Cordycepin reduces the sensitivity of BALB/Mo mouse lymphocytes to the induction of sister chromatid exchanges.

Lymphocytes from the spleen of BALB/Mo mice, which carry endogenous Moloney murine leukemia virus (M-MuLV), show in vitro frequencies of sister chromatid exchanges (SCEs) significantly higher than lymphocytes from control (M-MuLV free) BALB/c mice. In vitro treatment of lymphocytes with the antiviral antibiotic cordycepin (10 micrograms/ml) lowers the level of SCEs in BALB/Mo cells to the same value of BALB/c cells. M-MuLV yield is also markedly reduced in BALB/Mo lymphocytes cultured in the presence of cordycepin. The drug also abolishes the increased sensitivity of BALB/Mo lymphocytes to the induction of SCEs by mitomycin C (MMC) either in vitro (3 X 10(-8)/10(-7)M) or in vivo (0.3/3 mg/kg). Since cordycepin is known to inhibit poly(A)synthesis thus blocking RNA maturation, it is suggested that M-MuLV proviral integration is not per se the sole factor responsible for the more pronounced susceptibility of BALB/Mo lymphocytes to SCE induction, but most likely viral gene expression and amplification are needed for this effect to occur.