Open AccessA point mutation in the human cytomegalovirus DNA polymerase gene confers resistance to ganciclovir and phosphonylmethoxyalkyl derivatives
Author(s) -
Veronica Sullivan,
Karen K. Biron,
Christine L. Talarico,
Sylvia C. Stanat,
M. R. Davis,
Lu-Ann M. Pozzi,
Donald M. Coen
Publication year - 1993
Publication title -
antimicrobial agents and chemotherapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.07
H-Index - 259
eISSN - 1070-6283
pISSN - 0066-4804
DOI - 10.1128/aac.37.1.19
Subject(s) - ganciclovir , dna polymerase , human cytomegalovirus , biology , polymerase , cytosine , microbiology and biotechnology , point mutation , mutant , primer (cosmetics) , recombinant dna , gene , virology , mutation , dna , genetics , chemistry , organic chemistry
Ganciclovir-resistant mutant 759rD100 derived from human cytomegalovirus strain AD169 contains two resistance mutations, one of which is in the UL97 gene and results in decreased ganciclovir phosphorylation in infected cells [V. Sullivan, C. L. Talarico, S. C. Stanat, M. Davis, D. M. Coen, and K. K. Biron, Nature (London) 358:162-164, 1992]. In the present study, we mapped the second mutation to a 4.1-kb DNA fragment containing the DNA polymerase gene and showed that it confers ganciclovir resistance without impairing phosphorylation. Sequence analysis of the 4.1-kb region revealed a single nucleotide change that resulted in a glycine-to-alanine substitution at position 987 within conserved region V of the DNA polymerase. Recombinant viruses constructed to contain the DNA polymerase mutation but not the phosphorylation defect displayed intermediate resistance (4- to 6-fold) to ganciclovir relative to the original mutant 759rD100 (22-fold); the recombinant viruses also displayed resistance to ganciclovir cyclic phosphate (7-fold), 1-(dihydroxy-2-propoxymethyl)-cytosine (12-fold), and the phosphonylmethoxyalkyl derivatives (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)adenine and (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine (8- to 10-fold). However, the recombinant viruses remained susceptible to certain related compounds. These results imply that the human cytomegalovirus DNA polymerase is a selective target for the antiviral activities of ganciclovir, certain of its derivatives and phosphonomethoxyalkyl derivatives; support a role for region V in substrate recognition; and suggest the possibility of clinical resistance of human cytomegalovirus to these compounds because of polymerase mutations.