Enhancement of herpes simplex virus-induced polykaryocyte formation by 12-O-tetradecanoyl phorbol 13-acetate: Association with the reorganization of actin filaments and cell motility

A morphological change induced by syn- herpes simplex virus type 1 (HSV-1), polykaryocyte formation, was enhanced by treatment with 12-O-tetradecanoyl phorbol 13-acetate (TPA) in A431 cells. TPA treatment decreased the number of stress fibers, but led to the development of spike-like filopodia and a ctin-containing long projections. Similar reorganization of actin filaments was observed in HSV-l-induced polykaryocytes, The actin filament-disruptin g drug cytochalasin D, but not the microtubule-disrupting drug nocodazole, inhibited the effect of TPA on polykaryocyte formation, indicating that the actin microfilament system plays a key role in this event. HSV-1 glycoprot ein D (gD) was present in the cytoplasm of HSV-1-infected cells and gD gene -transfected cells; its expression became prominent at long cell projection s in the presence of TPA, These findings suggest that the reorganization of actin filaments and cell motility are associated with the enhancing effect of TPA on HSV-1-induced polykaryocyte formation, Copyright (C) 2000S, Karg er AG, Basel.