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Biomedical subjects

I Matsuoka

Publications and source records attributed to I Matsuoka.

At least 19 recordsLinked to original sources
PubMed2005

Effects of sex steroids on expression of adenylyl cyclase messenger RNA in rat uterus.

The aim of our study was to investigate the effects of estradiol (E2) and/or progesterone (P4) bilateral ovariectomized rats on gene expressions of adenylyl cyclases (AC2, AC4, AC6, AC9). Non-pregnant (NP) Wister rats (between post-natal 10 and 12 weeks) and normal pregnant rats (between postnatal 10 and 14 weeks) were used. NP rats were divided into five groups: 1) control NP rats, 2) ovariectomy rats (OVX), 3) OVX injected with E2 (6 microg) for 4 days (E2), 4) OVX injected with P4 (5 mg) for 4 days (P4), 5) ovariectomy rats injected with E2 (6 microg) and P4 (5 mg) for 4 days (E2/P4). The ovariectomized rats were sacrificed by anesthesia of diethyl ether after 24 h from the last injection. The pregnant group was sacrificed in the same way on 14 (P14), 17 (P17) and 21 (P21) of pregnancy, because the days between P14 and P17 were the second trimester of pregnancy and P21 was the third trimester. Total RNA were prepared from the uteri of each subject, and expression of ACs was analyzed by reverse transcription-polymerase chain reaction (RT-PCR). Expression of mRNAs for AC2, AC4, AC6 and AC9 were maximally increased on P17 and then decreased on P21. In OVX rats, expression of mRNAs for AC2, AC4, and AC9 were decreased as compared to NP. AC2 mRNA was significantly increased by E2 treatment. AC4 and AC9 mRNA was significantly increased by injection of E2 or P4. AC6 mRNA level was not affected by E2 and/or P4. In conclusion, AC2, AC4 and AC9 gene expression is affected by estrogen and/or P4. On the contrary, AC6 gene expression was not changed by OVX or hormone treatment. Since, all ACs mRNA examined here are increased during pregnancy, AC6 may be affected by other factor(s) other than estrogen and P4.

Adenylyl Cyclases↗
PubMed2004

Identification and characterization of novel developmentally regulated neural-specific proteins, BRINP family.

Processes of neuronal differentiation involve activation of a set of neuronal specific genes and cessation of cell proliferation in postmitotic neurons. Previous studies revealed that bone morphogenetic protein (BMP) and retinoic acid (RA) play important roles in the differentiation of peripheral sympathetic neurons such as the synergistic induction of responsiveness to specific neurotrophic factors. In the present study, while trying to clarify the mechanism of the BMP/RA-actions, we identified a novel neural-specific protein, BMP/RA-inducible neural-specific protein-1 (BRINP1) which shows no similarity to other known proteins. Subsequently, two homologous proteins, BRINP2 and BRINP3, making up the BRINP family, are identified. Individual BRINP genes have distinct regulatory mechanisms of expression within the nervous system. In rodent brain, BRINP1 is expressed from earlier developmental stage, i.e. E9.5, and widely expressed in various neuronal layers and nuclei of the adult animal, while BRINP2 and BRINP3 were detectable from E11.5 and expressed in rather limited regions in a complementary manner. During the course of perinatal development of sympathetic neurons, BRINP1 is induced from earlier embryonic stage and further increased toward adult stage, while BRINP3 expressed from earlier stage is replaced by BRINP2 expression which increases postnatally in accordance with the action of BMP2 and RA. Furthermore, when expressed in nonneuronal cells, all three BRINP family proteins suppressed the cell cycle progression. Possible physiological functions of BRINP family members in the development of the nervous system are discussed.

Amino Acid Sequence↗
PubMed2001

Inhibitory effect of 2,3-butanedione monoxime (BDM) on Na(+)/Ca(2+) exchange current in guinea-pig cardiac ventricular myocytes.

1. The effect of 2,3-butanedione monoxime (BDM), a 'chemical phosphatase', on Na(+)/Ca(2+) exchange current (I(NCX)) was investigated using the whole-cell voltage-clamp technique in single guinea-pig cardiac ventricular myocytes and in CCL39 fibroblast cells expressing canine NCX1. 2. I(NCX) was identified as a current sensitive to KB-R7943, a relatively selective NCX inhibitor, at 140 mM Na(+) and 2 mM Ca(2+) in the external solution and 20 mM Na(+) and 433 nM free Ca(2+) in the pipette solution. 3. In guinea-pig ventricular cells, BDM inhibited I(NCX) in a concentration-dependent manner. The IC(50) value was 2.4 mM with a Hill coefficients of 1. The average time for 50% inhibition by 10 mM BDM was 124+/-31 s (n=5). 4. The effect of BDM was not affected by 1 microM okadaic acid in the pipette solution, indicating that the inhibition was not via activation of okadaic acid-sensitive protein phosphatases. 5. Intracellular trypsin treatment via the pipette solution significantly suppressed the inhibitory effect of BDM, implicating an intracellular site of action of BDM. 6. PAM (pralidoxime), another oxime compound, also inhibited I(NCX) in a manner similar to BDM. 7. Isoprenaline at 50 microM and phorbol 12-myristate 13-acetate (PMA) at 8 microM did not reverse the inhibition of I(NCX) by BDM. 8. BDM inhibited I(NCX) in CCL39 cells expressing NCX1 and in its mutant in which its three major phosphorylatable serine residues were replaced with alanines. 9. We conclude that BDM inhibits I(NCX) but the mechanism of inhibition is not by dephosphorylation of the Na(+)/Ca(2+) exchanger as a 'chemical phosphatase'.

Adenosine Triphosphate↗
PubMed2001

Beta,gamma-methylene ATP-induced cAMP formation in C6Bu-1 cells: involvement of local metabolism and subsequent stimulation of adenosine A2B receptor.

The mechanism underlying beta,gamma-methylene ATP (beta,gamma-MeATP)-induced cAMP elevation was investigated in rat glioma C6Bu-1 cells. Beta,gamma-MeATP increased forskolin-stimulated cAMP formation in a manner sensitive to both the P1 antagonist xanthine amine congener (XAC) and the P2 antagonist pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS). Adenosine deaminase (ADA; 1 U/mL), which abolished the adenosine-induced response, did not eliminate the beta,gamma-MeATP-induced response. However, combination of ADA with alpha,beta-methylene ADP (alpha,beta-MeADP), an ecto-5'-nucleotidase inhibitor, blocked the beta,gamma-MeATP-induced response. AMP, the substrate for ecto-5'-nucleotidase, also induced cAMP formation in a manner sensitive to XAC and alpha,beta-MeADP inhibition. However, the AMP-induced response was not blocked by PPADS. HPLC analyses revealed that adenosine was generated from beta,gamma-MeATP and AMP. In addition, alpha,beta-MeADP inhibited the conversion of beta,gamma-MeATP and AMP to adenosine, whereas PPADS blocked adenosine formation from beta,gamma-MeATP but not from AMP. [3H]Adenosine generated from [3H]AMP was preserved on the cell surface environment even in the presence of ADA. The mRNAs for ecto-phosphodiesterase/pyrophosphatase 1 (EC 3.1.4.1), ecto-5'-nucleotidase (EC 3.1.3.5) and adenosine A2B receptor were detected by RT-PCR. These results suggest that C6Bu-1 cells possess ecto-enzymes converting beta,gamma-MeATP to adenosine, and the locally accumulated adenosine in this mechanism efficiently stimulates A2B receptors in a manner resistant to exogenous ADA.

5'-Nucleotidase↗
PubMed2001

Inhibition of Ras extracellular-signal-regulated kinase (ERK) mediated signaling promotes ciliary neurotrophic factor (CNTF) expression in Schwann cells.

Ciliary neurotrophic factor (CNTF) can prevent injury-induced motor neuron death. However, it is also evident that expression of CNTF in Schwann cells is suppressed during nerve regeneration. In this report, we have addressed the mechanism underlying the down-regulation of CNTF expression in injured nerves using a mouse Schwann cell line IMS32 and mouse sciatic nerve. In IMS32 cells, activation of the Ras extracellular-signal-regulated kinase (ERK) pathway by adenoviral vector-mediated expression of dominant active MEK1 did not alter a basal level of CNTF expression, whereas inhibition of the Ras-ERK pathway by using adenoviral vectors resulted in a marked increase in CNTF expression. This inverse relation between before and after axotomy was also observed in mouse sciatic nerve. In the axotomized sciatic nerve, the phosphorylated ERK was markedly increased; in contrast, the expression of CNTF was markedly decreased. These findings suggest that an inactive state of ERK is crucial for the CNTF expression in Schwann cells, and that activation of ERK following nerve injury critically influences the expression of CNTF. This might well explain why CNTF is highly expressed in quiescent Schwann cells in the peripheral nervous system, and also why CNTF is not abundant in axotomized nerves or cultured Schwann cells in which the proliferation signal is obviously active.

Adenoviridae↗
PubMed2001

Qualitatively different response of isolated rabbit aorta to methylene blue administered from intimal and adventitial surface.

An isolated rabbit aortic preparation, on which administered drugs act selectively from intimal or adventitial surface, was made. Epinephrine (0.1 nM approximately 10 microM) produced concentration-dependent increase of intraluminal pressure, which is due to increase of contraction of the vascular smooth muscle. Sensitivity of contractile response to epinephrine administered from intimal surface was significantly higher than that administered from adventitial surface. The contractile response to epinephrine administered from intimal surface was reduced by removal of the endothelium. Cocaine (100 microM) potentiated the contractile response to epinephrine administered from adventitial surface. Cocaine also potentiated the contractile response to high concentration of epinephrine administered from intimal surface, while the drug reduced the contractile response to low concentration of epinephrine. Methylene blue (100 microM) administered from adventitial surface produced a marked contraction, while methylene blue administered from intimal surface produced a marked relaxation. The relaxing response to methylene blue administered from intimal surface was reduced by the removal of endothelium. Prazosin (1 microM) suppressed the contractile response to methylene blue administered from adventitial surface, indicating that methylene blue released norepinephrine from adrenergic nerve terminals. The contractile response to epinephrine administered from intimal surface was reduced by methylene blue administered from intimal surface. The present study clearly demonstrated variation in mechanical response of isolated rabbit aortic preparation with intimal or adventitial surface of drug entry.

Animals↗
PubMed2000

Enhancement of sympathetic neuron survival by synergistic action of NT3 and GDNF.

Although roles of neurotrophin-3 (NT3) and glial cell line-derived neurotrophic factor (GDNF) are suggested for sympathetic neuron development, survival activity of either NT3 or GDNF alone on cultured embryonic rat sympathetic neurons is low (10-20%). We demonstrate that a combination of both NT3 and GDNF exerts a remarkable survival activity (85%). NT3 and GDNF did not affect expression levels of their receptors. However, stimulation with both NT3 and GDNF caused tyrosine-phosphorylation of Ret/GDNF-receptor at a level higher than that caused by GDNF alone. Furthermore, stimulation with both GDNF and NT3 induced an enhanced Thr308-phosphorylation of Akt kinase. These results suggest that the actions of NT3 and GDNF converge at the Ret/GDNF-receptor to enhance survival of the developing sympathetic neurons through activation of the phosphatidylinositol (PI) 3-kinase/Akt pathway.

Animals↗
PubMed2000

Regulation of glial cell line-derived neurotrophic factor responsiveness in developing rat sympathetic neurons by retinoic acid and bone morphogenetic protein-2.

There are several lines of evidence suggesting that, in addition to neurotrophins, member(s) of glial cell line-derived neurotrophic factor (GDNF) family play important roles in the development of sympathetic neurons. However, the mechanism regulating the responsiveness of the neurons to GDNF family members is not known. Previously, we reported on the cooperative roles of bone morphogenetic protein-2 (BMP2) and retinoic acid (RA) in the enhancement of neurotrophin-3 (NT3) responsiveness in cultured sympathetic neurons dissociated from perinatal rat superior cervical ganglia (SCG). In the present study, we further examined the effects of BMP2 and RA on the regulation of the responsiveness of SCG neurons to GDNF family members. Consequently, we found that RA alone induced the responsiveness of SCG neurons specifically to GDNF by upregulating the ligand-specifying receptor for GDNF (GFRalpha-1) at both the mRNA and protein levels. The expression levels of mRNAs for other ligand-specifying receptors for GDNF family (GFRalpha-2 and GFRalpha-3) were unaffected by RA. Although the upregulation of signal-transducing receptor Ret by the RA treatment was rather small, this treatment significantly increased the efficacy of tyrosine phosphorylation of Ret by GDNF. Experiments using synthetic retinoids suggested that RA acts through alpha-type of nuclear retinoic acid receptor to exert the induction of GDNF responsiveness. On the other hand, BMP2, which had no significant effect by itself on the GDNF responsiveness, promoted the action of RA to upregulate GFRalpha-1 and enhance the GDNF responsiveness. These results indicate that RA and BMP2 play important roles in the induction of GDNF responsiveness, as well as NT3 responsiveness, of developing SCG neurons.

Adrenergic Fibers↗
PubMed2000

Effects of P(1) and P2 receptor antagonists on beta, gamma-methyleneATP- and CGS21680-induced cyclic AMP formation in NG108-15 cells.

1. We have previously shown that ATP increased cyclic AMP in NG108-15 cells, which was inhibited by P(1) receptor antagonist methylxanthines. In the present study, we examined the effects of P(1) and P2 receptor antagonists on cyclic AMP formation induced by beta,gamma-methyleneATP (beta,gamma-MeATP) and CGS21680, an A(2A) adenosine receptor agonist, in NG108-15 cells. 2. beta,gamma-MeATP and CGS21680 increased intracellular cyclic AMP with EC(50) values of 8. 0+/-0.98 microM (n=4) and 42+/-7.5 nM (n=4), respectively. 3. Several P(1) receptor antagonists inhibited both beta,gamma-MeATP- and CGS21680-induced cyclic AMP increase with a similar rank order of potency; ZM241385>CGS15943>XAC>DPCPX. However, the pK(i) values of these antagonists for beta,gamma-MeATP were larger than those for CGS21680. 4. Alloxazine, a P(1) receptor antagonist, and several P2 receptor antagonists (PPADS, iPPADS, reactive blue-2) inhibited beta, gamma-MeATP-induced response, while these antagonists little affected CGS21680-induced one. Suramin was effective only for beta, gamma-MeATP-induced response at 1 mM. 5. 2-chloroadenosine (2CADO) and 2-chloroATP (2ClATP) increased cyclic AMP with similar potencies. The effects of these agonists were both inhibited by ZM241385, but only 2ClATP-induced response was inhibited by PPADS. 6. ATP- and beta, gamma-MeATP-induced responses were little affected by alpha, beta-methyleneADP, a 5'-nucleotidase inhibitor. 7. These results clearly demonstrate that ATP-stimulated cyclic AMP formation can be distinguished from the A(2A) receptor agonist-induced one by using the several P(1) and P2 receptor antagonists.

5'-Nucleotidase↗
PubMed2000

Effects of AMP derivatives on cyclic AMP levels in NG108-15 cells.

1. In NG108-15 neuroblastomaxglioma hybrid cells, ATP stimulates intracellular cyclic AMP formation, which is inhibited by both adenosine (P(1)) and P2 receptor antagonists. In the present study, we examined the effects of several AMP derivatives in NG108-15 cells and mouse neuroblastoma N18TG-2 cells. 2. Adenosine 2'-monophosphate (A2P), adenosine 3'-monophosphate (A3P) and adenosine 5'-phosphosulphate (A5PS) increased cyclic AMP levels with similar concentration-dependencies in NG108-15 cells. 3. Increases in cyclic AMP by AMP derivatives were inhibited by the P2 receptor antagonist PPADS, but not by suramin. Effects of AMP derivatives were also inhibited by P(1) receptor antagonists ZM241385, XAC, DPCPX and partially by alloxazine. The ecto-nucleotidase inhibitor alpha, beta-methyleneADP was without effect. 4. In contrast, AMP derivatives did not change cyclic AMP levels in N18TG-2 cells. Accumulation of cyclic AMP in N18TG-2 cells was stimulated by adenosine A(2) receptor agonists CGS21680 and NECA, but not by ATP or beta, gamma-methyleneATP, agonists for cyclic AMP production in NG108-15 cells. 5. Reverse transcription-coupled polymerase chain reaction (RT - PCR) analyses revealed that N18TG-2 cells express both A(2A) and A(2B) receptors, while NG108-15 cells express mainly A(2A) receptors. 6. AMP derivatives did not affect the P2X and P2Y receptors expressed in NG108-15 cells. 7. These results suggest that A2P, A3P and A5PS act as agonists for cyclic AMP production and that these compounds are valuable tools for determinating the mechanism of ATP-stimulated cyclic AMP response in NG108-15 cells.

5'-Nucleotidase↗
PubMed2000

Ecto-alkaline phosphatase in NG108-15 cells : a key enzyme mediating P1 antagonist-sensitive ATP response.

We previously demonstrated that extracellular adenine nucleotides induced cyclic AMP elevation through local adenosine production at the membrane surface and subsequent activation of adenosine A(2A) receptors in NG108-15 cells. Furthermore, the adenosine formation was found to be mediated by an ecto-enzyme distinct from the ecto-5'-nucleotidase (CD73). In this study, we investigated the properties of the ecto-AMP phosphohydrolase activity in NG108-15 cells. NG108-15 cells hydrolyzed AMP to adenosine with the K:(M:) value of 18.8+/-2.2 microM and V(max) of 5.3+/-1.6 nmol min(-1) 10(6) cells(-1). This activity was suppressed at pH 6.5, but markedly increased at pH 8.5. The AMP hydrolysis was blocked by levamisole, an alkaline phosphatase (ALP) inhibitor. NG108-15 cells released orthophosphate from 2'- and 3'-AMP as well as from ribose-5-phosphate and ss-glycerophosphate, indicating that NG108-15 cells express ecto-ALP. The cyclic AMP accumulation induced by several adenine nucleotides was inhibited by levamisole, p-nitrophenylphosphate and ss-glycerophosphate, with a parallel decrease in the extracellular adenosine formation. Reverse transcriptase polymerase chain reaction analysis revealed that NG108-15 cells express mRNA for the tissue-nonspecific isozyme of ALP. These results demonstrate that AMP phosphohydrolase activity in NG108-15 cells is due to ecto-ALP, and suggest that this enzyme plays an essential role for the P1 antagonist-sensitive ATP-induced cyclic AMP accumulation in NG108-15 cells.

Adenosine↗
PubMed2000

Seasonal variation in heart rate variability in asthmatic children.

Asthma is a "seasonal disease" with symptoms either aggravated by environmental changes during specific seasons or prevalent at certain times of the year for other reasons. We examined whether the heart rate variability (HRV) of asthmatic children changes by season. The HRV during a portion of one night (00:00-04:00) and day (12:00-16:00) and the entire 24h period (00:00-24:00) during each of the four seasons was analyzed. The data of 95 children with asthma and 106 healthy children, as controls, were assessed. In children with asthma during the 24h period, seasonal variation in the low-frequency (LF) band (0.04-0.15 Hz) and the high-frequency (HF) band (0.15-0.4 Hz) were detected (HF: F=6.81, p=.0003; LF: F=4.18, p= .008). The HF value in the summer was significantly higher than in autumn and spring (Scheffe test: autumn vs. summer, s = 4.46, p < .001: spring vs. summer, s = 2.86, p < .05), while the LF value in autumn was significantly lower than in summer (s = 3.42, p < .01). In the control group, no seasonal variation in HF, LF, or LF/HF was detected. The findings infer the HRV, a surrogate measure of autonomic nervous system function, of asthmatic children is more susceptible to seasonal changes brought about by either endogenous annual rhythms or environmental weather phenomena.

Adolescent↗
PubMed2000

Analysis of promoter activity of 5'-upstream regions of zebrafish olfactory receptor genes.

The vertebrate olfactory system receives and discriminates a great variety of odorants. Many lines of evidence suggest that individual olfactory neuron expresses a single type or limited types of the olfactory receptor genes. However, the mechanism of selection of a single gene in the olfactory receptor family remains unclear. In the present study, we utilized zebrafish to identify the promoter element of the olfactory receptor genes in their 5'-upstream regions. First, we isolated a number of zebrafish olfactory receptor genes. These olfactory receptor genes were specifically expressed in the olfactory tissue as visualized by whole mount in situ hybridization analysis. Time of onset of the expression of each receptor clone varied from 24 h to 48 h postfertilization. Then, we injected various constructs containing the 5'-upstream regions of the olfactory receptor genes connected to beta-galactosidase reporter gene into fertilized zebrafish embryos. Constructs from two independent olfactory receptor genes exerted beta-galactosidase (promoter) activity that is specifically upregulated in the olfactory tissue. Use of either longer or deleted constructs of these two genes diminished the promoter activity in the olfactory tissue. From these results we discuss the mechanism of the transcription of the olfactory receptor genes in the olfactory neurons.

Amino Acid Sequence↗
PubMed2000

Identification of basic fibroblast growth factor-responsive genes by mRNA-differential display in an immortalized neural stem cell line.

Basic fibroblast growth factor (bFGF) has been shown to stimulate proliferation and differentiation of neural stem cells through regulation of gene expressions. To clarify the roles of bFGF during early neurogenesis, we performed a series of differential display with mRNAs from an immortalized neural stem cell line treated with bFGF for different periods. We isolated ten independent cDNAs whose mRNA levels were regulated by bFGF. Some of these cDNA were identical to known genes, including calmodulin and thrombospondin 1, while others were unknown genes. One of these unknown genes up-regulated by bFGF (clone 2C) was specifically expressed in the brain among various rat tissues. It is expected that further analysis of clone 2C will reveal important roles of bFGF in the regulation of brain development.

Animals↗
PubMed2000

Correlation between adenine nucleotide-induced cyclic AMP elevation and extracellular adenosine formation in NG108-15 cells.

We previously demonstrated that extracellular adenine nucleotides induced cyclic AMP elevation in NG108-15 cells. This response was resistant to adenosine deaminase (ADA) and the ecto-5'-nucleotidase (CD73) inhibitor alpha,beta-methylene ADP (alpha,beta-MeADP), but was inhibited by both P1- and P2-receptor antagonists. In the present study, we investigated the relationship between adenine nucleotide-induced cyclic AMP elevation and extracellular adenosine formation. ATP, AMP and beta,gamma-methylene ATP (beta,gamma-MeATP) were time-dependently metabolized to adenosine in NG108-15 cells. Adenosine formations from ATP, AMP and beta,gamma-MeATP were not affected by alpha,beta-MeADP, but suppressed by the P2-receptor antagonist pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS). A close correlation between extracellular adenosine formation and cyclic AMP increasing effects were obtained with several adenine nucleotide agonists in NG108-15 cells as well as their parent cell line C6Bu-1 and N18TG-2 cells, all of which possess functional adenosine A2 receptors. When NG108-15 cells were incubated with [3H]ATP or [3H]AMP in the presence of ADA, [3H]adenosine was found to distribute dominantly on the cell surface. NG108-15 cells expressed mRNA for the ecto-ATPase and nucleotide pyrophosphatase, but not for CD73. These results suggest that local adenosine formation by an ecto-enzyme distinct from CD73 is involved in adenine nucleotide-induced cyclic AMP formation in NG108-15 cells.

Adenine Nucleotides↗
PubMed1999

No requirement of P2X1 purinoceptors for platelet aggregation.

ADP produces a series of responses in rabbit platelets such as shape changes, aggregation and intracellular Ca2+ mobilization. In human platelets, the P2X1 receptor mediates a rapid increase in intracellular Ca2+ concentration ([Ca2+]i) upon stimulation with ADP. We investigated whether this phenomenon is also present in rabbit platelets. We found that the P2X1 receptor-mediated response was absent because there was (1) no elevation of [Ca2+]i in response to alpha,beta-methylene-ATP, a selective P2X1 receptor agonist, in fura-2-loaded platelets; (2) no change in the ADP-induced [Ca2+]i increase and platelet aggregation after P2X1 receptor desensitization with alpha,beta-methylene-ATP; (3) complete inhibition of the ADP-induced [Ca2+]i elevation by the P2Y1 receptor specific antagonist, A3'P5'PS, with a similar ID50 value both in the presence and absence of external Ca2+. These results indicate that ADP-induced [Ca2+]i elevation is mainly mediated by P2Y1 receptors in rabbit platelets. We conclude that the P2X1 receptor does not play a significant role in the ADP-induced platelet shape changes and aggregation.

Adenosine Diphosphate↗
PubMed1999

A series of protein phosphatase gene disruptants in Saccharomyces cerevisiae.

Thirty-two protein phosphatase (PPase) genes were identified in the genome nucleotide sequence of Saccharomyces cerevisiae. We constructed S. cerevisiae disruptants for each of the PPase genes and examined their growth under various conditions. The disruptants of six putative PPase genes, i.e. of YBR125c, YCR079w, YIL113w, YJR110w, YNR022c and YOR090c, were created for the first time in this study. The glc7, sit4 and cdc14 disruptants were lethal in our strain background. The remaining 29 PPase gene disruptants were viable at 30 degrees C and 37 degrees C, but only one disruptant, yvh1, showed intrinsic cold-sensitive growth at 13 degrees C. Transcription of the YVH1 gene was induced at 13 degrees C, consistent with an idea that Yvh1p has a specific role for growth at a low temperature. The viable disruptants grew normally on nutrient medium containing sucrose, galactose, maltose or glycerol as carbon sources. The ppz1 disruptant was tolerant to NaCl and LiCl, while the cmp2 disruptant was sensitive to these salts, as reported previously, and none of the other viable PPase disruptants exhibited the salt sensitivity. When the viable disruptants were tested for sensitivity to drugs, i.e. benomyl, caffeine and hydroxyurea, ppz1 and ycr079w disruptants exhibited sensitivity to caffeine.

Benomyl↗