Identification and characterization of a novel neural cell adhesion molecule (NCAM)-associated protein from quail myoblasts: relationship to myotube formation and induction of neurite-like protrusions.

We identified a novel neural cell adhesion molecule (NCAM)-associated protein, myogenesis-related and NCAM-associated protein (MYONAP), the expression of which increases during the formation of myotubes in quail myoblasts transformed with a temperature-sensitive mutant of Rous sarcoma virus (QM-RSV cells). MYONAP shares homology with PL48 in human cytotrophoblasts and KIAA0386 in human brain. Excess expression of MYONAP in presumptive QM-RSV myoblasts induced long protrusions like neurites in cooperation with microtubules.

Specific binding of heat shock protein 70 with HN-protein inhibits the HN-protein assembly in Sendai virus-infected Vero cells.

The production of hemagglutinating virus of Japan (HVJ; Sendai virus) was inhibited at 41 degrees C, whereas it was normal at 37 degrees C. In the infected Vero cells, viral specific proteins were synthesized even at 41 degrees C, but the synthesized HN protein was not integrated into the cell membrane, resulting in the inhibition of viral production. To investigate the relationship of HSP70 to the inhibition of HN-protein integration, the expression of HSP70 was induced by prostaglandin A1 (PGA1) at 37 degrees C, and the influence on viral infection was examined.

[Relationship of HSP70 to temperature-dependency of influenza viral infection].

The influenza virus copies its genomic RNA in the nuclei of host cells, but the viral particles are formed at the plasma membrane. Thus the export of a new genome from the nucleus into the cytoplasm is essential for viral production. Several viral proteins, such as nucleoprotein (NP), RNA polymerases, and matrix protein 1 (M1), synthesized in the cytoplasm are imported into the nucleus and form a viral ribonucleoprotein complex (vRNP) with new genomic RNA.

Formation and characterization of spontaneously formed heterokaryons between quail myoblasts and 3T3-L1 preadipocytes: correlation between differential plasticity and degree of differentiation.

Skeletal muscle cells and adipose cells have a close relationship in developmental lineage. Our previous study has shown that the heterokaryons between quail myoblasts and undifferentiated 3T3-L1 cells (preadipocytes) normally differentiated into myotubes, whereas the heterokaryons between myoblasts and differentiated 3T3-L1 cells (adipocytes) failed myogenic differentiation. These results suggest differences between preadipocytes and adipocytes.

Heat shock protein 70 is related to thermal inhibition of nuclear export of the influenza virus ribonucleoprotein complex.

The influenza virus genome replicates and forms a viral ribonucleoprotein complex (vRNP) with nucleoprotein (NP) and RNA polymerases in the nuclei of host cells. vRNP is then exported into the cytoplasm for viral morphogenesis at the cell membrane. Matrix protein 1 (M1) and nonstructural protein 2/nuclear export protein (NS2/NEP) work in the nuclear export of vRNP by associating with it.

Characterization of temperature-sensitive HVJ (Sendai virus) infection in Vero cells: inhibitory mechanism of viral production at 41 degrees.

In a previous study, it was found that the synthesis of hemagglutinating virus of Japan (HVJ; Sendai virus)-specific proteins was inhibited at the transcriptional level at 41 degrees in LLC-MK2 cells. During an investigation of the temperature sensitivity of HVJ production in other host cells, the synthesis of HVJ-specific proteins was recognized even at 41 degrees in Vero cells. Viral production, however, was not detected, indicating the inhibition of steps after the synthesis of viral proteins.

Characterization of heterokaryons between skeletal myoblasts and preadipocytes: myogenic potential of 3T3-L1 preadipocytes.

It has been shown previously that heterokaryons between myoblasts and non-myogenic cells disturb myogenic differentiation (Hirayama et al. (2001); Cell Struct. Funct.

Nuclear export of influenza viral ribonucleoprotein is temperature-dependently inhibited by dissociation of viral matrix protein.

The influenza virus copies its genomic RNA in the nuclei of host cells, but the viral particles are formed at the plasma membrane. Thus, the export of new genome from the nucleus into the cytoplasm is essential for viral production. Several viral proteins, such as nucleoprotein (NP) and RNA polymerases, synthesized in the cytoplasm, are imported into the nucleus, and form viral ribonucleoprotein (vRNP) with new genomic RNA.

An absorption-based surface plasmon resonance sensor applied to sodium ion sensing based on an ion-selective optode membrane.

A surface plasmon resonance (SPR) sodium ion sensor using an ion optode membrane film was experimentally and theoretically described based on an absorption-based SPR principle proposed in our previous article (Kurihara, K; Suzuki, K. AnaL Chem. 2002, 74, 696-701).

Lonophore-based lithium ion film optode realizing multiple color variations utilizing digital color analysis.

Digital color analysis (DCA), utilizing colors themselves or digital information of colors, can not only be applied to various quantitative analysis using chromaticity coordinates but can also be used to develop suitable sensors for visual colorimetry based on the characteristics of human visual perception by virtual simulations based on digital color information. To achieve a clear visual color variation for lithium ion determination, we designed and prepared a color-changeable film sensor (film optode) by the use of two kinds of lipophilic dyes, KD-C4 and KD-M11, whose colors and pKa values are different. This film sensor is a plasticized PVC membrane containing the mixture of two kinds of dyes with the lithium ionophore TTD14C4 and the lipophilic anionic additive tetrakis-[3,5-bis(trisfluoromethyl)phenyl]borate sodium salt dihydrate.

Temperature-sensitive viral infection: inhibition of hemagglutinating virus of Japan (Sendai virus) infection at 41 degrees.

While investigating myoblast fusion using enveloped viruses, we unexpectedly found that the production of hemagglutinating virus of Japan (HVJ; Sendai virus) was suppressed temperature dependently in quail myoblasts transformed with a temperature-sensitive Rous sarcoma virus, which proliferate at 35.5 degrees but differentiate at 41 degrees; viral production was normal at 35.5 degrees but suppressed at 41 degrees irrespective of the species of host cells.

Changes in fused cells induced by hvj (sendai virus): relationship of morphological changes to endocytosis of the surface membrane.

Fused Ehlrich ascites tumor (EAT) cells induced by hemagglutinating virus of Japan (HVJ; Sendai virus) had an irregular shape, reflecting the shape of cell aggregates before fusion. During subsequent culture, the fused cells gradually took on a spherical form within 60 min. Examination of the fused cells revealed a vigorous endocytosis of the cell membrane during the morphological change.

Changes in fused cells induced by hvj (sendai virus): redistribution of cytoplasmic organelles and cytoskeletal reorganization.

To understand the relationship between the location of organelles and cellular function, we examined the dynamic state of cytoplasmic organelles and cytoskeleton in polynuclear Ehrlich ascites tumor (EAT) cells fused with hemagglutinating virus of Japan (HVJ; Sendai virus) by confocal laser scanning microscopy. Irregular fused cells gradually became spherical during culture, and nuclei and mitochondria were redistributed in the fused cell; nuclei formed a cluster surrounded by mitochondria. F-actin, vimentin, and microtubules were also reorganized with the redistribution of cell organelles.