Nucleotide sequence changes in thymidine kinase gene of herpes simplex virus type 2 clones from an isolate of a patient treated with acyclovir.
To identify the nucleotide changes that occur in drug-induced thymidine kinase (TK) mutants of herpes simplex virus type 2 (HSV-2), we compared the nucleotide sequences of the tk genes of two mutant HSV-2 clones isolated from a patient who had been treated with acyclovir [9-(2-hydroxyethoxymethyl)guanine; ACV] with the nucleotide sequence of the parental TK+ HSV-2(8703) strain isolated from the same patient. One of the mutants, TK-altered (TKA) HSV-2(9637), was ACV resistant but induced the incorporation of [14C]thymidine into the DNA of infected rabbit skin cells. The nucleotide sequence of the tk gene of mutant TKA HSV-2(9637) had a single change (G to A) at nucleotide 668, which would cause an arginine-to-histidine substitution at amino acid residue 223 of the TK polypeptide. The second ACV-resistant mutant, TK- HSV-2(8710), did not induce detectable incorporation of [14C]thymidine into the DNA of infected rabbit skin cells. This mutant exhibited a deletion of a single base at nucleotide 217 of its nucleotide sequence. This deletion would cause a frameshift mutation at amino acid residue 73 and chain termination at amino acid residue 86 of the TK polypeptide. The nucleotide sequence of TK+ HSV-2(8703) was the same as that of the laboratory strain, TK+ HSV-2(333). The nucleotide sequence of a bromodeoxyuridine-resistant TK- HSV-2(333) mutant of TK+ HSV-2(333) also exhibited a single-base deletion, but at nucleotide 439. This deletion would cause a frameshift mutation at amino acid residue 147 and chain termination at amino acid residue 182. The frameshift mutations of TK- HSV(8710) and TK- HSV-2(333), respectively, occurred in sequences in which C was repeated three times and G was repeated seven times. The results raise the possibility that TK- frameshift mutations of HSV-2 may be common.
Kit
S
S
Division of Biochemical Virology, Baylor College of Medicine, Houston, Texas 77030.
Sheppard
M
M
Ichimura
H
H
Nusinoff-Lehrman
S
S
Ellis
M N
MN
Fyfe
J A
JA
Otsuka
H
H
D000212:Acyclovir / Q000494:pharmacology*; D001345:Autoradiography; D001483:Base Sequence; D002478:Cells, Cultured; D003001:Cloning, Molecular; D005814:Genes, Viral; D006801:Humans; D018139:Simplexvirus / Q000201:enzymology* / Q000235:genetics; D013937:Thymidine Kinase / Q000235:genetics*
D013937:Thymidine Kinase; D000212:Acyclovir