Multinucleate syncytia

Effect of Ascorbate on Vims Replication in Freshly Infected Cells, To extend these findings to freshly infected cells, we investigated the effects of ascorbate on acute HIV infection of susceptible CIW T lymphocytes. Viral infectivity and cytopathic effect in these cells have been correlated with formation of giant cell syncytia mediated by interaction of HIV envelope glycoprotein with CD4 cell surface receptor (14, 20, 21). In controls, multinucleated syncytia became visible by day 4 and reached high levels on day 6. The continuous presence of ascorbate caused a dose- and time-dependent decrease in syncytium formation. On day 4, 93.3% inhibition in syncytia number was seen with ascorbate at 100 /tg/ml (Fig. 6). At this concentration, ascorbate did not inhibit the growth of uninfected VB cells (99% survival by trypan blue dye exclusion), indicating that the... 

The results of experiments In which active myosin II is eliminated from the cell demonstrate that cytokinesis is indeed dependent on myosin II (Figure 19-21). In one type of experiment, antl-myosin II antibodies are microinjected into one cell of a sea urchin embryo at the two-cell stage. In other experiments, expression of myosin II Is Inhibited by deletion of the myosin gene or by antisense Inhibition of myosin mRNA expression. In all cases, a cell lacking myosin II replicates to form a multinucleated syncytium because cytokinesis, but not chromosome separation, Is Inhibited. Without myosin II, cells fail to assemble a contractile ring, although other events in the cell cycle proceed normally. 

Jones, M.G.K. and Northcote, D.H. (1972) Nematode-induced syncytium -a multinucleate transfer ceil. Journal of Cell Science 10, 789-809. 

As myoblasts proliferate and migrate, say, to a developing limb bud, they become aligned, stop dividing, and fuse to form a syncytium (a cell containing many nuclei but sharing a common cytoplasm). We refer to this multinucleate cell as a myotube. Concomitant with cell fusion Is a dramatic rise In the expression of genes necessary for further muscle development and function. 

Syncytium (plural syncytia). A multinucle-ate mass in a cell culture, for example, caused by the respiratory syncytial virus. 

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