INHIBITION OF HERPESVIRUS DNA SYNTHESIS BY 9‐β‐D‐ARABINOFURANOSYLADENINE IN CELLULAR AND CELL‐FREE SYSTEMS *

Abstract

9-beta-D-Arabinofuranosyladenine 5'-triphosphate (ara-ATP) is an inhibitor both of DNA polymerase-alpha and -beta from noninfected rabbit kidney cells and of the DNA-dependent DNA polymerase induced by herpes simplex virus Type 1 (strain IES). The studies were performed with partially purified enzymes, and each of the different polymerase preparations contained only one DNA-dependent DNA polymerase species. These enzymes were inhibited in a competitive manner. The HSV-induced DNA-dependent DNA polymerase was 39-fold more sensitive to ara-ATP than was cellular DNA polymerase-beta and 116-fold more sensitive than cellular DNA polymerase-alpha. The affinity of the HSV-induced enzyme for ara-ATP was only slightly influenced by the use of different template/initiators in the enzyme assays. In intact cell systems DNA synthesis was affected by 9-beta-D-arabinofuranosyladenine (ara-A) as indicated by the reduced incorporation of deoxythymidine. In herpesvirus-(strain Lennette)-infected cells, however, ara-A shows no influence on the incorporation on deoxythymidine into cellular DNA, but it substantially reduces the incorporation into viral DNA. Ara-A itself is incorporated into both cellular and herpesviral (strain Lennette, D-316 and IES) DNA during DNA synthesis.

Characterization of Ribonucleotide Reductase Induction in BHK-21/C13 Syrian Hamster Cell Line Upon Infection by Herpes Simplex Virus (HSV)

“…Our finding that araATP also was not an inhibitor of the HSV-induced reductase supports the hypothesis that the primary site of action for araA in the inhibition of HSV DNA synthesis is located at the level of the HSV DNA polymerase activity (Muller et al, 1977).…”

“…Inhibition by araA TP AraA has been described as a good inhibitor of HSV replication (Sidwell et al, 1968) and it is believed that the phosphorylated derivative of this nucleotide analogue blocks the HSV DNA polymerase (Muller et al, 1977). However, it has been also reported that araATP could interfere with ribonucleotide reductase activity (Moore & Cohen, 1967); therefore, a high sensitivity of HSV-induced ribonucleotide reductase could contribute to the toxicity of araA for HSV.…”

T-T-cell interactions during the vitro cytotoxic allograft responses. I. Soluble products from activated Lyl+ T cells trigger autonomously antigen-primed Ly23+ T cells to cell proliferation and cytolytic activity.

“…2), the metabolic requirements for the production of SCIF were studied . Before Con A stimulation splenic lymphocytes were treated either with mitomycin C (to block DNA synthesis [ 18]), 9-B-D-Ara A to block DNA synthesis (19), and emetine (to block protein synthesis [20]) at concentrations previously calibrated for selective inhibition of the metabolic pathway in question (Materials and Methods) . Whereas mitomycin C and Ara A treatment did not affect the capacity to produce SCIF, emetine pretreated cells were unable to do so (Table IV) .…”

“…Thereafter the cells were washed twice through FCS . In control experiments, it was demonstrated that Ara A at a final concentration of 5 leg/ml inhibited the DNA-synthesis by more than 90% (19) .…”

Inactivation of S-adenosylhomocysteine hydrolase during adenine arabinoside therapy.

“…Although the basis for the antiviral action of ara-A remains unclear, preferential inhibition of a virus-specific DNA polymerase has been the most widely accepted explanation (1)(2)(3)(4). However, more recent evidence has revealed, in fact, no preferential incorporation into viral DNA (5).…”