Chromatin pattern consisting of repeating bipartite structures in WI-38 cells infected with human cytomegalovirus.

A novel chromatin structural pattern displaying bipartite and oblate ellipsoid structures orderly arranged along a fiber axis has been observed in WI-38 cells infected with human cytomegalovirus. This chromatin type coexists with chromatin fibers showing conventional nucleosomes. Each bipartite-oblate structure is 40 nm in length, about four times as long as an ordinary nucleosome, and the number of these structures per micrometer (11/micrometer) is clearly less than that of typical cellular nucleosomes (32/micrometer).