Syn strains HSZP and ANGpath [correction of ANG] of herpes simplex virus type 1 do not contain mutations in the regions of UL53 gene relevant to syncytium formation.

Parallel sequencing of UL53 gene of four strains of herpes simplex virus type 1 (HSV-1), two of which (HSZP and ANGpath) were of the syn phenotype while another two (KOS and 17) were of the non-syn phenotype, showed in three strains amino acid mutations unrelated to the already described syn1 glycoprotein K (gK) mutations (Dolter et al., 1994). The only mutations which altered encoded amino acids were found in strains HSZP (Gln to Arg at position 198) and ANGpath (Val to Ile at position 137). Both mutations were localised outside of the two mutation clusters suspected for affecting syncytium formation. In addition, a CG/GC variation was found at positions 245-246 and 669-670. These compressions affected three codons altering amino acids (aa) 82 (Cys or Ser), 223 (Me or Ile) and 224 (Leu or Val), respectively.