FIG. 5.

Tn insertion mutants show random insertions within chosen genes. Lane 1, HindIII digest of the AD169-BAC DNA isolated from bacteria; UL100 (gM) is located on the 6.6-kbp HindIII R fragment (black arrow, white arrowhead); lanes 2 to 4, BAC mutants with insertions into UL100 digested with HindIII; the exact nucleotide positions of the Tn insertion are indicated above the lanes; lane 5, NotI digest of parental AD169-BAC; genes UL74 (gO) and UL75 (gH) are located on a 9.0-kbp NotI fragment (black arrow, white arrowhead); lanes 6 to 13, NotI digest of AD169-BAC-derived genomic HCMV mutants carrying Tn insertions in the genes coding for gH and gO. DNA fragments were separated on a 0.6% agarose gel, and molecular size markers are given in kilobase pairs on either side. Grey arrows, Tn-specific 1.8-kbp fragments; dots, subfragments resulting from cleavage of restriction endonuclease fragments.