RESUMO
In vitro mRNA synthesis of Sendai virus is almost entirely dependent on the addition of cellular proteins (host factors). Previous studies indicated that the host factor activity from bovine brain was resolved into at least two complementary fractions, one of which may be tubulin. In this study, the host factor activity that stimulates the transcription in the presence of tubulin was further purified from bovine brain. This fraction was found to contain at least two complementary factors, and one of them was purified to a single polypeptide chain with an apparent M(r) of 46,000 (p46). From the amino acid sequence, biochemical, and immunological analyses, p46 was identified as a glycolytic enzyme, phosphoglycerate kinase (PGK). Purified native PGK from rabbit and yeast, and a recombinant human PGK substituted for p46. Although, as previously suggested, tubulin was involved in the transcription initiation complex formation by being integrated into the complex, p46 and its complementary factor had little effect on the complex formation. On the other hand, when p46 and the complementary factor were added to the RNA chain elongation reaction from the isolated initiation complex formed with tubulin, mRNA synthesis was dramatically stimulated. The enzymatic activity per se of PGK did not seem to be required for its activity. West-Western blot analysis showed that PGK could directly interact with tubulin. These data suggest that PGK stimulates Sendai virus mRNA synthesis at the elongation step, probably through its interaction with tubulin in the initiation complex.
Assuntos
Regulação Fúngica da Expressão Gênica , Fosfoglicerato Quinase/metabolismo , Respirovirus/genética , Transcrição Gênica , Vírus da Estomatite Vesicular Indiana/genética , Sequência de Aminoácidos , Animais , Encéfalo/metabolismo , Bovinos , Embrião de Galinha , Cromatografia , Cromatografia de Afinidade , Durapatita , Glicólise , Humanos , Camundongos , Dados de Sequência Molecular , Peso Molecular , Fragmentos de Peptídeos/química , Fosfoglicerato Quinase/química , Fosfoglicerato Quinase/isolamento & purificação , RNA Mensageiro/genética , Coelhos , Proteínas Recombinantes/metabolismo , Ribonucleoproteínas/isolamento & purificação , Ribonucleoproteínas/metabolismo , Saccharomyces cerevisiae/enzimologia , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Tubulina (Proteína)/isolamento & purificação , Tubulina (Proteína)/metabolismoRESUMO
The antihepatotoxic effects of ginsenosides, saponins from PANAX GINSENG, and their aglycones were investigated utilizing carbon tetrachloride (CCl (4))- and galactosamine (GalN)-induced cytotoxicity in primary cultured rat hepatocytes. Prominent protective actions were found with 20( S)-ginsenoside-Rh (2), 20( R)-ginsenoside-Rg (3) and prosapogenin of ginsenoside-Ro, 20( R)- and 20( S)-ginsenoside-Rs in CCl (4)-produced cytotoxicity, and 20( S)-ginsenoside-Rh (1) and prosapogenin of 20( S)-ginsenoside-Rs were effective in preventing GalN-induced liver cell damage. The antihepatotoxic effects of chikusetsusaponins, saponins of PANAX JAPONICUS, were also examined. The structure-activity relationship is discussed.
RESUMO
The so-called two-stage procedure has been used in the reconstructive surgery for the severely injured flexor tendon of the finger. However, only little has been known as to vascularity of the grafted tendon within the pseudosheath. In order to clarify this problem, a series of experimental studies were carried out using young chickens. First, the flexor tendon of the fourth digit of chicken with its sheath was replaced by a silicone rod. The distal end of the rod was sutured to the stump of the flexor digitorum profundus and the proximal end left free. Then, in ten to sixteen weeks, upon removal of the rod, the flexor digitorum profundus of the third digit was grafted through into the newly formed pseudosheath. The paw was immobilized with plaster case in moderate flexion for three weeks, then the chicken was allowed to walk freely. At the different time intervals, starting from the third day to the fifteen weeks after surgery, a mode of vascularization of the grafted tendon and its surrounding tissue was examined microangiographically. The vessels appear at the area of proximal and distal stump of the grafted tendon a week postoperatively, and additional vessels appear at the contact area of the pseudosheath and the grafted tendon two weeks postoperatively. These vessels formed mutual anastomosis in five to six weeks. With time, the vessels connecting between the epitenon and the pseudosheath gradually enlarge and assemble together to form vascular bundles, so that the appearance of the structure becomes similar to that of the mesotenon. Three weeks postoperatively, the vessels appeared in the grafted tendon, and grew gradually so that these vessels ran through the full length of the grafted tendon in five to six weeks. About ten weeks, the vascularity of the grafted tendon is more abundant than that of the normal tendon, but diminished gradually so as to resemble that of the normal tendon at the fifteeth week. Thus, the growth of the vessels of the tendon grafted by two-stage procedure is delayed by two weeks compared with that by the primary tendon grafting.
