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Tetsuo Noda

Publications and source records attributed to Tetsuo Noda.

At least 55 records · Page 3Linked to original sources
PubMed2004

The corepressor mSin3A regulates phosphorylation-induced activation, intranuclear location, and stability of AML1.

The AML1 (RUNX1) gene, one of the most frequent targets of translocations associated with human leukemias, encodes a DNA-binding protein that plays pivotal roles in myeloid differentiation through transcriptional regulation of various genes. Previously, we reported that AML1 is phosphorylated on two serine residues with dependence on activation of extracellular signal-regulated kinase, which positively regulates the transcriptional activity of AML1. Here, we demonstrate that the interaction between AML1 and the corepressor mSin3A is regulated by phosphorylation of AML1 and that release of AML1 from mSin3A induced by phosphorylation activates its transcriptional activity. Furthermore, phosphorylation of AML1 regulates its intranuclear location and disrupts colocalization of AML1 with mSin3A in the nuclear matrix. PEBP2 beta/CBF beta, a heterodimeric partner of AML1, was shown to play a role in protecting AML1 from proteasome-mediated degradation. We show that mSin3A also protects AML1 from proteasome-mediated degradation and that phosphorylation-induced release of AML1 from mSin3A results in degradation of AML1 in a time-dependent manner. This study provides a novel regulatory mechanism for the function of transcription factors mediated by protein modification and interaction with cofactors.

Animals↗
PubMed2004

Prevention of gastrointestinal tumors based on adenomatous polyposis coli gene mutation by dendritic cell vaccine.

Here we describe the effect of immunization with dendritic cells loaded with syngeneic tumor cells (DC/Ts) by polyethylene glycol treatment, on tumor development in adenomatous polyposis coli (APC) gene mutant mouse models, APC1309 and APC(Min-/+), in which adenomatous polyps of the gastrointestinal tracts develop with a high incidence. Treatment with DC/Ts prevented the development of gastrointestinal tumors, and coadministration of DC/Ts and IL-12 caused a further reduction in tumor incidence. Splenocytes from APC1309 mice treated with DC/Ts and IL-12 showed no cytotoxic activity toward the tumor cells, but serum antibody specific to them was detected. IgG from the treated mice exhibited cytotoxic activity against the tumor cells in vitro. Predominance of Th2 cell response over Th1 response was also suggested by ELISPOT assays in the treated mice. Depletion in vivo of CD4(+) T cells, not CD8(+) T cells, by the intraperitoneal administration of corresponding mAb's decreased the antitumor effect of DC/T inoculation. Immunofluorescence microscopic studies showed that Ig was attached to tumor cells in mice treated with DC/Ts and IL-12. These findings indicate that DC/T vaccination prevents tumor development through APC gene mutation and that its preventive effects are mediated by humoral antitumor immunity.

Animals↗
PubMed2004

Insulin receptor substrate 2 plays a crucial role in beta cells and the hypothalamus.

We previously demonstrated that insulin receptor substrate 2 (Irs2) KO mice develop diabetes associated with hepatic insulin resistance, lack of compensatory beta cell hyperplasia, and leptin resistance. To more precisely determine the roles of Irs2 in beta cells and the hypothalamus, we generated beta cell-specific Irs2 KO and hypothalamus-specific Irs2 knockdown (betaHT-IRS2) mice. Expression of Irs2 mRNA was reduced by approximately 90% in pancreatic islets and was markedly reduced in the arcuate nucleus of the hypothalamus. By contrast, Irs2 expression in liver, muscle, and adipose tissue of betaHT-IRS2 mice was indistinguishable from that of control mice. The betaHT-IRS2 mice displayed obesity and leptin resistance. At 4 weeks of age, the betaHT-IRS2 mice showed normal insulin sensitivity, but at 8 and 12 weeks, they were insulin resistant with progressive obesity. Despite their normal insulin sensitivity at 8 weeks with caloric restriction, the betaHT-IRS2 mice exhibited glucose intolerance and impaired glucose-induced insulin secretion. beta Cell mass and beta cell proliferation in the betaHT-IRS2 mice were reduced significantly at 8 and 12 weeks but not at 10 days. Insulin secretion, normalized by cell number per islet, was significantly increased at high glucose concentrations in the betaHT-IRS2 mice. We conclude that, in beta cells and the hypothalamus, Irs2 is crucially involved in the regulation of beta cell mass and leptin sensitivity.

Animals↗
PubMed2004

Abnormal sperm morphology caused by defects in Sertoli cells of Cnot7 knockout mice.

Cnot7 is a co-factor of transcription regulation, expressed in a variety of tissues including the lung, liver, thyroid gland, and testis. Our previous study (Nakamura et al., 2004) showed that deletion of the Cnot7 gene in mice caused almost no abnormal phenotypes except for male infertility, due to oligo-astheno-teratozoospermia. This study also showed that Cnot7-/- mouse germ cells transplanted as donors could colonize in recipient wild mouse testes to develop normal spermatogenesis by spermatogonial transplantation assay, suggesting that the abnormal spermatogenesis observed in the Cnot7-/- testes was induced by the impaired testicular microenvironment rather than a germ cell defect. In the present study, we have carried out reciprocal germ cell transplantation in which wild type germ cells were transplanted as donors into the recipient Cnot7-/- testes to evaluate the recipient microenvironment for supporting the spermatogenesis of donor cells. We noticed that donor cell colonization was less efficient in Cnot7-/- than in Cnot7+/- testes, and that the donor derived spermatids in the recipient Cnot7-/- testes showed severe deformities. These results support our previous report that Sertoli cell defects in the Cnot7-/- testes could induce oligo-astheno-teratozoospermia.

Animals↗
PubMed2004

Failure to assemble the peri-nuclear structures in GOPC deficient spermatids as found in round-headed spermatozoa.

Deletion of the GOPC gene encoding mouse GOPC (Golgi-associated PDZ- and coiled-coil motif-containing protein) causes infertile round-headed spermatozoa, which have acrosome-less round heads and deformed tails (Yao et al, 2002). This study investigated how GOPC deficient spermatids fail to assemble the peri-nuclear structures in round-headed spermatozoa during spermiogenesis in GOPC knockout mouse testes. In step 1-8 spermatids, Golgi-derived proacrosomal vesicles that are transported to the perinuclear region formed acrosome-like vesicles of various sizes, called pseudoacrosomes. The marginal ring of the acroplaxome, which is generally formed between the descending edge of a developing acrosome and nuclear envelope in a wild spermatid, was poorly formed between the pseudoacrosome and nuclear envelope. In step 9-11 elongating spermatids, a majority of pseudoacrosomes were detached from the nucleus and disappeared from the perinuclear region by spermiation. Concomitantly, several failures occurred on the nucleus, manchette, postacrosomal sheath (perinuclear theca), and posterior ring. Ectoplasmic specializations were poorly formed, and did not always associate with developing spermatids. Consequently, spermatid nuclear elongation to form round-headed spermatozoa developed was impaired. In addition to these sequential failures, the posterior ring deficiency was attributed to the tail deformation destined to occur during epididymal maturation as reported in an accompanying paper (Suzuki-Toyota et al, 2004 in this issue), its eventual phenotype being reminiscent of the round-headed spermatozoa of human infertile globozoospermia.

Adaptor Proteins, Signal Transducing↗
PubMed2004

The coiled tail of the round-headed spermatozoa appears during epididymal passage in GOPC-deficient mice.

Male mice deleting the gene encoding GOPC (Golgi-associated PDZ- and coiled-coil motif-containing protein) are infertile, showing globozoospermia with a coiled tail (Yao et al., 2002). We confirmed how and where tail anomalies were produced in spermatids and epididymal spermatozoa by light and electron microscopy. During spermiogenesis, tail formation occurred normally, but a defect was found at the posterior ring. Thereafter, remarkable sperm tail deformations were induced during epididymal passage. In the proximal caput epidiymidis, the tails remained normal and straight, but most of them coiled around the nucleus in the cauda epididymidis. Coiling is presumed to occur with the migration of the cytoplasmic droplet by the absence of the posterior ring. The connecting piece of the coiled tail was often dislocated or separated from the implantation fossa. Many mitochondria were separated from the outer dense fibers (ODFs) and formed a stratified mitochondrial sheath. Due to this, the distal part of the midpiece became bared of the mitochondrial sheath. The bared ODFs were often bent and disorganized. Tail deformities are attributed to weak or incomplete adhesion between the following structures: 1) plasma membrane and nuclear envelope at the posterior ring, 2) connecting piece and implantation fossa, and 3) mitochondria and ODFs. These defects result in a coiled tail, tail dislocation from the implantation fossa, and the stratified mitochondrial sheath accompanying bared ODFs in the midpiece, respectively. Thus the posterior ring is significant in preventing coiled tail formation. The GOPC-deficient spermatozoa provide a valuable model not only for head but also for tail anomalies.

Adaptor Proteins, Signal Transducing↗
PubMed2004

Conventional and array-based comparative genomic hybridization analyses of novel cell lines harboring HPV18 from glassy cell carcinoma of the uterine cervix.

We established 2 novel human cell lines (GCCOT-1, GCCRK) from glassy cell carcinoma. Both cell lines showed dual tendencies of glandular and squamous differentiation, and thus possess the characteristics resembling reserve cells, the putative origin of most carcinomas arising from the uterine cervix. HPV type 18 DNA including E6-E7, which is commonly found in cell types other than squamous cell carcinoma of uterine cervix, was detected in both cell lines. We analyzed gene copy number alterations of the 2 cell lines using conventional comparative genomic hybridization (CGH) coupled with array-based CGH. Among the putative oncogenes demonstrating copy number gain in both cell lines, FGR(SRC2) at 1p36.2-1 and LAMC2 at 1q25-31 have not been reported to show amplification in previous analyses of conventional cervical cell lines. These oncogenes are thus speculated to be directly associated with oncogenesis of glassy cell carcinoma. On the other hand, among the putative suppressor genes demonstrating copy number loss in both cell lines, the 9q region, ATM at 11q22.3, and CYLD at 16q12-13 have not been reported to show loss in conventional cervical cancer cell lines. These sites are speculated to be important as tumor suppressors directly associated with oncogenesis of glassy cell carcinoma. This study suggests for the first time that together with the presence of HPV type 18, alterations at the above sites are closely associated with oncogenesis of glassy cell carcinoma, a special type of carcinoma in the uterine cervix.

Adult↗
PubMed2003

Concomitant suppression of hyperlipidemia and intestinal polyp formation in Apc-deficient mice by peroxisome proliferator-activated receptor ligands.

Epidemiological studies have shown a positive association of colon cancer with hyperlipidemia. Furthermore, signaling generated by peroxisome proliferator-activated receptor (PPAR) alpha and gamma ligands, suggested to be candidate tumor preventive agents, has been shown to lower serum triglyceride levels. In the present study, we assessed hyperlipidemia in Apc-deficient mice, model animals for human familial adenomatous polyposis, and examined the effects of pioglitazone and bezafibrate, respectively, PPARgamma and PPARalpha agonists, on both hyperlipidemia and intestinal polyposis. Serum lipid levels in Apc(1309) mice and Min mice from 6 to 15 weeks of age were measured. Although serum levels of triglyceride and cholesterol were low in both Apc(1309) and wild-type mice at 6 weeks, triglycerides were elevated 10-fold in Apc(1309) mice by the age of 12 weeks but not in their wild-type counterparts. Cholesterol was also increased significantly, and marked centrilobular-restricted steatosis was observed in the livers of aged Apc(1309) mice. Similar findings were observed for Min mice at 15 weeks of age. Moreover, lipoprotein lipase mRNA levels in the liver and small intestine of Apc(1309) and Min mice were demonstrated to be lower than those in wild-type mice. Treatment of Apc(1309) mice with 100 and 200 ppm pioglitazone or bezafibrate for 6 weeks from 6 weeks of age caused dose-dependent reduction in serum triglycerides and cholesterol, along with reduction in the numbers of intestinal polyps to 67% of the control value. The present study clearly demonstrated a hyperlipidemic state in Apc gene-deficient mice and a potential of PPARalpha and PPARgamma ligands to suppress both hyperlipidemia and polyp formation. Hyperlipidemia in these mice may thus be associated with their intestinal lesion development.

Age Factors↗
PubMed2003

Cell proliferation in liver of Mmh/Ogg1-deficient mice enhances mutation frequency because of the presence of 8-hydroxyguanine in DNA.

The Mmh/Ogg1 gene product maintains the integrity of the genome by removing the damaged base 8-hydroxyguanine (8-OH-G), one of the major DNA lesions generated by reactive oxygen species. Using Ogg1-deficient mice, we sought to establish if cells having high amounts of 8-OH-G have the ability to proliferate and whether the mutation frequency increases after proliferation in vivo. When KBrO(3), a known renal carcinogen, at a dose of 2 grams/liter was administered to Ogg1 mutant mice for 12 weeks, the amount of 8-OH-G in liver DNA from treated Ogg1(-/-) mice increased 26.1 times that of treated Ogg1(+/+) mice. The accumulated 8-OH-G did not decrease 4 weeks after cessation of KBrO(3) treatment. Partial hepatectomy was performed on Ogg1(+/-) and Ogg1(-/-) mice after being treated with KBrO(3) for 12 weeks. The remnant liver from Ogg1(-/-) mice treated with KBrO(3) regenerated to the same extent as nontreated Ogg1(+/-) mice. In addition, 8-OH-G was not repaired during cell proliferation by partial hepatectomy, indicating that there is no replication coupled repair of preexisting 8-OH-G. The mutation frequency after the regeneration of liver from treated Ogg1(-/-) mice showed a 3.5-fold increase compared with before regeneration. This represents a mutation frequency 6.2 times that of normal levels. The proliferation of cells having accumulated amounts of 8-OH-G caused mainly GC-->TA transversions. These results showed that inactivation of the Ogg1 gene leads to a higher risk of cancer because cells with accumulated 8-OH-G still retain the ability to proliferate, leading to an increase in the mutation frequency.

Animals↗
PubMed2003

Requirement for 3-phosphoinositide-kependent dinase-1 (PDK-1) in insulin-induced glucose uptake in immortalized brown adipocytes.

To provide insight into the physiological importance of 3-phosphoinositide-dependent kinase-1 (PDK-1) in the metabolic actions of insulin, we have generated mice that harbor a PDK-1 gene containing LoxP sites (PDK-1(lox/lox) mice) and established immortalized brown preadipocyte cell lines both from these animals and from wild-type mice. Exposure to appropriate hormonal inducers resulted in the differentiation of >80% of the immortalized brown preadipocytes derived from both types of mice into mature adipocytes. Introduction of the Cre recombinase with the use of adenovirus-mediated gene transfer induced a dose-dependent decrease in the abundance of PDK-1 in PDK-1(lox/lox) adipocytes but not in the wild-type cells. In Cre-expressing PDK-1(lox/lox) adipocytes in which the abundance of PDK-1 was reduced by approximately 85%, the insulin-induced phosphorylation both of Akt on threonine 308 and of p70 S6 kinase on threonine-389 was markedly inhibited. The phosphorylation both of Akt on serine 473 and of p42 and p44 isoforms of mitogen-activated protein kinase induced by insulin was not affected by Cre expression, indicating that the latter specifically inhibits PDK-1-dependent signaling. Both glucose uptake and the translocation of glucose transporter 4 to the plasma membrane induced by insulin as well as glucose uptake induced by a constitutively active form of phosphoinositide 3-kinase were also greatly inhibited by Cre expression in PDK-1(lox/lox) adipocytes. Phosphorylation of AMP-activated protein kinase and glucose uptake induced by 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) were not affected by Cre expression in PDK-1(lox/lox) adipocytes. These results indicate that PDK-1 is essential for insulin-induced glucose uptake in adipocytes.

3-Phosphoinositide-Dependent Protein Kinases↗
PubMed2003

Mice lacking a transcriptional corepressor Tob are predisposed to cancer.

tob is a member of antiproliferative family genes. Mice lacking tob are prone to spontaneous formation of tumors. The occurrence rate of diethylnitrosamine-induced liver tumors is higher in tob(-/-) mice than in wild-type mice. tob(-/-)p53(-/-) mice show accelerated tumor formation in comparison with single null mice. Expression of cyclin D1 mRNA is increased in the absence of Tob and is reduced by Tob. Tob acts as a transcriptional corepressor and suppresses the cyclin D1 promoter activity through an interaction with histone deacetylase. Levels of tob mRNA are often decreased in human cancers, implicating tob in cancer development.

Animals↗
PubMed2003

ARF tumor suppressor induces mitochondria-dependent apoptosis by modulation of mitochondrial Bcl-2 family proteins.

A tumor suppressor gene product, ARF, sensitizes cells to apoptosis in the presence of appropriate collateral signals. In this study, we analyzed the mechanism of ARF-dependent apoptosis and demonstrated that ARF induces mitochondria-dependent apoptosis in p53 wild-type, ARF/p16-null cells. We also found that ARF evokes cytochrome c release from mitochondria, decreases mitochondrial membrane potential, and activates pro-caspase-9 to induce apoptosis. Our findings suggest that this apoptotic cellular modulation is brought about by up-regulation of the proapoptotic Bcl-2 family proteins Bax and Bim and down-regulation of antiapoptotic Bcl-2 in mitochondrial fractions. Additionally, ARF seems to down-regulate Bcl-2 in a p53-dependent manner while up-regulating Bax/Bim via a p53-independent pathway.

3T3 Cells↗
PubMed2003

Lymphoid enhancer factor 1 makes cells resistant to transforming growth factor beta-induced repression of c-myc.

The activation of lymphoid enhancer factor (LEF)/T-cell factor (TCF)-mediated transcription by sustained expression of beta-catenin and the loss of transforming growth factor beta (TGF-beta) signaling are essential steps in carcinogenesis, particularly for cancers of the colon, breast, and liver. The oncogene c-myc is a common target of both of these signaling pathways and a key regulator of cell cycle progression. Here we have identified a novel LEF/TCF-responsive element in the promoter of the human c-myc gene. beta-Catenin activated the transcriptional activity of the c-myc promoter by binding to this element in various cell lines. When TCF-4 was bound to this element, TGF-beta dissociated beta-catenin and repressed the transcriptional activity of the c-myc promoter. However, TGF-beta could not dissociate beta-catenin and could not repress c-myc transcription when LEF-1 was bound to the element instead of TCF-4. These findings suggest that enhanced expression of LEF-1, which occurs frequently in colon cancer, may make cells refractory to the down-regulation of c-myc and the subsequent growth arrest induced by TGF-beta.

3T3 Cells↗
PubMed2003

Lack of cholecystokinin-A receptor enhanced gallstone formation: a study in CCK-A receptor gene knockout mice.

The etiology of gallstones is multifactorial, with interactions between genes and the environment. We generated cholecystokinin (CCK) -A receptor (R)-deficient (-/-) mice and found that CCK did not produce gallbladder contraction in CCK-AR(-/-) mice. The purpose of this study was to identify the role of CCK-AR on gallstone formation. Age-matched CCK-AR gene (+/+) and (-/-) progenies were used. Sludge and gallstone formation, as well as plasma cholesterol levels, were measured at 12 and 24 months of age. Sludge and gallstone formation were significantly higher in CCK-AR(-/-) mice than in CCK-AR(+/+) mice at 12 and 24 months of age, although these were not different between 12 and 24 months of age. The plasma cholesterol levels, daily food intake, and body weight were not significantly different between CCK-AR(+/+) and (-/-) mice. Sludge and gallstone formation were not observed at 6 months of age. In conclusion, deteriorated gallbladder contraction due to a lack of CCK-AR favored gallstone formation after the middle age of life.

Animals↗
PubMed2003

Distinct macroscopic structures developed from solutions of chemical compounds and periodic proteins.

By controlling the growth of inorganic crystals, macro-biomolecules, including proteins, play pivotal roles in modulating biomineralization. Natural proteins that promote biomineralization are often composed of simple repeats of peptide sequences; however, the relationship between these repetitive structures and their functions remains largely unknown. Here we show that an artificial protein containing a repeated peptide sequence allows NaCl, KCl, CuSO(4) and sucrose to form a variety of macroscopic structures, as represented by their dendritic configurations. Mutational analyses revealed that the physicochemical characteristics of the protein, not the peptide sequence per se, were responsible for formation of the dendritic structures. This suggests that proteins that modulate crystal growth may have evolved as repeat-containing forms at a relatively high rate. These observations could serve as the basis for developing new genetic programming systems for creation of artificial proteins able to modulate crystal growth from inorganic compounds, and may thus provide a new tool for nano-biotechnology.

Crystallization↗
PubMed2003

Characterization of folding pathways of the type-1 and type-2 periplasmic binding proteins MglB and ArgT.

The family of periplasmic binding proteins (PBPs) is believed to have arisen from a common ancestor and to have differentiated into two types. At first approximation, both types of PBPs have the same fold pattern, reflecting their common origin. However, the connection between the main chains of a type 2 PBP is more complicated than a type 1 PBP's. We have been interested in the possibility that such structural changes affect the folding of PBPs. In this study, we have characterized the folding pathways of MglB (a type 1 PBP) and ArgT (a type 2 PBP) by using urea gradient gel electrophoresis, fast protein size-exclusion liquid chromatography and hydrophobic dye ANS binding assay. We found a distinct difference in folding between these two proteins. The folding of MglB followed a simple two-state transition model, whereas the folding of ArgT was more complicated.

Biological Transport, Active↗
PubMed2003

Translated products of tandem microgene repeats exhibit diverse properties also seen in natural proteins.

Repetitiousness is often observed in the primary and tertiary structures of proteins. We are intrigued by the potential role played by periodicity in the evolution of proteins and have created artificial repetitious proteins from repeats of short DNA sequences (microgenes). In this paper we characterize the physicochemical properties of six such artificially created proteins, which are the translated products of repeats of three microgenes. Three of the six proteins contain beta-sheet-like structures and are rather hydrophobic in nature. These proteins form macroscopic membranous structures in the presence of monovalent cationic ions, suggesting they have the capacity to promote strong intermolecular interactions. Of the other three proteins, one is comprised of alpha-helices and two have disordered structures. Small angle X-ray scattering analysis indicates that the artificial proteins do not fold as tightly as natural proteins, but are more compact than if completely denatured. One alpha-helical protein whose microgene unit was designed from coiled coil proteins was crystallized, demonstrating that repetitious artificial proteins can undergo transition to a more ordered state under appropriate conditions. Application of this approach to the development of a novel protein engineering system is discussed.

Amino Acid Sequence↗