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Biomedical subjects

S Sugano

Publications and source records attributed to S Sugano.

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

cDNA cloning, tissue expression, and chromosomal assignment of a mouse gene, encoding a 127 kDa UV-damaged DNA binding protein which is defective in XPE cells.

A subset of xeroderma pigmentosum (XP) group E cells lack a factor of the UV-damaged DNA binding activity. Both 127 kDa and 48 kDa proteins have been reported to be responsible for the binding activity. A cDNA for the 127 kDa UV-damaged DNA-binding protein (p127-Ddb1) was isolated from a mouse fetal brain full length-enriched cDNA library, and an open reading frame of 1140 amino acids was identified. Reverse transcription-coupled polymerase chain reaction (RT-PCR) showed that mouse Ddb1 messenger is ubiquitously expressed in adult tissues as well as in embryo's. The gene was mapped to near the public locus D19Mit22 region of mouse chromosome 19.

Amino Acid Sequence↗
PubMed1999

The protein kinase CK2 is involved in regulation of circadian rhythms in Arabidopsis.

A wide range of processes in plants, including expression of certain genes, is regulated by endogenous circadian rhythms. The circadian clock-associated 1 (CCA1) and the late elongated hypocotyl (LHY) proteins have been shown to be closely associated with clock function in Arabidopsis thaliana. The protein kinase CK2 can interact with and phosphorylate CCA1, but its role in the regulation of the circadian clock remains unknown. Here we show that plants overexpressing CKB3, a regulatory subunit of CK2, display increased CK2 activity and shorter periods of rhythmic expression of CCA1 and LHY. CK2 is also able to interact with and phosphorylate LHY in vitro. Additionally, overexpression of CKB3 shortened the periods of four known circadian clock-controlled genes with different phase angles, demonstrating that many clock outputs are affected. This overexpression also reduced phytochrome induction of an Lhcb gene. Finally, we found that the photoperiodic flowering response, which is influenced by circadian rhythms, was diminished in the transgenic lines, and that the plants flowered earlier on both long-day and short-day photoperiods. These data demonstrate that CK2 is involved in regulation of the circadian clock in Arabidopsis.

Amino Acid Sequence↗
PubMed1999

BH-protocadherin-c, a member of the cadherin superfamily, interacts with protein phosphatase 1 alpha through its intracellular domain.

Using a yeast two-hybrid system, we isolated eight cDNA clones which interacted with BH-protocadherin-c (BH-Pcdh-c) from the human brain cDNA library. One clone encoded protein phosphatase type I isoform alpha (PP1alpha) and another two PP1alpha2. PP1alpha was co-immunoprecipitated from the extract of a gastric adenocarcinoma cell line MKN-28 with anti-BH-Pcdh-c antibody. PP1alpha activity towards glycogen phosphorylase was inhibited by the intracellular domain of BH-Pcdh-c. Inhibition of the phosphatase required more than the minimal domain of BH-Pcdh-c which could associate with PP1alpha. In situ hybridization revealed that BH-Pcdh-c mRNA was predominantly expressed in cerebral cortex neurons in the adult mouse brain.

Animals↗
PubMed1999

Molecular cloning and characterization of a novel cbl-family gene, cbl-c.

We have cloned a novel gene, cbl-c, of mammalian cbl-family. The cbl-c gene is predicted to encode a protein of 52 kDa that has a phosphotyrosine-binding domain, a RING finger and a proline-rich region. Cbl-c shows 50% homology to the amino-terminal sequences of Cbl and Cbl-b, but a sequence corresponding to the carboxy-terminal half of Cbl and Cbl-b is largely missing in Cbl-c. The expression of cbl-c mRNA is distinct from that of cbl and cbl-b mRNAs, being high in the colon and small intestine, but undetectable in brain and lymphoid tissues. The cbl-c gene is mapped in 19q13.2-13.3. Finally, the 52 kDa Cbl-c protein binds to the EGF receptor and Fyn tyrosine kinase. We conclude that Cbl-c is a novel Cbl-family adaptor protein that would regulate intracellular signaling mediated by various tyrosine kinases.

Amino Acid Sequence↗
PubMed1999

The promoter region of human prepro-nociceptin gene and its regulation by cyclic AMP and steroid hormones.

The promoter and upstream regulatory region of the human prepro-nociceptin gene has been cloned from adaptor-ligated genomic DNA libraries by polymerase chain reaction. This 1.7 kb region contains several potential binding sites for transcription factors, among which are binding sites for TF-IID, cyclic AMP response element binding protein, glucocorticoid receptor and estrogen receptor. Multiple start points for the transcription of prepro-nociceptin are identified by an 'oligoribonucleotide-capping' method, but the major one is located at -558(G). Promoter activity assays using luciferase reporter gene constructions with the 1.7 kb fragment and a series of deletion mutations demonstrate that the core promoter is located in the region from -639 to -521 (a region surrounding the major transcription start point -558). A TATA-box motif displays weak promoter activity. An increase of cellular cyclic AMP levels by forskolin treatment up-regulates prepro-nociceptin transcription. Estrogen also up-regulates gene transcription whereas glucocorticoid down-regulates transcription, each through their corresponding receptor response elements. These regulatory effects can be blocked either by mutations of the potential cyclic AMP- or estrogen receptor response elements or by the application of antagonists for glucocorticoid and estrogen receptors. These findings provide a molecular basis for the regulatory mechanisms of human prepro-nociceptin gene expression.

Base Sequence↗
PubMed1999

A 189-bp repeat region within the human cytomegalovirus replication origin contains a sequence dispensable but irreplaceable with other sequences.

The human cytomegalovirus (HCMV) replication origin exhibits a strain-dependent difference in the number of copies of a 189-bp region: the AD169 and Towne strains contain one and three copies of the region, respectively. A nearly complete deletion of the 189-bp repeat region of the Towne strain does not eliminate the origin's ability to initiate DNA synthesis. Here we report that the replication ability of the HCMV replication origin in infected cells disappeared after replacements of an internal sequence (152 bp) of the 189-bp repeat region with lambda DNA of identical and different lengths as well as after introduction of multiple nucleotide substitutions within the 152-bp internal sequence of the 189-bp repeat. In contrast, a variation in the copy number of 189-bp region (either one or two copies) or an inversion of the 152-bp internal sequence of the 189-bp repeat maintained replication abilities similar to those of the wild-type origin of the Towne strain. These results indicate that the 189-bp repeat region within the HCMV replication origin is not just a dispensable spacer sequence but instead contains an irreplaceable sequence that may play a supporting role in HCMV DNA replication.

Amino Acid Substitution↗
PubMed1999

A core promoter and a frequent single-nucleotide polymorphism of the mismatch repair gene hMLH1.

The hMLH1 gene encodes a protein that is involved in the DNA mismatch repair system. The coding region of the hMLH1 gene has been known to be mutated in a subset of patients with hereditary nonpolyposis colorectal cancer (HNPCC). Our current research characterized the promoter region of the hMLH1 gene and searched for mutations correlating to HNPCC. Utilizing the oligo-capping method, major transcription start sites of the hMLH1 gene were mapped at two locations. The core promoter region of about 180 bp was determined by the luciferase assay of serial deletion mutants. Although we did not find any pathogenic mutation in the hMLH1 promoter region by PCR-SSCP, we found a single-nucleotide polymorphism at position -93 nt from the adenine residue of the start codon. By PCR-RFLP analysis with Pvu II for this polymorphism, we detected LOH in four tumors from three patients. An easy detection of this polymorphism with PCR-RFLP and high incidence ( approximately 50%) of informative cases make this polymorphism a suitable marker for the detection of hMLH1 allelic losses.

3T3 Cells↗
PubMed1999

Two short sequences have positive effects on the human p27Kip1 gene transcription.

The cyclin-dependent kinase (Cdk) inhibitor p27Kip1 plays an important role in the progression from G1 to S phase in the cell cycle. To study the activities of its promoter and other regulatory elements, we have cloned and characterized the 5'-flanking region of the human p27Kip1 gene. This region, about 3kb in length, is GC-rich and shares homology with that of the mouse p27Kip1 gene. Transcription start points (tsp) determined by the oligo-capping method are mapped in two regions, the cluster I (-479 to -403) and cluster II (-280 to -273). The cluster I was the primary functional site in transcription initiation. The luciferase activities of serial deletion mutants indicated that two short sequences (-581 to -557 and -556 to -526) had positive effects on transcription. The gel shift assay showed that factors in HeLa nuclear extract bound to these sequences. Sp1 was the major binding factor to the sequence of -556 to -526, wheres yet unidentified positive factors bound to the sequence of -581 to -557.

Base Sequence↗
PubMed1999

Chemokine PARC gene (SCYA18) generated by fusion of two MIP-1alpha/LD78alpha-like genes.

Two loci in the human genome, chromosomes 4q12-q21 and 17q11.2, contain clusters of CXC and CC chemokine subfamily genes, respectively. Since mice appear to contain fewer chemokine genes than humans, numerous gene duplications might have occurred in each locus of the human genome. Here we describe the genomic organization of the human pulmonary and activation-regulated CC chemokine (PARC), also known as DC-CK1 and AMAC-1. Despite high sequence similarity to a CC chemokine macrophage inflammatory protein-1alpha (MIP-1alpha)/LD78alpha, PARC is chemotactic for lymphocytes and not for monocytes and does not share its receptor with MIP-1alpha. Analyses of the BAC clones containing the human PARC gene indicated that the gene is located most closely to MIP-1alpha (HGMW-approved symbol SCYA3) and MIP-1beta (HGMW-approved symbol SCYA4) on chromosome 17q11.2. Dot-plot comparison suggested that the PARC gene had been generated by fusion of two MIP-1alpha-like genes with deletion and selective usage of exons. Base changes accumulated before and after the fusion might have adapted the gene to a new function. Since there are variably duplicated copies of the MIP-1alpha gene called LD78beta (HGMW-approved symbol SCYA3L) in the vicinity of the MIP-1alpha gene, the locus surrounding the MIP-1alpha gene seems to be a "hot spring" that continuously produces new family genes. This evidence provides a new model, duplication and fusion, of the molecular basis for diversity within a gene family.

Animals↗
PubMed1999

Azygos venous blood flow while fasting, postprandially, and after endoscopic variceal ligation, measured by magnetic resonance imaging.

Using cine phase-contrast magnetic resonance (MR) imaging, we measured fasting and postprandial azygos blood flow in 15 cirrhotic patients with portal hypertension and 11 healthy controls. In 10 of the cirrhotics, measurements were made before and after prophylactic endoscopic variceal ligation therapy (EVL). Flow volume was measured in the azygos vein at the level of the midthoracic vertebra. Azygos blood flow was measured under basal fasting conditions and 30-40 min after ingestion of a 500 Kcal meal. Fasting azygos blood flow was 139 +/- 43 ml/min in controls vs 519 +/- 249 ml/min in cirrhotics (P < 0.01). Eating significantly increased azygos blood flow, by 38% in controls (P < 0.02) and by 27% in cirrhotics (P < 0.02), compared with fasting conditions. EVL markedly decreased azygos blood flow, by 25% compared with pre-EVL (P < 0.03). The cine phase-contrast MR velocity mapping method measured flow volume in the azygos veins. Azygos blood flow was markedly greater in the cirrhotics than in the controls. In the cirrhotics and controls, blood flow volume increased after eating. Azygos blood flow was significantly reduced by successful EVL.

Adult↗
PubMed1999

Portal venous blood flow while breath-holding after inspiration or expiration and during normal respiration in controls and cirrhotics.

In this study, we used magnetic resonance (MR) imaging to measure portal blood flow in 12 healthy controls and 17 cirrhotics while they were breath-holding after inspiration and after expiration. We then compared the results with measurements made during normal respiration in the healthy controls and cirrhotics. Blood flow in the main portal vein under basal fasting conditions was quantitated using the cine phase-contrast MR velocity mapping method. Three measurements were made on one occasion, as follows: (1) throughout the cardiac cycle during normal respiration, (2) with the subject breath-holding after maximal inspiration, and (3) with the subject breath-holding after maximal expiration. During normal respiration, portal blood flow was 1.3 +/- 0.21/min in controls vs 1.0 +/- 0.11/min in cirrhotics (P < 0.0001); while subjects were breath-holding after inspiration, portal blood flow was 1.0 +/- 0.21/min in controls vs 0.9 +/- 0.11/min in cirrhotics; and while subjects were breath-holding after expiration, portal blood flow was 1.5 +/- 0.21/min in controls vs 1.1 +/- 0.21/min in cirrhotics (P < 0.0001). The differences were primarily due to changes in flow velocity. When the magnitude of these hemodynamic changes in the three respiratory conditions was compared in controls and cirrhotics, analysis of variance (ANOVA) showed a significant difference (P < 0.0001). In controls, portal blood flow decreased during maximal inspiration relative to flow during normal respiration (-24.6 +/- 8.3%). Changes in portal blood flow in controls were greater than in cirrhotics (-13.5 +/- 4.5%) (P < 0.0001); however, the difference in blood flow increase associated with maximal expiration between the two groups (+11.8 +/- 9.4% vs +5.9 +/- 11.5%) was not significant. We found that the respiration-induced hemodynamic variation in portal blood flow was less in cirrhotics than in the healthy controls. Portal blood flow measurements made during normal respiration using MR imaging closely reflect nearly physiologic conditions.

Adult↗
PubMed1999

A novel human gene whose product shares significant homology with the bovine brain-specific protein p25 on chromosome 5p15.3.

Here, we report on the sequence features and chromosomal location of a novel human gene which shares significant homology with the bovine brain-specific protein p25. Based on polymerase chain reaction analysis with a human/rodent monochromosomal hybrid cell panel and a radiation hybrid panel, the gene was mapped on to p15.3 region of chromosome 5.

Amino Acid Sequence↗
PubMed1999

Isolation and chromosomal mapping of a novel human gene showing homology to Na+/PO4 cotransporter.

We isolated a cDNA clone which shows a significant similarity with the renal Na+/phosphate cotransporter (NPT) from a human intestine mucosa cDNA library. The cDNA is 2626 bases long, with one open reading frame encoding a protein of 497 amino acids. The deduced amino acids sequence shows an overall homology of 48% with the human renal NPT1 protein. This gene is expressed in intestine, colon, liver, and pancreas. Thus, this gene may code for intestinal type NPT or closely related proteins. The chromosomal location of the gene was determined on the chromosome 6p21.3-p22 region by polymerase chain reaction-based analysis with both a human/rodent mono-chromosomal hybrid cell panel and a radiation hybrid mapping panel.

Amino Acid Sequence↗
PubMed1999

Cloning, expression analysis, and chromosomal localization of a novel butyrophilin-like receptor.

We isolated a cDNA clone which shows a similarity with human butyrophilin from a human colon mucosa cDNA library. The cDNA is 1964 bases long, with one open reading frame encoding a protein of 433 amino acids. The deduced amino acid sequence shows an overall homology of 36.5% with the human butyrophilin protein. This gene is mainly expressed in small intestine, colon, testis, and leukocytes. The chromosomal location of the gene was determined on the chromosome 5q35 region by polymerase chain reaction-based analysis with both a human/rodent monochromosomal hybrid cell panel and a radiation hybrid mapping panel.

Amino Acid Sequence↗
PubMed1999

Induction of c-met proto-oncogene expression at the metastatic site.

In metastatic processes, gene expression may variously alter through interactions between tumor and host stromal cells at the metastatic site. Using a tail vein injection-lung metastatic model and differential display, we analyzed alteration of gene expression in experimentally metastasized lesions. We found that expression of the c-met proto-oncogene was elevated in the lungs metastasized by MC-1 cells. The up-regulation of c-met was also observed in the lungs metastasized by B16 melanoma cells. In situ hybridization analysis revealed that the elevation of c-met expression apparently occurred in tumor cells but did not in lung stromal cells at the metastatic site. The c-Met protein was also highly expressed and phosphorylated. The upregulation of c-met appeared to be caused by induction of gene expression but not to be due to preferential selection of tumor cells highly expressing c-met. These findings suggest that the c-met proto-oncogene is up-regulated at the transcription level through some interactions between tumor and host stromal cells.

Animals↗
PubMed1999

Relationship of portal pressure and colorectal vasculopathy in patients with cirrhosis.

We studied the relationship between portal pressure and colorectal mucosal vascular lesions in cirrhotics and the effectiveness of drug therapy in treating these lesions. Colonoscopy and hepatic venous pressure gradient (HVPG) studies were performed in 21 cirrhotics. Oral spironolactone plus transdermal nitroglycerin were given to patients who had diffuse mucosal cherry-red spots and/or rectal varices. The colonoscopy and HVPG determinations were repeated after four weeks. Colonoscopic findings included vascular ectasias in 13 patients (62%), diffuse cherry-red spots in the rectum in five patients (24%), and rectal varices in eight patients (38%). Overall, colorectal mucosal vascular lesions were found in 16 cirrhotics (76%). These findings were not found in 21 age- and sex-matched noncirrhotic controls. Vascular ectasias appeared without relationship to the HVPG. Patients with diffuse cherry-red spots (N = 5, 22.4+/-3.4 mm Hg) had a significantly higher HVPG than those without (N = 16, 16.6+/-3.3 mm Hg, P < 0.01). However, no significant difference was found in HVPG between patients with rectal varices (N = 8, 19.4+/-4.6 mm Hg) and patients without rectal varices (N = 13, 17.2+/-3.8 mm Hg). After four weeks of drug therapy, diffuse cherry-red spots became less obvious when the HVPG decreased more than 20%. Rectal varices did not change their appearance with HVPG reduction. We found that colorectal vascular lesions are common in cirrhotics. Diffuse cherry-red spots are probably dependent on elevated portal pressure, but vascular ectasias and rectal varices are not related to the degree of portal pressure. Chronic drug therapy with reduction of portal pressure improves colonoscopic findings such as diffuse cherry-red spots.

Administration, Cutaneous↗
PubMed1999

The developmental fate of green fluorescent mouse embryonic germ cells in chimeric embryos.

Primordial germ cells (PGCs), as precursors of mammalian germ lineage, have been gaining more attention as a new resource of pluripotent stem cells, which bring a great possibility to study developmental events of germ cell in vitro and at animal level. EG4 cells derived from 10.5 days post coitum (dpc) PGCs of 129/svJ strain mouse were established and maintained in an undifferentiated state. With an attempt to study the differentiation capability of EG4 cells with a reporter protein: green fluorescence protein, and the possible application of EG4 cells in the research of germ cell development, we have generated several EG4-GFP cell lines expressing enhanced green fluorescence protein (EGFP) and still maintaining typical characteristics of pluripotent stem cells. Then, the differentiation of EG4-GFP cells in vitro as well as their developmental fate in chimeric embryos which were produced by aggregating EG4-GFP cells to 8-cell stage embryos were studied. The results showed that EG4 cells carrying green fluorescence have a potential use in the research of germ cell development and other related studies.

Animals↗