Colocalization of the Herpes Simplex Virus 1 U(L)4 Protein with Infected Cell Protein 22 in Small, Dense Nuclear Structures Formed prior to Onset of DNA Synthesis

Herpes simplex virus 1 infected cell protein 22 (ICP22) localizes in small, dense nuclear bodies of primate cells early in infection and in the more diffuse replicative complexes after the onset of DNA synthesis. U(L)4, a γ(2) protein, localizes in cytoplasm and in the small nuclear structures containing ICP22 but not in replicative complexes. In rabbit skin cells, both ICP22 and U(L)4 localize in the dense nuclear bodies late in infection. The results suggest that the small nuclear structures perform a function involving both proteins late in infection.