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Volume 20 (1995)
- Issue 6 Pages 415-
- Issue 5 Pages 301-
- Issue 4 Pages 245-
- Issue 3 Pages 185-
- Issue 2 Pages 117-
- Issue 1 Pages 1-
Volume 20, Issue 4
Displaying 1-7 of 7 articles from this issue
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Masako Kasami, Tadayoshi Uezato, Yi-Xin Wu, Yasuhisa Naito, Hidehiko O ...1995 Volume 20 Issue 4 Pages 245-252
Published: 1995
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSTo study the structural components of microvilli of the KATO-III cell, we used anti-villin, -ezrin, and anti-MVM (microvillous membrane prepared against mouse intestinal microvilli) antibodies. Villin and ezrin cross-link actin bundles of microvilli such as those in the small intestine and renal proximal cells. Electromicroscopically, the cytoskeletal core of microvilli of the KATO-III cell was constituted of actin-filament bundles. The anti-villin antibody but not anti-ezrin antibody reacted with the KATO-III cell as demonstrated by FITC-immunofluorescence and PAP-staining. Anti-villin, anti-MVM, but not anti-ezrin antibody, reacted with the KATO-III cell surface and with intracellular materials. Western blot analysis using anti-villin and anti-MVM antibodies revealed proteins of -95 kDa (villin), and 15 kDa in the microsomal membrane fractions of KATO-III cells, respectively. Immunocytochemical and confocal laser microscopic studies showed that the cell-surface and the intracellular microcysts of KATO-III cells were preferentially decorated by anti-villin and anti-MVM antibodies. These data suggested that some actin-binding proteins, such as villin, were localized at the cell surface and on some of the intracellular cytoplasmic structures of the KATO-III cell.View full abstractDownload PDF (6670K) -
Suinito Koshida, Mariko Kurasawa, Masahiro Yasuda, Naruki Sato, Takash ...1995 Volume 20 Issue 4 Pages 253-261
Published: 1995
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSTo examine the function of C-protein, a thick filament-associated protein of vertebrate striated muscles, during myofibrillogenesis, the Cdna encoding chicken cardiac C-protein and the truncated cDNA were subcloned into a expression vector and introduced into mouse C2 myogenic cells. The expression and assembly of the C-protein was investigated by immunofluorescence methods. When the cDNA containing the entire open reading frame was introduced, in C2 myoblasts, the transiently expressed exogenous cardiac C-protein existed only diffusely in the cytoplasm, but it became localized in striated structures together with sarcomeric myosin heavy chains (MHC)in myotubes. To clarify the functional domains of C-protein, the cDNA constructs that lack the regions encoding the C-terminal immunoglobulin (Ig) C2 motif or the N-terminal Ig C2 motif were introduced into C2 cells to produce mutant proteins. The truncated chicken cardiac C-protein, which lacked the C-terminal Ig C2 motif, apparently lost the ability to bind to myosin filaments ; the protein was not assembled into myofibrils but diffused in the cytoplasm even in the myotubes. The protein without N-terminal Ig C2 motif, however, was assembled into sarcomeric structures just as complete protein molecules. From these results, we conclude that 1) the assembly of sarcomeric MHC into myofibrils in myotubes is accompanied with that of cardiac C-protein, and 2) the C-terminal Ig C2 motif is necessary for assembly of cardiac C-protein in sarcomeric structures in the cytoplasm.View full abstractDownload PDF (4204K) -
Su Yu, Masayuki Ozawa, Apala Farhat Naved, Teruo Miyauchi, Hisako Mura ...1995 Volume 20 Issue 4 Pages 263-268
Published: 1995
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSUsing antibodies against pokeweed agglutinin-binding proteins from F9 embryonal carcinoma cells, we isolated a cDNA clone PW29 reacting with the antibody. MRNA hybridizing with the cDNA was 4.7 kb, and was strongly expressed in the testis, brain, kidney and heart as well as in F9 cells. The size of mRNA in the testis was heterogeneous. Sequencing the cDNA clone revealed a putative polypeptide of 70 kDa, which is rich in hydrophilic amino acids and has a characteristic sequence of (GluLys)5. The protein also has an oligoproline motif, which conforms to the rule of binding capability to Src homology region III. The cDNA was translated as a fusion protein with glutathione-S-transferase, and was verified to have calcium binding activity, upon a calcium blot experiment.View full abstractDownload PDF (2174K) -
Yasuko Tomono, Chiharu Moritoh, Tatsuji Yasuda, Tohru Okigaki1995 Volume 20 Issue 4 Pages 269-274
Published: 1995
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSGanglioside GM3, one of acidic components of membrane glycosphingolipids (GSL), has been known to change its content quantitatively during growth and differentiation of various cells in vitro.
Detailed analysis of lipid portion of GM3 of rat renal glomerular SGE1 cells revealed that fatty acids with long carbon chains, especially that of C24 : 0 and C24 : 1 increased, while that of short C18 : 0 and C20 : 0 decreased after spontaneous dome formation.
Since not only fatty acid composition of neutral GSL, sulfatide and phospholipid but also composition of long-chain bases (LCB) did not change, it was suggested that only C24 fatty acid of GM3 specifically increased in relation to dome formation.
The spontaneous dome formation has been reported to be related with induction of cellular differentiation in many transporting epithelial cells. We thus assume that the change of fatty acid composition of GM3 is involved in cellular differentiation of SGE1 cells.View full abstractDownload PDF (1970K) -
Helene S. Barbosa, Maria Nazareth L. Meirelles1995 Volume 20 Issue 4 Pages 275-284
Published: 1995
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSThe participation of heart muscle cells (HMC) cytoskeleton during its interaction with Trypanosoma cruzi was investigated. Pre-treatment of heart muscle cells with cytochalasin B (CB) or D (CD) prior to 1 and 3 h of interaction with T. cruzi inhibited the uptake of parasites by about 65% and 75%. T. cruzi was not able to invade fixed HMC, and fixed parasites were not internalized in either normal and CD-treated HMC. Transmission electron microscopy showed cell membrane projections of HMC enclosing the parasite during the invasion process after short periods of interaction (5 to 30 min). During the parasite internalization process, sarcolemma extensions were observed inside the cytoplasmic vacuole, suggesting that the endocytic event may involve internalization of a "self membrane". Images of cytoskeleton elements mobilization during T. cruzi penetration of HMC were obtained following treatment of cells with Triton X-100. Our results suggest an active involvement of HMC cytoskeleton elements during the interiorization of metacyclic forms of T. cruzi.View full abstractDownload PDF (11295K) -
Kazunori Yamaguchi, Masayuki Kobayashi, Yukika Yamauchi, Akiko Tanaka, ...1995 Volume 20 Issue 4 Pages 285-291
Published: 1995
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSTemperature-sensitive (ts) cell cycle mutant mouse cell, tsFT20, is deficient in DNA polymerase α activity to initiate DNA replication at replicon origins. Here, we analyzed phenotypes concerning growth control genes in the arrested tsFT20 cells. Analysis of cyclins showed that expression levels of cyclin D1, which is essential for G1/S transition, remarkably decreased in the mutant cells after temperature up-shift. Further we examined phosphorylation states of retinoblastoma protein (PRB) in the cells. Though the tsFT20 cells arrested in G1/S-S phase at nonpermissive temperature (Eki et al., (1990) J. Biol. Chem. 265 26-33), a large proportion of pRB was found as an underphosphorylated growth-suppressive form in the arrested cells. In revertant cell lines of tsFT20, PRB was not underphosphorylated even at nonpermissive temperature. The pRB underphosphorylation occurred later than the decrease of mRNA levels of cyclin D1, thus the underphosphorylation may be caused by the decrease in amount of cyclin D1 protein. These results indicated that the mutational inactivation of DNA polymerase α evokes phenotypes in which the inhibitory machinery of G1/S transition has been turned on.View full abstractDownload PDF (1775K) -
Tadayuki Ohta, Masanari Matsuda1995 Volume 20 Issue 4 Pages 293-300
Published: 1995
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSThe morphology and intramembranous particle (IMP) distribution of spermatozoa were investigated in four species of cyprinid fishes, Gnathopogon elongatus elongatus, Pseudogobio esocinus, Acheilognathus lanceolatus and Puntius tetrazona. In particular, observation of IMP distribution was conducted as an aspect of comparative spermatology in cyprinid fishes and was continued from a previous paper (Ohta et al., 1994 (8)). Although the fundamental structures of the spermatozoa were similar among the four species, the distribution of IMPs varied. Hexagonal (or parallelogrammic) arrays of IMPs on the sperm head membranes were present in G. elongatus elongatus, A. lanceolatus and P. tetrazona, but not in P. esocinus. The hexagonal arrays have now been confirmed to be present in twelve of the thirteen species of cyprinid fishes examined so far.View full abstractDownload PDF (8391K)
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