An acidic region of the 89K murine cytomegalovirus immediate early protein interacts with DNA

The product of the ie 1 gene, the regulatory immediate early
protein pp89 of murine cytomegalovirus (MCMV), interacts with core
histones, which can mediate the association of pp89 with DNA. We
report the capacity of pp89 to interact directly with DNA in the
absence of cellular proteins. After separation of proteins by
SDS–PAGe, pp89 bound ds- and ssDNA, with a preference for ssDNA.
Binding to specific DNA sequences in the MCMV genome was not
detected. The DNA-binding region of pp89 was located to amino acids
438 to 534 by analysis of deletion mutants expressed as
-galactosidase or TrpE fusion proteins. This region is identical to
the highly acidic C-terminal region spanning amino acids 424 to
532. The human cytomegalovirus IE1 protein, which contains a
similar extended C-terminal acidic region, does not react with DNA
under the same experimental conditions.