ABSTRACT
Cupric complex of isonicotinic acid hydrazide inhibits DNA synthesis by avian myloblastosis virus reverse transcriptase. This inhibition occurs in the presence of either ribonucleotide or deoxyribonucleotide templates. The inhibition of reverse transcriptase by cupric-INH complex is considerably reduced when stored or proteolytically cleaved enzyme was used in the reaction. The complex also inhibits the reverse transciptase-associated RNase Η activity. The cupric-isonicotinic acid hydrazide complex cleaves pBR 322 from I DNA into smaller molecules in the presence or absence of reverse transcriptase-associated endonuclease. However, in the presence of the enzyme the DNA is cleaved to a greater extent.
ABSTRACT
The cupric complex of isonicotinic acid hydrazide was found to be nontoxic to normal yolk sac macrophages upto a concentration of 100 μΜ. At this concentration the complex did not significantly inhibit DNA, RNA or protein synthesis in these cells. The complex inhibited the avian myeloblastosis virus multiplication in these cells when added 0–4 h post-infection as demonstrated by the inhibition of both focus formation and expression of viral specific antigens. This inhibition was not observed when the complex was added 8 and 16 h after avian myeloblastosis virus infection. The studies carried out on avian myeloblastosis virus-transformed myeloblasts indicated that the complex had no effect on the colony (focus) formation. The results suggest that the complex inhibits the virus multiplication by interfering in an early event of viral growth cycle, possibly the process of reverse transcription.