acid. Three E. faecium strains having aph(2")-Ie showed high-level resistance to gentamicin and streptomycin, but not to kanamycin, dibekacin, and tobramycin, unlike enzyme specificity described for aph(2")-Id in E. casseliflavus. Such a difference in resistance phenotype was suggested to be related to amino acid sequence divergence between APH(2")-Id and APH(2")-Ie.

Alleles↗
PubMed2004

Genetic analysis of group B human rotaviruses detected in Bangladesh in 2000 and 2001.

Group B rotaviruses detected in Bangladesh in 2000 and 2001 were analyzed genetically to clarify relatedness to human group B rotaviruses reported previously in China and India, and to animal group B rotaviruses. VP7 gene sequences of the Bangladeshi group B rotaviruses (Bang373, Bang544, Bang334, and Bang402) were almost identical to each other and also showed high sequence identity to the Indian strain CAL-1 (98%) and Chinese strain adult diarrhea rotavirus (ADRV) (92%), while identities to bovine and murine viruses were considerably low (60-63%). Other genes of Bang373 and Bang544 encoding VP2, VP4, VP6, and NSP1 through NSP5 also showed much higher sequence identities to those of CAL-1 (97.7-99.4%) than to those of ADRV (89.9-93.9%). Characterization of nucleotide substitutions among Bang373, CAL-1, and ADRV suggested that all the gene segments might have evolved neutrally at similar mutation rates, while some of the gene segments (e.g., VP2 gene) were suggested to be more conserved than others. In conclusion, group B rotaviruses detected in Bangladesh represented by Bang373 and the Indian virus CAL-1 were considered as virtually identical viruses which are distinct genetically from ADRV, and it was suggested that Bang373 (CAL-1)-like group B rotavirus (Bengali strains) might be distributed primarily in an area around the Bay of Bengal.

Adult↗
PubMed2004

Phylogenetic analysis of a human group B rotavirus WH-1 detected in China in 2002.

A human group B rotavirus strain WH-1 was detected in an adult sporadic case of diarrhea in Wuhan, China in 2002. In this study, the gene sequences of WH-1 were determined in order to examine the phylogenetic relatedness to other human group B rotaviruses found previously in China (ADRV, in 1982), India (CAL-1, in 1998), and Bangladesh (Bang373, in 2000), as well as animal viruses, and to estimate the mutation rate of group B rotavirus. VP7 (major outer capsid protein) gene of WH-1 showed extremely high sequence identity (98.6%) to ADRV and showed relatively high sequence identities to CAL-1 (92.5%) and Bang373 (92.4%). In contrast, identities to animal (bovine and murine) group B rotaviruses were considerably lower (61-64%). Other gene segments of WH-1 encoding VP2, VP4, VP6, NSP1-NSP3, and NSP5 also showed high sequence identities to ADRV genes (98-99%), which were generally higher than those to CAL-1 genes and Bang373 genes (90-95%). However, amino acid sequence identities between WH-1 and ADRV were almost the same (VP2, VP6, and NSP3), or lower (NSP2) than those between WH-1 and CAL-1 (or Bang373). Since rates of synonymous substitution and transition between WH-1 and ADRV were similar for all the segments analyzed, genetic evolution was considered to have occurred neutrally and at a similar speed in most of the RNA segments. Based on the sequence divergence between WH-1 and ADRV, the mutation rate in natural condition of human group B rotavirus was estimated as 7.9 x 10(-4) substitution/site per year. The frequency of synonymous substitution between ADRV and Bang373 was 5.7 times higher than that between ADRV and WH-1, suggesting that the group B rotaviruses of Indian-Bangladeshi lineage diverged from that of Chinese lineage several decades ago.

Adult↗
PubMed2003

CrkL directs ASAP1 to peripheral focal adhesions.

Searching for proteins in platelets that can interact with the N-terminal SH3 domain of CrkL (using a combination of a pull-down assay followed by mass spectrometry), we have found that human platelets express an ADP-ribosylation factor (Arf)-specific GTPase-activating protein (GAP), ASAP1, as a CrkL-binding protein. In spreading platelets, most endogenous ASAP1 is localized at peripheral focal adhesions. To determine the physiologic significance of the CrkL-ASAP1 association, we overexpressed CrkL, ASAP1, or both in combination in COS7 cells. Unlike endogenous ASAP1 in platelets, overexpressed ASAP1 showed diffuse cytoplasmic distribution. However, when co-expressed with wild-type CrkL, both endogenous and expressed ASAP1 accumulated at CrkL-induced focal adhesions. An SH2-mutated CrkL, which cannot localize at focal adhesions, failed to recruit ASAP1 into focal adhesions. Thus, CrkL appears to be a lynchpin between ASAP1 and peripheral focal adhesions.

Adaptor Proteins, Signal Transducing↗
PubMed2003

Analysis of genomic diversity and evolution of the low-level antiseptic resistance gene smr in Staphylococcus aureus.

A multidrug efflux pump specified by the smr gene mediates low-level antiseptic resistance in staphylococci. We analyzed the genomic diversity of smr and its gene cassette, a structural unit containing smr and terminal direct repeats (DRs), in 22 clinical strains of Staphylococcus aureus isolated over 9 years in a Japanese hospital. Although open reading frames (ORFs) of all the smr genes examined were identical to those reported previously (e.g., qacD in pSK41), smr gene cassettes were classified into three groups (types 1, 2, and 3). The type 1 cassette had an identical genetic organization to that found in the plasmid pSK41, a putative prototype of the smr gene cassette, which contains DRs flanking smr. In the type 2 cassette, the rep gene and a putative replication nick site were found upstream of smr, between a SSOA (single-strand origin) sequence and DR1c, which are components of the type 1 cassette DR. In the type 3 cassette detected in a single strain, IS431 was located between the 3' end of smr and DR. It was suggested by genomic comparison that type 2 and type 3 cassettes might have been derived from the type 1 cassette via insertion of foreign DNA sequence, and that the type 2 cassette might be a precursor form of some previously reported smr cassettes, such as those in pSK108 and pNVH99. Although MICs of antiseptics and ethidium bromide were generally the same among strains having type 1, 2, or 3 smr gene cassette, the type 1 cassette was detected most frequently. Moreover, the copy number of the smr gene in the type 2 cassette was found to be much higher than that in the type 1 or type 3 cassette.

Anti-Bacterial Agents↗
PubMed2002

Nuclear translocation of cell adhesion kinase beta/proline-rich tyrosine kinase 2.

Cell adhesion kinase beta (CAKbeta/PYK2) is a protein-tyrosine kinase of the focal adhesion kinase (FAK) family. Whereas FAK predominantly localizes at focal adhesions, CAK beta localizes at the perinuclear region in fibroblasts. Here we expressed in cultured cells two point mutants of CAKbeta, P717A and P859A, each of which had lost one of its two PXXP motifs, the ligand sequence for SH3 domains, found at the CAKbeta C-terminal region. We observed a remarkable change in the subcellular distribution of the P859A mutant; while that of the P717A mutant was the same as the wild type. The P859A mutant localized exclusively in the cell nucleus in all cell lines examined. Wild-type CAKbeta also accumulated in the nucleus when cells were treated with an inhibitor of the nuclear export of proteins. These results indicate that CAK beta shuttles between the cytoplasm and the nucleus. On nuclear accumulation of P859A-CAKbeta, a CAKbeta-binding protein, Hic-5, also accumulated in the nucleus. P859A-CAKbeta and co-expressed Hic-5 formed nuclear speckles, in which one other CAK beta-binding protein, p130(Cas), was also concentrated. These findings on nuclear translocation of CAK beta imply that CAKbeta may regulate nuclear processes such as transcription, particularly because Hic-5 was recently shown to be a coactivator of nuclear receptors.

Active Transport, Cell Nucleus↗