Majone F, Montaldi A, Saggioro D, Brunetti R, Chieco-Bianchi L, Levis A G
Department of Biology, University of Padua, Italy.
Mutagenesis. 1987 Jul;2(4):259-62. doi: 10.1093/mutage/2.4.259.
BALB/Mo mice lymphocytes, carrying endogenous Moloney murine leukaemia virus (M-MuLV), show significantly higher in vitro baseline frequencies of sister chromatid exchange (SCE) than lymphocytes from control (M-MuLV free) BALB/c mice. In vitro treatment of lymphocytes with cordycepin (10 micrograms/ml), an antiviral substance, lowers the level of SCE in BALB/Mo cells to the same value of BALB/c cells. The drug also reduces the higher sensitivity of BALB/Mo compared to BALB/c lymphocytes to the induction of SCE by mitomycin C (MMC) administered either in vitro (3 x 10(-8), 10(-7) M) or in vivo (0.3, 3 mg/kg). BALB/Mo lymphocytes treated in vivo with a high dose of MMC (10 mg/kg) show reduced susceptibility to the induction of SCE but increased frequencies of chromatid breaks and micronuclei. In this situation, cordycepin increases the level of SCE in BALB/Mo lymphocytes to exactly the level seen in BALB/c cells, but it does not affect the frequency of chromosomal aberrations. Since cordycepin is known to inhibit poly(A) synthesis, thus blocking RNA maturation, it is suggested that M-MuLV proviral integration is not the sole factor responsible for the altered susceptibility of BALB/Mo lymphocytes to SCE induction, but that it is most likely viral gene expression that is needed for this effect to occur. On the contrary, the high susceptibility of BALB/Mo lymphocytes to the induction of chromatid aberrations by a high dose of MMC administered in vivo seems to be independent of viral maturation.
携带内源性莫洛尼鼠白血病病毒（M-MuLV）的BALB/Mo小鼠淋巴细胞，其体外姐妹染色单体交换（SCE）的基线频率显著高于对照（无M-MuLV）的BALB/c小鼠的淋巴细胞。用抗病毒物质虫草素（10微克/毫升）对淋巴细胞进行体外处理，可使BALB/Mo细胞中的SCE水平降低至与BALB/c细胞相同的值。该药物还降低了BALB/Mo淋巴细胞相较于BALB/c淋巴细胞对体外（3×10⁻⁸、10⁻⁷M）或体内（0.3、3毫克/千克）施用的丝裂霉素C（MMC）诱导SCE的更高敏感性。体内用高剂量MMC（10毫克/千克）处理的BALB/Mo淋巴细胞对SCE诱导的敏感性降低，但染色单体断裂和微核频率增加。在这种情况下，虫草素可将BALB/Mo淋巴细胞中的SCE水平提高至与BALB/c细胞中完全相同的水平，但不影响染色体畸变频率。由于已知虫草素可抑制多聚腺苷酸（poly(A)）合成，从而阻断RNA成熟，因此有人提出，M-MuLV前病毒整合并非BALB/Mo淋巴细胞对SCE诱导敏感性改变的唯一因素，而这种效应的发生很可能需要病毒基因表达。相反，BALB/Mo淋巴细胞对体内施用高剂量MMC诱导染色单体畸变的高敏感性似乎与病毒成熟无关。
