Deletion and Duplication Variants around the Long Repeats of Herpes Simplex Virus Type 1 Strain 17

Abstract

SUMMARYThree variants of herpes simplex virus type 1 strain 17 were isolated. One variant had a deletion of 2-5 x 106 M r in IRL/UL and 0.8 × 106 Mr in TRL such that sequences were deleted from both long repeats. The deletion in UL removed the 20K and 22K open reading frames. The second variant had a deletion of 3.5 × 106Mr in IRL/UL which again removed the 20K and 22K open reading frames. The third variant had a similar deletion in UL, but in this case the deleted sequences were replaced by sequences from the left end Of UL, such that the long repeat was extended by 3 x 106 M r and the overall genome size by 2 × 106 M r. All three variants grew almost normally in vitro, The analysis of 11 isolates with extensive variation in the long repeats outside the 'a' sequence is also reported.

Inhibition of Transient Gene Expression with Plasmids Encoding Herpes Simplex Virus Type 1 UL55 and Alpha Genes

“…In infected cells, a 1.5 kb transcript homologous to ATla and 0-9 and 1.1 kb transcripts homologous to ATlb, have been observed (unpublished results). Similar transcripts have been observed or predicted by others (MacLean & Brown, 1987;Spivack & Fraser, 1988). The 0.9 and 1.1 kb transcripts may encode the polypeptide products predicted by the open reading frames present in the sequences in ATlb called UL55 and UL56 (McGeoch et al, 1988).…”

Evolution and Diversity in Human Herpes Simplex Virus Genomes

“…S2 and Table S1). This type of insertion, from the left side of UL into the UL56 locus, has also been reported in single-plaque isolates of strain 17 (96).…”

“…Deletions in one or both of these genes have been noted in two attenuated strains, namely, HF10, which harbors a deletion in UL56 and a homopolymer-based frameshift in UL55 (47), and HFEM, where restoration of the UL56 gene restored virulence in vivo (97,99). Moreover, HSV-1 strains can harbor mixed populations of mutations in this region, as demonstrated by the isolation of single-plaque variants of HSV-1 strains 17 and K52 that harbor deletions of different sizes (96,101).…”

“…3C). These genes are not required for growth in vitro, but UL56 appears to be important for virulence and the establishment of latency in vivo (95)(96)(97)(98)(99). Deletions in one or both of these genes have been noted in two attenuated strains, namely, HF10, which harbors a deletion in UL56 and a homopolymer-based frameshift in UL55 (47), and HFEM, where restoration of the UL56 gene restored virulence in vivo (97,99).…”

Herpes simplex virus type 1 deletion variants 1714 and 1716 pinpoint neurovirulence-related sequences in Glasgow strain 17+ between immediate early gene 1 and the 'a' sequence

“…] are to be used as unselected markers (Brown et al, 1984;Harland & Brown, 1985;MacLean & Brown, 1987c). The HSV-1 strain 17 + mutant, 1702 (MacLean & Brown, 1987 c) (devoid of the four HSV-1 XbaI sites and tk-), was the parental virus used to remove various HindlII sites by site-directed mutagenesis.…”