RT Journal Article SR Electronic(1) A1 Harland, June A1 Brown, S. MoiraYR 1991 T1 Abolition of the RL neurovirulence phenotype of herpes simplex virus type 2 strain HG52 does not require deletion of the DR1 element of the ‘a’ sequence JF Journal of General Virology, VO 72 IS 11 SP 2777 OP 2779 DO https://doi.org/10.1099/0022-1317-72-11-2777 PB Microbiology Society, SN 1465-2099, AB We have characterized a spontaneous variant of herpes simplex virus type 2 (HSV-2) strain HG52, 2616, which has 786 bp of both copies of RL deleted, but which retains 782 bp upstream of the 5′ end of immediate early gene 1 and 463 bp downstream of the ‘a’ sequence. Variant 2616 is avirulent following intracerebral inoculation of BALB/c mice, thus showing in vivo characteristics similar to those of variant 2604, described previously (a 1488 bp deletion incorporating the DR1 element of the ‘a’ sequence), but not to those of variant 2701, which has an intermediate neurovirulence phenotype. The deletions in variants 2616 and 2604 remove the conserved HSV-1 and -2 RL open reading frame entirely and extend downstream from it, whereas the deletion in variant 2701 removes only the 5′ part. The data show that deletion of part of the ‘a’ sequence is not required for the production of the RL avirulence phenotype in HSV-2 strain HG52., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-72-11-2777