Cover photograph (Copyright © 2001, American Society for Microbiology. All rights reserved.): Pseudocolored confocal micrograph of a polykaryon induced by coexpression of varicella-zoster virus (VZV) glycoproteins gE and gB. HeLa cells infected with a double-recombinant vaccinia virus containing gE and gB were labeled with appropriate antibodies against the glycoproteins. Fluorolabeled nuclei are visible at the center of the syncytia as densely colored circles, while VZV gE and gB colocalize throughout the cell in cytoplasmic vesicles and cell membranes. The fluorescent signal of the glycoproteins was pseudocolored in Adobe Photoshop. When coexpressed, VZV gE and gB were found to induce cell-to-cell fusion, forming a large polykaryon similar to those observed in VZV-infected cells. (See related article in October 2001: vol. 75, issue 19, p. 9483.)