Figure 2.

Transmission electron microscopy (EM) microphotographs of fibroblasts infected with the CIDMTR Strain of GPCMV. (A) Plastic embedded preparation contrasted with uranyl acetate/lead citrate of two enlarged fibroblasts showing cell intranuclear and cytoplasmic viral inclusions and numerous dense bodies (white arrowheads) in the intercellular space (bar = 10 µm). (B) Magnification of another CIDMTR-infected cell revealed nuclear (N) viral replication and nucleocapsid assembly sites (small square), as well as a large maturation site (asterisk) and dense body formation in the cytoplasm (large square, bar = 2 µm). (C) Additional magnification in which replication and capsid assembly in the nucleus (small square) is appreciated; note empty capsids (arrow) and DNA containing nucleocapsids (arrowhead; bar = 0.5 µm). (D) Magnification of virus maturation sites within the cytoplasm (large square in panel (B)) reveals electron dense material formed by aggregation of nucleocapsids and cell organelles such as Golgi systems, endoplasmic reticulum and vesicles (bar = 0.5 µm). (E) Capsid is demonstrated becoming coated with tegument proteins and then acquiring its final envelope by budding into vesicles (arrows; bar = 0.5 µm). (F) Several dense bodies are present in the intercellular space (bar = 0.5 µm). (G) Negative contrast preparation of enveloped B-capsid (arrow) and dense body (asterisk, bar = 0.5 µm) is demonstrated. (H) EM of strain 22122-infected cells demonstrating virtually identical morphology; A, B and C capsids are identified as described in text.