Structure and expression of murine cytomegalovirus immediate-early gene 2

The immediate-early gene ie2 of murine cytomegalovirus was characterized. The 1.75-kb ie2 transcript is spliced from three exons, of 78, 124, and 1,283 nucleotides, which are separated by introns of 1,245 and 364 nucleotides. An ATG codon located in the third exon leads into an open reading frame of 391 codons. Immediate-early expression of the predicted polypeptide was confirmed by immunoprecipitation of a 43-kDa protein by using an antiserum raised against a bacterial fusion protein. The predicted IE2 amino acid sequence has regions with similarity to amino acid sequences of members of the human cytomegalovirus US22 family.