Phylogenetic analysis of clinical herpes simplex virus type 1 isolates identified three genetic groups and recombinant viruses.

• Herpes simplex virus type 1 (HSV-1) is a ubiquitous human pathogen which establishes lifelong infections. In the present study, we determined the sequence diversity of the complete genes coding for glycoproteins G (gG), I (gI), and E (gE), comprising 2.3% of the HSV-1 genome and located within the unique short (US) region, for 28 clinical HSV-1 isolates inducing oral lesions, genital lesions, or encephalitis. Laboratory strains F and KOS321 were sequenced in parallel. Phylogenetic analysis, including analysis of laboratory strain 17 (GenBank), revealed that the sequences were separated into three genetic groups. The identification of different genogroups facilitated the detection of recombinant viruses by using specific nucleotide substitutions as recombination markers. Seven of the isolates and strain 17 displayed sequences consistent with intergenic recombination, and at least four isolates were intragenic recombinants. The observed frequency of recombination based on an analysis of a short stretch of the US region suggests that most full-length HSV-1 genomes consist of a mosaic of segments from different genetic groups. Polymorphic tandem repeat regions, consisting of two to eight blocks of 21 nucleotides in the gI gene and seven to eight repeats of 3 nucleotides in the gG gene, were also detected. Laboratory strain KOS321 displayed a frameshift mutation in the gI gene with a subsequent alteration of the deduced intracellular portion of the protein. The presence of polymorphic tandem repeat regions and the different genogroup identities can be used for molecular epidemiology studies and for further detection of recombination in the HSV-1 genome.

Nyckelord

Base Sequence

DNA

Viral

chemistry

Encephalitis

virology

Epidemiology

Molecular

Female

Frameshift Mutation

Genitalia

virology

Genotype

Herpes Simplex

virology

Herpesvirus 1

Human

classification

genetics

isolation & purification

Humans

Male

Molecular Sequence Data

Mouth

virology

Phylogeny

Polymorphism

Genetic

Recombination

Genetic

Sequence Analysis

DNA

Sequence Homology

Tandem Repeat Sequences

Viral Envelope Proteins

genetics

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