ANALYSIS OF A HERPES-SIMPLEX VIRUS TYPE-1 LAT MUTANT WITH A DELETION BETWEEN THE PUTATIVE PROMOTER AND THE 5' END OF THE 2.0-KILOBASE TRANSCRIPT

A herpes simplex virus type 1 strain 17 mutant with a deletion between genomic nucleotides 118880 and 119250 was constructed and called 17 Delta Sty. The deletion removes most of a putative secondary LAT promoter (called LAPII) as well as 370 of the first 449 nucleotides of the proposed 8.5-kb transcript believed to be the precursor of 2.0-kb LAT. 17 Delta Sty was shown to produce major 2.0-kb LATs in tissue culture. Moreover, trigeminal nerves from latently infected mice contained an intact 1.45- to 2.0-kb LAT as well as the minor LATs which are recognized by probes specific for regions downstream of the 2.0-kb LAT. Finally, 17 Delta Sty reactivated with normal kinetics from the trigeminal ganglia of latently infected mice in the explant cocultivation assay and egressed from tissue culture cells as efficiently as wild-type virus. These results clearly show that the region deleted in 17 Delta Sty is dispensable for intact 2-kb LAT production, viral egress in tissue culture, and normal reactivation from latently infected neurons in mice.