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Volume 6 (1981)
- Issue 4 Pages 301-
- Issue 3 Pages 201-
- Issue 2 Pages 93-
- Issue 1 Pages 1-
Volume 6, Issue 2
Displaying 1-10 of 10 articles from this issue
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Kiyoshi Nose, Hiroshi Okamoto, Masayoshi Namba1981 Volume 6 Issue 2 Pages 93-101
Published: 1981
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe sequence homologies of poly(A)-containing RNA and protein species were analyzed with normal WI-38 and transformed WI-38 (CT-1) developed from a Co60-irradiated population in order to identify the change in gene expression in transformed cells.
Poly(A)+ RNA was extracted from normal and transformed cells ; cDNA against poly(A)+RNA was synthesized. Results of cross-hybridization between poly(A)+RNA and cDNA showed that the sequences of the poly(A)+RNA of normal and transformed cells were extensively homologous.
In contrast, when proteins dissolved from [35S]Met-labeled cells were com-pared by two-dimensional gel electrophoresis, two of them were found only in normal cells. Two other proteins were identified which were synthesized in transformed cells but were not found in normal cells (approximately 200 spots examined).
Our results indicate that transformation of human fibroblasts only is accompanied by limited alteration in genetic expression.View full abstractDownload PDF (806K) -
Hiroto Naora, Nicholas J. Deacon1981 Volume 6 Issue 2 Pages 103-110
Published: 1981
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSIn situ secondary structures of chicken reticulocyte heterogene-ous nuclear RNA (HnRNA) were investigated using a nucleic acid intercalating agent.
Double-stranded regions, if present in situ, of chicken reticulocyte HnRNA were cross-linked by treating isolated reticulocyte nuclei with the psolaren derivative, 4'-hydroxymethyl-4, 5', 8-trimethyl psoralen and ultraviolet irradi-ation. HnRNA was then isolated and examined by electron microscopy under stringent denaturation conditions. At least four different shapes of molecules were seen: a) filamentous forms without any loops or fold back structures at the ends, or b) with a small loop (or fold-back structure) at one end only and c) large or medium sized loop-bearing molecules without or d) with a small loop (or fold-back structure) at one end.
It is suggested that small and large loops found in the above shapes of molecules represent the 5'-and 3'-terminal double-stranded hairpin structures, respectively. This result implies an in situ occurrence in nuclei of the intra-molecular hairpin structure in chicken reticulocyte HnRNA molecules.
It was estimated that intervening sequences 1 and 2 of chicken β-globin 'pre-mRNA' would be 113-120 and 671-690 nucleotides long, respectively.View full abstractDownload PDF (775K) -
Sadao Gotoh, Hideyasu Hirano, Ken Higashi, Eiji Shimomura, Akira Nakan ...1981 Volume 6 Issue 2 Pages 111-119
Published: 1981
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe cyclic change of nucleolar number per nucleus in synchronized L-929 cells was observed during the traverse of cell cycles. The reduction of the nucleolar number, however, is not due to the disappearance of nucleoli during the replication of their chromatins for the following reasons : 1) The average number of nucleoli of synchronized L-cells was 1.84 for S phase and 1.46 for G2 and/or G1 phase. 2) Incorporation of [3H]thymidine into nucleolar DNA of synchronized L-cells was observed mainly in the S phase. Therefore, the lowest average number of nucleoli per nucleus was not observed in the S phase, in which the bulk of nucleolar DNA was under replication. 3) In randomly growing mouse ascites tumor cells, the specific activities of DNAs of nucleolar and extranucleolar chromatins which incorporated [3H]thymidine in vivo were similar. Therefore, the newly synthesized extranucleolar chromatin was not the precursor of nucleolar chromatin. 4) Three known DNA polymerases α, β and γ were found to be present in the extracts of isolated nucleoli from Ehrlich ascites tumor cells. So nucleoli themselves appear to have the machinery for DNA replication. These results suggest that the reproduction of nucleolar chromatins in mouse cells is not associated with disorganization of the whole nucleolar structure.View full abstractDownload PDF (1021K) -
Yasuhiko Niiyama, Reiko Sasada, Koichi Igarashi, Tsutomu Kurokawa, Yuk ...1981 Volume 6 Issue 2 Pages 121-131
Published: 1981
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSSome properties of A31 cells (a clonal line of BALB/3T3 cells) transformed by fragments of DNA of bovine adenovirus type 3 (BAV3), i.e., EcoRI D fragments (3.6 to 19.7 map units of viral genome) or HindIII J-E ligated fragments (0 to 11.9 map units) produced by restriction endonuclease digestion, were examined. These transformed cells were found to commonly contain most, if not all, of the nucleotide sequences in the region of from 3.6 to 11.9 map units of BAV3 genome, by DNA-DNA reassociation kinetics analysis. Moreover, the synthesis of virus-specific RNA was detected by DNA-RNA hybridization experiments. TrD and TrJE cells (A31 cells transformed with Eco RI D fragments and HindIII J-E ligated fragments of BAV3 DNA, respectively) as well as A31 cells transformed with whole viral DNA or BAV3, showed a rapid uptake of 2-deoxyglucose, high cell agglutinability by plant lectins and high plasminogen acivator activity, in comparison with A31 cells. All these transformed cells produced tumors when inoculated subcutaneously into adult BALB/c mice. These results indicated that all these characteristics examined are directly or indirectly controlled by the gene(s) located between the map units of 3.6 and 11.9 of the BAV3 genome.View full abstractDownload PDF (1124K) -
Yasuhiko Niiyama1981 Volume 6 Issue 2 Pages 133-146
Published: 1981
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSAt least 13 species of bovine adenovirus type 3 (BAV3)-specific early proteins were detected when two dimensional electrophoregrams of the BAV3-infected and mock-infected cells were compared. The molecular weights and isoelectric points ranged from 15, 000 to 80, 000 and from 5.35 to 6.85, respectively. Using an immunoprecipitation method, analyses of T antigens were carried out using three types of anti T sera. These antisera were prepared from tumor-bearing mice as induced by cells transformed with whole or specific fragments of BAV3 DNA containing transforming gene(s), and characterized as being BAV3-specific by immunofluorescent studies. Proteins of an apparent molecular weight of 15, 000 (15 K) and 54, 000 (54 K) were identified as common immunoprecipitates between these antisera and extracts of the cells lytically infected with BAV3. Each of these proteins was found among BAV3-specific early proteins. These results suggest that the 15 K and 54 K proteins are BAV3 tumor antigens. On the other hand, in the BAV3-transformd cells, a protein with an apparent molecular weight of 80 K, instead of 15 K or 54 K protein, was detected, using the same method. Such observations in human adeno-viruses have not been reported. The BAV3 15 K protein seems to be suitable for the study of physicochemical properties and functions of T antigen since it can be obtained in large amounts.View full abstractDownload PDF (11075K) -
Hiroshi Sakagami, Senwa Unten, Kunio Konno1981 Volume 6 Issue 2 Pages 147-157
Published: 1981
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSMouse myeloid leukemia cells (M1) were induced to different-iate in vitro by treatment with dexamethasone. The incorporation of [3H] thymidine into acid-insoluble materials began to decline after 10 h treatment. This reflected the differentiation-associated decline of DNA synthesis activity, since (i) the thymidine was almost exclusively incorporated into nuclear DNA, (ii) the incorporation was completely blocked by arabinofuranosylcytosine and (iii) the differentiation-associated changes of intracellular pool size and specific activity of thymidine were negligible. Cell fractionation by discontinuous Ficoll-Urografin density gradients revealed that the DNA synthesis of the differentiat-ed cells declined with the decreased density, or ratio of nucleus size to cell size (N/C ratio). Autoradiographic analysis showed that the decrease in DNA synthesis activity was due to the accumulation of "unlabeled" cells, which exhibited a much lower N/C ratio than "labeled" cells. Dexamethasone treat-ment also caused specific reduction in the proportion of S phase cells. These results indicate that M1 cell differentiation is closely coupled with the cessation of DNA synthesis.View full abstractDownload PDF (1044K) -
Minoru Amano, Kiyohiro Hamatani1981 Volume 6 Issue 2 Pages 159-166
Published: 1981
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSIt was attempted to assess the life span of tritiated deoxycyti-dine ([3H]CdR) labeled lymphocytes after intravenous transfusion into young rats and compare their homing pattern with previous results obtained with tritiated thymidine ([3H]TdR) labeled lymphocytes. Only cortical thymocytes were labeled by administering [3H]CdR according to Weissman's transcapsular route. Such labeled cortical thymocytes were transfused intravenously into young recipient rats. The results obtained from these experiments showed that almost all labeled cells disappeared within 24 h after transfusion and practically no labeled cells were detected in the thoracic duct lymph (TDL). Minutes after the transfusion, many labeled lymphocytes were found in the lung, liver, bone marrow and kidney but 24 h later only the spleen contained a certain number of labeled cells, mainly in T-dependent areas and the red pulp. At later times, practically all labeled cells had disappeared. These observations indicate that [3H]CdR labeled cortical thymocytes are short lived and practically none of them recirculate from blood through TDL.View full abstractDownload PDF (1126K) -
Kiyohiro Hamatani1981 Volume 6 Issue 2 Pages 167-179
Published: 1981
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe distribution of cells labeled with generally tritiated de-oxycytidine ([G-3H]CdR) was similar to that of cells labeled with 5-tritium labeled deoxycytidine ([5-3H]CdR) in the thymus and mesenteric lymph nodes. In the thymic cortex and germinal centers of mesenteric lymph nodes, however, radioautographic reactions showed more intense labeling with [G-3H]CdR than with [5-3H]CdR. In the thymic medulla and areas outside the germinal centers, no significant difference in labeling intensity was found between tissue sections labeled with [G-3H]CdR and with [5-3H]CdR. Labeling intensities with tritiated thymidine ([3H]TdR) in the thymic cortex and germinal centers of mesenteric lymph nodes were greatly enhanced by the administration of 5-fluorodeoxyuridine (5-FUdR), whereas those in the thymic medulla and areas outside the germinal centers were only slightly enhanced with 5-FUdR treatment. In the presence of 5-FUdR, the total thymic and mesenteric lymph node cell populations incorporated only little [G-3H]CdR. These results indicate that the lymphocytes which are labeled heavily with [G-3H]CdR in the thymic cortex and germinal centers have the strong metabolic ability to utilize CdR for DNA synthesis, whereas this ability is relatively weak in cells which are labeled strongly with [3H]TdR in the thymic medulla and areas outside the germinal centers.View full abstractDownload PDF (1600K) -
Kiyoshi Ueda, Hiroshi Nakayasu1981 Volume 6 Issue 2 Pages 181-190
Published: 1981
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSA nuclear matrix was obtained from isolated nuclei of bovine lymphocyte by digestion with DNase I and subsequent extractions with 0.4 M and 2.0 M NaCl. 91.1 % of the nuclear protein, 99.5 % of the DNA and 83.1 % of the RNA were removed from isolated nuclei by these treatments. with the following nuclease digestion, almost all residual DNA and RNA was removed leaving the nuclear protein matrix.
Ultrastructural analysis of the nuclear matrix revealed a spherical structure containing a peripheral lamina, an internal fibrogranular network and residual nucleoli.
Sodium dodecyl sulfate polyacrylamide gel electrophoresis of the nuclear matrix demonstrated three major polypeptides of 68, 000, 53, 000 and 43, 000 dalton as well as more than 50 minor polypeptides of various molecular weight classes. The 68, 000 dalton polypeptide corresponds to lamin B, one of three predominant polypeptide components of rat liver nuclear matrix. However, polypeptides corresponding to lamin A and C were not detectable in the bovine lymphocyte nuclear matrix. Hiroshi NakayasuView full abstractDownload PDF (1011K) -
Noriaki Takeguchi, Tadashi Kashiwagura, Magotoshi Morii1981 Volume 6 Issue 2 Pages 191-200
Published: 1981
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSIn the presence of both ATP and Mg++, the density of the negative charge on the external surface of hog gastric vesicles had a higher (absolute) value in comparison to values in the presence of ATP only or the absence of both ATP and Mg++ as seen from the electrophoretic mobilities measured with a conventional cytopherometer. Gastric vesicle-coated particles of n-alkanes or n-alky1 halides were used for the study, in which their surfaces were examined under differential interference-contrast microscopy. This showed that the surfaces were coated by the vesicles. On the addition of Mg-ATP, an increase in the density of the surface charge took place irrespective of the oil used. With n-alkyl bromide (<0.1 % v/v), reorganization of the vesicular structure was indicated from the measurements of proton uptake by the vesicles. This uptake was followed by an increase in the proton leakiness of the membrane. This is evidence that the increased density of the negative charge of the vesicle surface is not due to the proton gradient but with most to phosphorylation of the K+-ATPase in the gastric vesicles. The temperature dependence of the viscosity-corrected electrophoretic mobility showed that there was some transition about 23°C in the presence of Mg-ATP, but not in the absence of Mg-ATP.View full abstractDownload PDF (1045K)
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