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H Yanagi

Publications and source records attributed to H Yanagi.

At least 73 records · Page 4Linked to original sources
PubMed1999

Heat-induced synthesis of sigma32 in Escherichia coli: structural and functional dissection of rpoH mRNA secondary structure.

The heat shock response in Escherichia coli depends primarily on the increased synthesis and stabilization of otherwise scarce and unstable sigma32 (rpoH gene product), which is required for the transcription of heat shock genes. The heat-induced synthesis of sigma32 occurs at the level of translation, and genetic evidence has suggested the involvement of a secondary structure at the 5' portion (nucleotides -19 to +247) of rpoH mRNA in regulation. We now present evidence for the mRNA secondary structure model by means of structure probing of RNA with chemical and enzymatic probes. A similar analysis of several mutant RNAs with a mutation predicted to alter a base pairing or with two compensatory mutations revealed altered secondary structures consistent with the expression and heat inducibility of the corresponding fusion constructs observed in vivo. These findings led us to assess the possible roles of each of the stem-loop structures by analyzing an additional set of deletions and base substitutions. The results indicated not only the primary importance of base pairings between the translation initiation region of ca. 20 nucleotides (the AUG initiation codon plus the "downstream box") and the internal region of rpoH mRNA but also the requirement of appropriate stability of mRNA secondary structures for characteristic thermoregulation, i.e., repression at a low temperature and induction upon a temperature upshift.

Base Sequence↗
PubMed1999

Differential and independent roles of a sigma(32) homolog (RpoH) and an HrcA repressor in the heat shock response of Agrobacterium tumefaciens.

The heat shock response in alpha proteobacteria is unique in that a combination of two regulators is involved: a positive regulator, RpoH (sigma(32) homolog), found in the alpha, beta, and gamma proteobacteria, and a negative regulator, HrcA, widely distributed in eubacteria but not in the gamma proteobacteria. To assess the differential roles of the two regulators in these bacteria, we cloned the hrcA-grpE operon of Agrobacterium tumefaciens, analyzed its transcription, and constructed deletion mutants lacking RpoH and/or HrcA. The DeltarpoH mutant and DeltarpoH DeltahrcA double mutant were unable to grow above 30 degrees C. Whereas the synthesis of heat shock proteins (e.g., DnaK, GroEL, and ClpB) was transiently induced upon temperature upshift from 25 to 37 degrees C in the wild type, such induction was not observed in the DeltarpoH mutant, except that GroEL synthesis was still partially induced. By contrast, the DeltahrcA mutant grew normally and exhibited essentially normal heat induction except for a higher level of GroEL expression, especially before heat shock. The DeltarpoH DeltahrcA double mutant showed the combined phenotypes of each of the single mutants. The amounts of dnaK and groE transcripts before and after heat shock, as determined by primer extension, were consistent with those of the proteins synthesized. The cellular level of RpoH but not HrcA increased significantly upon heat shock. We conclude that RpoH plays a major and global role in the induction of most heat shock proteins, whereas HrcA plays a restricted role in repressing groE expression under nonstress conditions.

Agrobacterium tumefaciens↗
PubMed1999

Prevalence of microalbuminuria and relationship to the risk of cardiovascular disease in the Japanese population.

The prevalence of microalbuminuria and its relationship to cardiovascular disease risk factors were examined in subjects participating in an annual physical and laboratory examination program. The urinary albumin concentration and the urinary albumin/creatinine ratio were determined in morning urine specimens. A turbidimetric immunoassay was used for the measurement of urinary albumin. Of the 731 subjects, 41 (5.6%) who were weakly positive or positive on a routine dipstick test for protein were excluded from the final analysis of data. Microalbuminuria was present in 14.5% of the men, in 12.4% of the women, and in 13.2% of the entire subject population when defined as a urinary albumin concentration of 30-299 microgram/ml. The prevalence of microalbuminuria was significantly higher in subjects with a high normal blood pressure (15.0%) or hypertension (26.2%) as compared with normotensive subjects (6.5%). Subjects with impaired glucose tolerance (24.3%) or hyperglycemic subjects (50.0%) had a significantly higher prevalence of microalbuminuria than normoglycemic subjects (11.3%). The prevalence of microalbuminuria was significantly higher in subjects with left ventricular hypertrophy (47.1%) as compared with those with normal electrocardiograms (11.3%). A good correlation was observed between urinary albumin concentration and albumin/creatinine ratio, and both showed a significant positive correlation with age, systolic and diastolic blood pressures, and fasting plasma glucose, total serum protein, albumin, and triglyceride levels, but not with angiotensin-converting enzyme activity. Multiple regression analysis demonstrated that both the urinary albumin concentration and the albumin/creatinine ratio show a significant positive correlation with systolic blood pressure and fasting plasma glucose. The prevalence of microalbuminuria was about 13% in this Japanese cohort, and the systolic blood pressure and the fasting plasma glucose level were demonstrated as independent risk indicators for both urinary microalbumin level and urinary microalbumin/creatinine ratio.

Adult↗
PubMed1999

Pentanucleotide repeat and size polymorphisms in the apolipoprotein(a) gene are associated with the lipoprotein(a) concentration in chronic hemodialysis patients.

The elevation of serum or plasma lipoprotein(a) [Lp(a)] levels is regarded as an independent risk factor for cardiovascular disease, and many previous reports demonstrated that Lp(a) levels in hemodialysis patients were significantly higher than in controls. The purpose of this study was to investigate the effect of a pentanucleotide repeat polymorphism [(TTTTA)n] in the 5'-flanking region of the apolipoprotein(a) [apo(a)] gene and of a size polymorphism of apo(a) for elevated Lp(a) concentrations observed in chronic hemodialysis patients. We studied 172 patients on chronic hemodialysis and 199 healthy adults. For analysis of the pentanucleotide repeat polymorphism, polymerase chain reaction products were loaded on polyacrylamide gel for electrophoresis. apo(a) size phenotyping was performed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. The median level of Lp(a) in the patients was 14.2 mg/dl which was significantly higher than that in controls (12.0 mg/dl; p < 0.05). In the genotype of (TTTTA)8/8, the median Lp(a) level in the patients (15.9 mg/dl) was significantly higher than that in controls (13.0 mg/dl; p < 0.05). In the genotype of (TTTTA)8/8 with large-sized apo(a) isoforms (A16-A25), the patients had significantly higher Lp(a) levels than the controls (p < 0.05). In conclusion, increased Lp(a) levels in chronic hemodialysis patients were mainly attributed to the combination of eight repeats of the pentanucleotide polymorphism and large-sized isoforms of apo(a).

Apolipoproteins A↗
PubMed1999

Association between serotonin transporter gene polymorphism and smoking among Japanese males.

The serotoninergic system may be involved in smoking behavior because nicotine increases brain serotonin secretion, nicotine withdrawal decreases serotonin levels, and a selective serotonin reuptake inhibitor antagonizes the response to nicotine. Compared with the L allele, the S allele of the polymorphism in the upstream regulatory region of the serotonin transporter gene is associated with decreased transcription efficiency of the 5-HTT gene promoter. We examined this polymorphism in a Japanese population consisting of 387 males from two different areas in Japan. The L allele was observed significantly more often in smokers (21%) than in nonsmokers (lifetime nonsmokers + ex-smokers, 14%; P = 0.005). The presence of the L allele (the L/L + L/S genotypes) was also significantly increased in smokers (37%) compared with that in nonsmokers (24%; P = 0.003). The present study suggests that individuals with the S/S genotype are less inclined to smoke and/or can more easily stop smoking than others, supporting a role of the serotoninergic system in smoking behavior.

Adult↗
PubMed1998

Identification of the cis-acting endoplasmic reticulum stress response element responsible for transcriptional induction of mammalian glucose-regulated proteins. Involvement of basic leucine zipper transcription factors.

When unfolded proteins accumulate in the endoplasmic reticulum (ER), transcription of glucose-regulated proteins (GRPs) representing ER-resident molecular chaperones is markedly induced via the unfolded protein response (UPR) pathway. In contrast to recent progress in the analysis of yeast UPR, both cis-acting elements and transactivators responsible for mammalian UPR have remained obscure. Here, we analyzed the promoter regions of human GRP78, GRP94, and calreticulin genes and identified a novel element designated the ER stress response element (ERSE). ERSE, with a consensus of CCAATN9CCACG, was shown to be necessary and sufficient for induction of these GRPs. Using yeast one-hybrid screening, we isolated a human cDNA encoding a basic leucine zipper (bZIP) protein, ATF6, as a putative ERSE-binding protein. When overexpressed in HeLa cells, ATF6 enhanced transcription of GRP genes in an ERSE-dependent manner, whereas CREB-RP, another bZIP protein closely related to ATF6, specifically inhibited GRP induction. Endogenous ATF6 constitutively expressed as a 90-kDa protein was converted to a 50-kDa protein in ER-stressed cells, which appeared to be important for the cellular response to ER stress. These results suggest that, as in yeast, bZIP proteins are involved in mammalian UPR, acting through newly defined ERSE.

Amino Acid Sequence↗
PubMed1998

Heat shock factor 1 mediates hemin-induced hsp70 gene transcription in K562 erythroleukemia cells.

Transcriptional induction of the hsp70 gene is mediated by heat shock factor 1 (HSF1) rapidly activated upon heat and other stresses. HSF2 has been thought to be responsible for accumulation of HSP70 during hemin-induced differentiation of human K562 erythroleukemia cells because of accompanying acquisition of HSF2 DNA binding activity. However, there has not been any direct evidence for such a functional role of HSF2. The purpose of this study is to clarify the roles of HSF1 and HSF2 in HSP70 induction in hemin-treated K562 cells. We show here that a chimeric polypeptide of HSF2 and GAL4 DNA binding domain (GAL4-BD-HSF2) was unable to induce a GAL4 binding site-containing luciferase reporter gene in response to hemin and that exogenously overproduced HSF2 also failed to increase expression of a heat shock element-containing reporter. On the contrary, expression of a GAL4-BD-HSF1 chimeric protein responded to hemin treatment as well as to heat shock, and transiently overexpressed HSF1 caused hemin-responsive induction of the reporter gene in a dose-dependent manner. These results indicate that HSF1, rather than HSF2, primarily mediates the hemin-induced transcription of the hsp70 gene.

Base Sequence↗
PubMed1998

Novel testis-specific protein that interacts with heat shock factor 2.

Although heat shock factor 2 (HSF2) binds to heat shock element (HSE) constitutively during differentiation, development and spermatogenesis, little is known about the nature and mechanism of transcriptional control of heat shock genes by HSF2. We screened a human testis cDNA library for proteins that can associate with HSF2 by the yeast two-hybrid system, and isolated clones encoding a novel protein, designated HSF2 binding protein (HSF2BP), that associates with HSF2 in vitro and in vivo and is specifically expressed in testis. The interaction seemed to occur between the trimerization domain of HSF2 and the amino terminal hydrophilic region of HSF2BP that comprises two leucine zipper motifs. HSF2BP may therefore be involved in modulating HSF2 activation in testis.

Amino Acid Sequence↗
PubMed1998

Function of the C-terminal transactivation domain of human heat shock factor 2 is modulated by the adjacent negative regulatory segment.

DNA binding of heat shock factor 2 (HSF2) is induced during hemin-induced differentiation of human erythroleukemia cell line K562. To identify the transcriptional activation and the regulatory domains of HSF2, we constructed a series of deletion derivatives fused to the yeast GAL4 DNA binding domain and analyzed their transactivation activity. A minimal transactivation domain of HSF2 was localized to the C-terminus (residues 472-536), as in HSF1, although amino acid sequence similarity for these regions was rather limited and the potential transactivation ability was about 25% that of HSF1. The transactivation mediated by this region of HSF2 was found to be negatively regulated by the adjacent 18 amino acid segment (residues 428-445) under normal conditions. Furthermore, the latter segment, when fused to the GAL4 activation domain, markedly inhibited GAL4 activity. Extract containing most derivatives of HSF2 retaining this segment exhibited doublet or triplet bands in gel mobility shift assays with heat shock element-containing DNA, suggesting possible involvement of some factors interacting with that segment in the negative regulation. Another putative transactivation domain and two negative regulatory regions were also localized within the internal region.

Amino Acid Sequence↗
PubMed1998

Palindrome with spacer of one nucleotide is characteristic of the cis-acting unfolded protein response element in Saccharomyces cerevisiae.

When unfolded proteins are accumulated in the endoplasmic reticulum (ER), an intracellular signaling pathway termed the unfolded protein response (UPR) is activated to induce transcription of ER-localized molecular chaperones and folding enzymes in the nucleus. In Saccharomyces cerevisiae, at least six lumenal proteins including essential Kar2p and Pdi1p are known to be regulated by the UPR. We and others recently demonstrated that the basic-leucine zipper protein Hac1p/Ern4p functions as a trans-acting factor responsible for the UPR. Hac1p binds directly to the cis-acting unfolded protein response element (UPRE) responsible for Kar2p induction. Moreover, we showed that the KAR2 UPRE contains an E box-like palindrome separated by one nucleotide (CAGCGTG) that is essential for its function. We report here that the promoter regions of each of five target proteins (Kar2p, Pdi1p, Eug1p, Fkb2p, and Lhs1p) contain a single UPRE sequence that is necessary and sufficient for induction and that binds specifically to Hac1p in vitro. All of the five functional UPRE sequences identified contain a palindromic sequence that has, in four cases, a spacer of one C nucleotide. This unique characteristic of UPRE explains why only a specific set of proteins are induced in the UPR to cope with ER stress.

Base Sequence↗
PubMed1998

Unconventional splicing of HAC1/ERN4 mRNA required for the unfolded protein response. Sequence-specific and non-sequential cleavage of the splice sites.

Accumulation of unfolded proteins in the endoplasmic reticulum (ER) activates an intracellular signaling pathway from the ER to the nucleus, termed the unfolded protein response. We and others recently identified transcription factor Hac1p/Ern4p responsible for the response in Saccharomyces cerevisiae and found that Hac1p expression is controlled by the regulated splicing of HAC1 mRNA. Walter and co-workers (Sidrauski, C., Cox, J. S., and Walter, P. (1996) Cell, 87, 405-413) further showed that the splicing requires tRNA ligase but not spliceosome. In this report, we carried out mutational analysis of HAC1 mRNA and revealed several unique features of the splicing. First, a mutation or deletion of the branchpoint-like sequence present in HAC1 intron did not affect the splicing. Second, cleavage of the splice sites was sequence-specific and thus completely blocked by some point mutations introduced at the 5' or 3' splice site. Third, cleavage of the 5' and 3' splice sites could occur independently as judged by the nature of splicing intermediates accumulated. Fourth, swapping the nucleotide sequences of the 5' and 3' splice sites inhibited the ligation but not the cleavage step. We conclude that signaling from the ER activates putative endonucleases that can carry out sequence-specific cleavage of the splice sites in a random order.

Alternative Splicing↗
PubMed1998

Usefulness of bipolar scissors for total colectomy.

PURPOSE: Total colectomy is frequently used in colorectal surgery. We evaluated the usefulness of bipolar scissors in this operation. METHODS: Twenty patients with ulcerative colitis underwent total colectomy at Hyogo College Hospital. Bipolar scissors were used in ten randomly chosen colectomies. The resected major vessels of the colonic mesentery were stained by hematoxylin and eosin. The bursting pressure of the artery weld was measured with a water-filled, open-tip catheter. RESULTS: Both number of ligations and operating time were reduced by use of bipolar scissors. The cut edge of the major artery was occluded by the weld created, with a mean bursting pressure of 213 (range, 175-250) mmHg. CONCLUSION: Use of bipolar scissors was safe and had the advantage of shortening the operating time by decreasing the number of clamping and ligating procedures.

Adolescent↗
PubMed1998

[A case of emergency surgery for acute mitral regurgitation due to complete papillary muscle rupture as complication of acute inferior myocardial infarction].

We experienced a case with acute mitral regurgitation caused by complete posterior papillary muscle rupture as complication of acute inferior myocardial infarction, who underwent successfully emergency operation of mital valve replacement and coronary revascularization in acute stage. A 64-year-old woman developed sudden cardiogenic shock shortly after the onset of acute inferior myocardial infarction. The diagnosis of acute inferior myocardial infarction was based on the electrocardiographic findings. Under IABP support, preoperative coronary angiography visualized total occlusion of segment 3 of the right coronary artery, and preoperative left ventriculography showed akinesis of inferior wall and severe mitral regurgitation. At 6 hours after onset of papillary muscle rupture, emergency operation was performed. At operation, posterior papillary muscle was found to be totally ruptured. Coronary artery revascularization and mitral valve replacement were performed. Postoperative course was uneventful, with 4 days of IABP and 5 days of ventilatory support. She was discharged on the twentieth postoperative day in NYHA class I. Reports of successful emergency operation for total papillary muscle rupture following acute myocardial infarction are rare. Early diagnosis and surgical treatment are mandatory to save this group of patients.

Emergencies↗
PubMed1998

Association of asthma and the interleukin-4 promoter gene in Japanese.

BACKGROUND: Susceptibility to the development of asthma and other atopic diseases is known to be associated with genetic components. Several investigator have linked the interleukin-4 (IL-4) gene and nearby markers located on chromosome 5 to atopy and asthma. Recent study has demonstrated that the T allele of a polymorphism in the IL-4 gene promoter region (C-590T) is associated with elevated levels of total serum IgE. OBJECTIVE: The objective of this study was to evaluate the possible role of this IL-4 polymorphism (C-590T) in modulating the allergic response and asthma in Japanese children. METHODS AND RESULTS: The study was conducted in two different populations: families ascertained through asthmatic children (asthmatic group, 306 members) in whom linkage of asthma and atopy to chromosome 5q31-33 is suggested and a random general population (control group, 215 members). The IL-4 C-590T polymorphism was genotyped by PCR-restriction fragment length polymorphism analysis. Frequency of the T allele was 0.73 in the asthmatic group and 0.70 in the control group. No significant difference in the levels of total serum IgE and specific IgE to house dust mite was observed between subjects with homozygote for the C allele, a heterozygote and a homozygote for the T allele by intrafamilial and interfamilial comparisons. Using the transmission disequilibrium test, however, we found a significantly frequent transmission of the T allele to asthmatic children (chi2=5.72, P=0.023). CONCLUSION: Our data suggest that the IL-4 promoter C-590T polymorphism may be associated with the development of asthma in Japanese children, but not through modulating total serum IgE levels.

Adolescent↗
PubMed1998

Chaperone coexpression plasmids: differential and synergistic roles of DnaK-DnaJ-GrpE and GroEL-GroES in assisting folding of an allergen of Japanese cedar pollen, Cryj2, in Escherichia coli.

Plasmids that can be used for controlled expression of the DnaK-DnaJ-GrpE and/or GroEL-GroES chaperone team were constructed in order to facilitate assessment of the effects of these chaperone teams on folding or assembly or recombinant proteins in Escherichia coli. A typical pACYC184-based plasmid which was obtained could express the major DnaK-DnaJ-GrpE and GroEL-GroES chaperone teams from separate promoters when L-arabinose and tetracycline, respectively, were added in a dose-dependent fashion. The model protein used to determine whether this system was useful was an allergen of Japanese cedar pollen, Cryj2, which was unstable when it was produced in E. coli K-12. The effects of chaperone coexpression on the folding, aggregation, and stability of Cryj2 were examined in the wild type and in several mutant bacteria. Coexpression of the DnaK-DnaJ-GrpE and/or GroEL-GroES chaperone team at appropriate levels resulted in marked stabilization and accumulation of Cryj2 without extensive aggregation. Experiments performed with mutants that lack each of the chaperone proteins (DnaK, DnaJ, GrpE, GroEL, and GroES) or heat shock transcription factor sigma 32 revealed that both chaperone teams are critically involved in Cryj2 folding but that they are involved in distinct ways. In addition, it was observed that the two chaperone teams have synergistic roles in preventing aggregation of Cryj2 in the absence of sigma 32 at certain temperatures.

Allergens↗
PubMed1998

Regulatory conservation and divergence of sigma32 homologs from gram-negative bacteria: Serratia marcescens, Proteus mirabilis, Pseudomonas aeruginosa, and Agrobacterium tumefaciens.

The heat shock response in Escherichia coli is mediated primarily by the rpoH gene, encoding sigma32, which is specifically required for transcription of heat shock genes. A number of sigma32 homologs have recently been cloned from gram-negative bacteria that belong to the gamma or alpha subdivisions of the proteobacteria. We report here some of the regulatory features of several such homologs (RpoH) expressed in E. coli as well as in respective cognate bacteria. When expressed in an E. coli delta rpoH strain lacking its own sigma32, these homologs activated the transcription of heat shock genes (groE and dnaK) from the start sites normally used in E. coli. The level of RpoH in Serratia marcescens and Pseudomonas aeruginosa cells was very low at 30 degrees C but was elevated markedly upon a shift to 42 degrees C, as found previously with E. coli. The increased RpoH levels upon heat shock resulted from both increased synthesis and stabilization of the normally unstable RpoH protein. In contrast, the RpoH level in Proteus mirabilis was relatively high at 30 degrees C and increased less markedly upon heat shock, mostly by increased synthesis; this sigma32 homolog was already stable at 30 degrees C, and little further stabilization occurred upon the shift to 42 degrees C. The increased synthesis of RpoH homologs in all these gamma proteobacteria was observed even in the presence of rifampin, suggesting that the induction occurred at the level of translation. Thus, the basic regulatory strategy of the heat shock response by enhancing the RpoH level is well conserved in the gamma proteobacteria, but some divergence in the actual mechanisms used occurred during evolution.

Agrobacterium tumefaciens↗
PubMed1998

A comparison of stapled and hand-sewn anastomoses in Crohn's disease.

Sixty-eight patients with Crohn's disease who underwent intestinal resection were randomly divided into 2 groups: the stapled group (32 patients, 40 anastomoses) with functional end-to-end anastomoses made with linear staplers and with circular stapling anastomoses, and the hand-sewn group (36 patients, 48 anastomoses), with anastomoses achieved by layer-to-layer suturing. There were no significant differences in operative indications, age, sex, blood loss, or length of hospital stay between the groups. The operation times for right hemicolectomy and total colectomy in the stapled group were significantly shorter than those in the hand-sewn group. There were no significant differences in anastomotic dehiscence or recurrence between the stapling and hand-sewn procedures. These results indicate that these stapling techniques, even though producing an everted anastomosis, are not an adverse procedure for Crohn's disease.

Adolescent↗