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T Yokoi

Publications and source records attributed to T Yokoi.

At least 271 records · Page 15Linked to original sources
PubMed1987

Molecular markers for the agouti coat color locus of the mouse.

The agouti (a) coat color locus of the mouse acts within the microenvironment of the hair follicle to control the relative amount and distribution of yellow and black pigment in the coat hairs. Over 18 different mutations with complex dominance relationships have been described at this locus. The lethal yellow (Ay) mutation is the top dominant of this series and is uniquely associated with an endogenous provirus, Emv-15, in three highly inbred strains. However, we report here that it is unlikely that the provirus itself causes the Ay-associated alteration in coat color, since one strain of mice (YBR-Ay/a) lacks the provirus but still retains a yellow coat color. Using single-copy mouse DNA sequences from the regions flanking Emv-15 we have detected three patterns of restriction fragment length polymorphisms (RFLPs) within this region that can be used as molecular markers for different agouti locus alleles: a wild-type agouti (A) pattern, a pattern which generally cosegregates with the nonagouti (a) mutation, and a pattern which is specific to Emv-15. We have used these RFLPs and a panel of 28 recombinant inbred mouse strains to determine the genetic linkage of these sequences with the agouti locus and have found complete concordance between the two (95% confidence limit of 0.00 to 3.79 centimorgans). We have also physically mapped these sequences by in situ hybridization to band H1 of chromosome 2, thus directly confirming previous assignments of the location of the agouti locus.

Alleles↗
PubMed1987

The GCR1 gene encodes a positive transcriptional regulator of the enolase and glyceraldehyde-3-phosphate dehydrogenase gene families in Saccharomyces cerevisiae.

The intracellular concentrations of the polypeptides encoded by the two enolase (ENO1 and ENO2) and three glyceraldehyde-3-phosphate dehydrogenase (TDH1, TDH2, and TDH3) genes were coordinately reduced more than 20-fold in a Saccharomyces cerevisiae strain carrying the gcr1-1 mutation. The steady-state concentration of glyceraldehyde-3-phosphate dehydrogenase mRNA was shown to be approximately 50-fold reduced in the mutant strain. Overexpression of enolase and glyceraldehyde-3-phosphate dehydrogenase in strains carrying multiple copies of either ENO1 or TDH3 was reduced more than 50-fold in strains carrying the gcr1-1 mutation. These results demonstrated that the GCR1 gene encodes a trans-acting factor which is required for efficient and coordinate expression of these glycolytic gene families. The GCR1 gene and the gcr1-1 mutant allele were cloned and sequenced. GCR1 encodes a predicted 844-amino-acid polypeptide; the gcr1-1 allele contains a 1-base-pair insertion mutation at codon 304. A null mutant carrying a deletion of 90% of the GCR1 coding sequence and a URA3 gene insertion was constructed by gene replacement. The phenotype of a strain carrying this null mutation was identical to that of the gcr1-1 mutant strain.

Base Sequence↗
PubMed1987

Transcription of the constitutively expressed yeast enolase gene ENO1 is mediated by positive and negative cis-acting regulatory sequences.

There are two enolase genes, ENO1 and ENO2, per haploid yeast genome. Expression of the ENO1 gene is quantitatively similar in cells grown on glucose or gluconeogenic carbon sources. In contrast, ENO2 expression is induced more than 20-fold in cells grown on glucose as the carbon source. cis-Acting regulatory sequences were mapped within the 5'-flanking region of the constitutively expressed yeast enolase gene ENO1. A complex positive regulatory region was located 445 base pairs (bp) upstream from the transcriptional initiation site which was required for ENO1 expression in cells grown on glycolytic or gluconeogenic carbon sources. A negative regulatory region was located 160 bp upstream from the transcriptional initiation site. Sequences required for the function of this negative regulatory element were mapped to a 38-bp region. Deletion of all or a portion of these latter sequences permitted glucose-dependent induction of ENO1 expression that was quantitatively similar to that of the glucose-inducible ENO2 gene. The negative regulatory element therefore prevents glucose-dependent induction of the ENO1 gene. Hybrid 5'-flanking regions were constructed which contained the upstream regulatory sequences of one enolase gene fused at a site upstream from the TATAAA box in the other enolase gene. Analysis of the expression of enolase genes containing these hybrid 5'-flanking region showed that the positive regulatory regions of ENO1 and ENO2 were functionally similar, as were the regions extending from the TATAAA boxes to the initiation codons. Based on these studies, we conclude that the negative regulatory element plays the critical role in maintaining the constitutive expression of the ENO1 structural gene in cells grown on glucose or gluconeogenic carbon sources.

Amino Acid Sequence↗
PubMed1987

Localization of the functional sites on the alpha chain of acetylcholine receptor.

A comprehensive synthetic approach, previously developed in this laboratory, has been applied to systematically screen the entire extracellular part (residues 1-210) of the alpha chain of the Torpedo californica acetylcholine receptor (AChR) for the profiles of the continuous regions that are recognized by antibodies against free, or membrane-sequestered, AChR; the regions recognized by AChR-primed T cells; the regions that bind alpha-bungarotoxin and cobratoxin; and an acetylcholine-binding region. Eight continuous antigenic sites were localized in this part of the alpha chain by all of the antisera tested. The sites were independent of the host species from which the antisera were obtained and were also similar to antisera against the isolated pentameric AChR or against the membrane-sequestered AChR. Six regions were found to stimulate AChR-primed T cells (T sites). Three of the T sites coincided with regions recognized by antibodies. At least two T sites had no detectable antibody responses directed to them. Five toxin-binding regions were localized, and may constitute distinct sites or, alternatively, different faces in one (or more) sites. Some of these regions coincided with regions recognized by anti-AChR antibodies. One of the toxin-binding regions bound acetylcholine, and immunization with this peptide induced experimental autoimmune myasthenia gravis.

Acetylcholine↗
PubMed1986

Biochemical and immunological characterization of Suncus murinus mammary tumor virus DNA polymerase.

Enzymological properties of the RNA-directed DNA polymerase associated with the Suncus murinus mammary tumor virus (Sm-MTV) was investigated and its antigenic relatedness to other retroviral DNA polymerases was examined. The enzyme exhibited higher activity in the presence of Mg2+ than in the presence of Mn2+ with endogenous RNA as well as with almost all of the synthetic template X primers tested. Mg2+ was also effective with poly(2'-O-methylcytidylate) X oligodeoxyguanylate which was known to be specific for Mn2+. To examine the immunological relatedness of this enzyme with other retroviral DNA polymerases, remaining Sm-MTV DNA polymerase activity was measured after treatment of this enzyme with various antisera prepared against each of the reverse transcriptases of Mason-Pfizer monkey virus (MPMV), murine mammary tumor virus (MuMTV), simian sarcoma virus-simian sarcoma associated virus (SSV/SSAV), and Rauscher murine leukemia virus (RLV). No inhibition of the Sm-MTV enzyme activity was observed when treated with the latter three antisera with which the DNA polymerase activities of the corresponding retroviruses were fully inhibited. Only the antiserum against MPMV-enzyme, however, was found to slightly inhibit the Sm-MTV enzyme activity. These results indicate that Sm-MTV DNA polymerase has similar enzymological properties to those of MPMV and MuMTV and shares some common antigenic determinant group(s) with MPMV DNA polymerase.

Animals↗
PubMed1986

Isolation of transcribed DNA sequences from chromosome 21 using mouse fetal cDNA.

A technique for isolating DNA sequences that are likely to be transcriptionally active in both humans and mice has been developed. This method is based on the screening of a human genomic DNA library with single stranded cDNA prepared from late gestation mouse fetal RNA. Using a human chromosome 21 DNA library, we have isolated and characterized two clones which are entirely composed of single copy human DNA sequences and are 2.7 and 6.7 kilobases in length. The 2.7 kilobase clone is homologous to a transcript found predominantly in nonpolyadenylated human fibroblast RNA. It also shows homology to mouse genomic DNA and recognises several polyadenylated RNAs in mouse testis. This cloned sequence has been mapped by in situ hybridization to the distal third of chromosome 21, the region involved in the causation of Down syndrome.

Animals↗
PubMed1986

Class distribution of immunoglobulin-containing plasma cells in the stroma of medullary carcinoma of breast.

A class distribution of plasma cells associated with the stroma in twenty-eight cases of medullary carcinoma of the breast was investigated by an unlabeled immunoperoxidase method. The stroma of the medullary carcinomas tested was found to contain predominantly IgG plasma cells except in two cases. Stroma of the other types of breast carcinoma, including ten cases of papillo-tubular carcinoma, five cases of scirrhous carcinoma, and six cases of medullary tubular carcinoma, contained predominantly IgG plasma cells, although few plasma cells were associated with carcinoma tissues in the latter group. Plasma cells associated with control specimens, including normal breast, fibroadenoma, cystic disease, and intraductal papilloma, were found to be predominantly of IgA type. Few carcinomatous epithelial cells contained secretory components in the cytoplasm, while a number of cells positive for secretory components were observed in acinar and ductular epithelia of normal breast tissues and in benign proliferative lesions of the breast. It is suggested that the lymphoid cells infiltrating the stroma of medullary carcinoma represent a sign of host immune response against the carcinoma cells which is related to the well-known favorable prognosis associated with this tumor.

Adenocarcinoma↗
PubMed1986

Identification of a regulatory region that mediates glucose-dependent induction of the Saccharomyces cerevisiae enolase gene ENO2.

There are two yeast enolase genes, designated ENO1 and ENO2, which are expressed differentially in vegetative cells grown on glucose and in cells grown on gluconeogenic carbon sources. ENO2 is induced more than 20-fold in cells grown on glucose, whereas ENO1 expression is similar in cells grown on glucose and in cells grown on gluconeogenic carbon sources. Sequences within the 5' flanking region of ENO2 which are required for glucose-dependent induction were identified by deletion mapping analysis. These studies were carried out by using a fused gene containing the ENO2 5' flanking sequences and the ENO1 coding sequences. This fused gene undergoes glucose-dependent induction and is expressed at the same level as the resident ENO2 gene in cells grown on glucose or gluconeogenic carbon sources. Expression of fused genes containing deletion mutations within the ENO2 5' flanking region was monitored after integration at the ENO1 locus of a strain carrying a deletion of the resident ENO1 coding sequences. This analysis showed that there are two upstream activation sites located immediately upstream and downstream from a position 461 base pairs upstream from the transcriptional initiation site. Either one of these upstream activation sites is sufficient for glucose-dependent induction and normal gene expression in the presence of gluconeogenic carbon sources. Deletion of both regulatory regions results in a complete loss of gene expression. The regulatory regions function normally in both orientations relative to the coding sequences. Mutant fused genes containing small deletions within the regulatory regions were constructed; these genes were expressed normally in gluconeogenic carbon sources but were not induced in the presence of glucose. Based on this analysis, ENO2 contains a cis-acting regulatory region which is required for gene expression and mediates glucose-dependent induction of gene expression.

Base Sequence↗
PubMed1986

Ultrastructural characterization of the retrovirus particles (Sm-MTV) liberated from the mammary tumor cell line (Sm-MT) of a house musk shrew, Suncus murinus (Insectivora).

Detailed ultrastructure of a new type of retrovirus (Sm-MTV) released by cultured cells (Sm-MT) of a spontaneous mammary tumor from a house musk shrew Suncus murinus, Insectivora, is described. The virus particles were revealed as three forms: intracellular; budding; and extracellular. The intracellular type A particles were similar in profile to those associated with mouse mammary tumor cells and tended to form a small cluster of several particles in the cytoplasm. In addition, horseshoe-shaped particles as well as smaller particles in clusters, with doughnut-shaped morphology similar in structure to type A particles, were identified near the clusters of type A particles, although in smaller numbers. The budding particles contained a doughnut-shaped nucleoid, although the nucleoids decreased in size as compared with intracytoplasmic type A particles. The extracellular virions consisted of an envelope and a centrally located nucleoid. In routinely fixed specimens, the former was covered with irregularly distributed fuzzy materials in its surface, and the latter was further composed of a small electron dense core surrounded by an intermediate layer. Tannic acid treatment of cells resulted in the visualization of surface projections on the envelope of virions. Similar projections were also detected exclusively on the plasma membrane where virus budding took place, and not on the normal plasma membrane. The presence of surface projections on the viral envelope was further confirmed by the whole-cell-mounting technique. Together with our previous results of biochemical and immunological investigations, we concluded that Sm-MTV seemed to have closer phylogenetic relatedness with type D viruses of primates than with murine mammary tumor virus.

Animals↗
PubMed1986

[An autopsy case of adult neuroblastoma].

The patient was a 31-year-old man with neuroblastoma of the right adrenal gland, which presented at first as metastatic spinal epidural tumor. Catecholamine and its products in the blood and urine and neuron-specific enolase in the blood were increased. Six months after right adrenectomy followed by chemotherapy, the patient died due to cachexia. Autopsy revealed widespread metastasis. By electron microscopy, the centers of the Homer-Wright rosettes were occupied by neuropil-like structures consisting of a number of cytoplasmic processes of tumor cells, but no cored vesicles were found either in the processes or perikaryons of the tumor cells.

Adrenal Gland Neoplasms↗
PubMed1985

A new retrovirus produced by tissue culture cell line from mammary tumor of a house musk shrew, Suncus murinus.

A new type of retrovirus (Sm-MTV) released by cultured cells of a spontaneous mammary tumor from a house musk shrew, Suncus murinus, is described. The Sm-MTV is distinct morphologically from type C particles. In spite of certain morphological similarities to type B and type D retroviruses, the Sm-MTV is readily distinguishable. The extracellular virions had a spikeless envelope containing a centrally located nucleoid with a small electron-dense core surrounded by an inner membrane. The budding particles contained a doughnut-shaped nucleoid. Intracytoplasmic type A particles similar in profile to those associated with mouse mammary tumor cells were also found, and tended to form a small cluster of several particles in the cytoplasm. The virus banded at 1.169 g/cm3 in isopycnic centrifugation and possessed constitutive Mg2+-dependent reverse transcriptase. The viral RNA had a molecular size ranging from 50 to 70 S in its native form and 30 to 40 S in its denatured form by a glycerol gradient ultracentrifugation. Major viral polypeptides were 72K, 69K, 47K, 44K/43K, 27K, 20.5K, and 15K.

Animals↗
PubMed1985

A new individual variation of saliva detected with rabbit anti-human saliva serum.

A rabbit anti-saliva hyperimmune serum was raised against pooled human saliva. After absorption with human serum and semen, the immune serum formed two or three distinct precipitation lines with human saliva by the Ouchterlony method. Based on the presence or absence of a precipitation line, close to the antigen well designated as Pl, all human saliva were divided into two groups; Pl+ and Pl-. The incidence of Pl+ saliva was 114 out of 154 samples (74%). By immunoelectrophoresis with anti-saliva serum preabsorbed with Pl- saliva, Pl+ saliva formed a precipitation line in cathodal area. No amylase activity was found in this precipitation line but it was stained with the Schiff's reagent. Pl protein was isolated by Sephadex G-100 and ion-exchange chromatography. Isoelectric focusing of the Pl protein in polyacrylamide slab gel containing urea revealed that the protein differed from any known parotid salivary proteins such as Pr, Db, Pa and Pm.

Animals↗
PubMed1985

Semiquantitation of ABH antigens specific for red blood cells.

H and A antigens expressed only in the RBC were quantitated using specific antisera, and the amount of the antigens was compared with that of total H and A antigens shared by the RBC and saliva. Total H antigen decreased in the order of O, A, B and AB blood groups. However, H antigen specific for the RBC distributed similarly among four blood groups. In addition, the amount of total A antigen in A group was more than that of AB group, but the difference in the amount of A antigen specific for the RBC was not significant between the two blood groups. B antigen specific for the RBC was not examined because of failure in preparing specific anti-B serum. In conclusion, the quantitative difference of the total H or A between A and AB groups might be due to the difference in the amount of antigen common to the RBC and saliva but not one specific for the RBC.

ABO Blood-Group System↗
PubMed1984

Serological distinction of A antigen between red blood cells and saliva in blood grouping of blood and body fluid stains.

A antigens of red blood cells and body fluids such as saliva, semen and sweat could be serologically distinguished using rabbit or guinea pig immune anti-A. As for antisera specific for red blood cell A, A+ rabbits were intravenously immunized with A group red blood cells. The resulting antisera were absorbed with O and B red cells and with A. Se saliva. The absorbed anti-A reacted with A red cells (titer 1:32) and was not inhibited with A. Se saliva. Guinea pigs were intramuscularly injected with A. Se saliva. Crude antisera contained agglutinins to human red cells which were abolished by absorption with A red cells. After absorption with O. Se saliva, the antisera were proved to have agglutinin activity with A group saliva using latex coated with A. Se saliva. A antigens from blood or body fluid stains could be distinguished by the elution method with these anti-A sera.

ABO Blood-Group System↗