Analysis of the thymidine kinase of a herpes simplex virus type 1 isolate that exhibits resistance to (E)-5-(2-bromovinyl)-2'-deoxyuridine.
The mechanism responsible for the decreased sensitivity of a clinical herpes simplex virus type 1 (HSV-1) isolate, HSV-145, to (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU) was examined. Measurements of 50% inhibitory doses of several drugs demonstrated that although HSV-145 was sensitive to phosphonoacetic acid, adenine arabinoside and acyclovir, its sensitivity to BVDU and 5-(2-chloroethyl)-2'-deoxyuridine was significantly less than that normally observed for HSV-1. Analysis of the thymidylate kinase (TMP-K) activity of HSV-145 thymidine kinase (TK) demonstrated a decreased level of TMP-K activity when compared to HSV-1 TK. The TMP-K activity of HSV-145 resembled that observed for HSV-2 and the TK-deficient strain HSV-1 TK-7. When the nucleotide sequence of the HSV-145 TK gene was compared to that of the HSV-1 strains C1(101) and SC16 a single nucleotide substitution (G changed to A at base position 502) was detected which would result in the substitution of threonine at amino acid position 168 for alanine. The substitution is the same as that for the laboratory-derived BVDU-resistant virus HSV-1 SC16B3. Collectively, these studies highlight the importance of amino acid conservation at position 168 of the HSV-1 TK in conferring efficient TMP-K activity and BVDU sensitivity.
Department of Microbiology/Immunology, Northeastern Ohio Universities College of Medicine, Rootstown 44272.
B A
BA
Wilber
J J
JJ
Docherty
D000212:Acyclovir / Q000494:pharmacology; D000595:Amino Acid Sequence; D000998:Antiviral Agents / Q000378:metabolism / Q000494:pharmacology*; D001483:Base Sequence; D001665:Binding Sites; D001973:Bromodeoxyuridine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D003857:Deoxyuridine / Q000031:analogs & derivatives / Q000494:pharmacology; D004352:Drug Resistance, Microbial; D018259:Herpesvirus 1, Human / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D010746:Phosphonoacetic Acid / Q000494:pharmacology; D010766:Phosphorylation; D017354:Point Mutation / Q000235:genetics; D017422:Sequence Analysis, DNA; D013936:Thymidine / Q000378:metabolism; D013937:Thymidine Kinase / Q000235:genetics / Q000378:metabolism; D014740:Vidarabine / Q000494:pharmacology
D000998:Antiviral Agents; C020235:brivudine; C047370:5-(2-chloroethyl)-2'-deoxyuridine; D013937:Thymidine Kinase; D014740:Vidarabine; D001973:Bromodeoxyuridine; D010746:Phosphonoacetic Acid; D013936:Thymidine; D003857:Deoxyuridine; D000212:Acyclovir