McAllister W T, Green D M
J Virol. 1973 Aug;12(2):300-9. doi: 10.1128/JVI.12.2.300-309.1973.
The last genetic markers to be transferred during bacteriophage SP82G infection have a higher sensitivity to the decay of incorporated radioactive phosphorous ((32)P) than those which are located on the proximal end of the genome. If (32)P decay is permitted to take place after DNA transfer is complete (in frozen infective centers) and in the absence of DNA replication, no dependence of marker sensitivity on map position is observed. These results indicate that the decay of incorporated (32)P leads to damages that prevent the efficient transfer of portions of the genome distal to the lesion. At 4 C, failure to transfer some portion of the genome occurs in 49% of all lethal events. Even though damages that prevent transfer of the genome are in themselves lethal, they do not prevent rescue of genetic markers on portions of the genome that are transferred. The portion of the genome that is transferred, is transferred at the same rate as an undamaged genome. We interpret these results to mean that double-strand breaks in the DNA are the lesions that prevent distal transfer and that single-strand breaks have little or no effect on the transfer of the bacteriophage SP82G genome.
在噬菌体SP82G感染过程中最后转移的遗传标记，比位于基因组近端的那些标记对掺入的放射性磷（³²P）衰变具有更高的敏感性。如果在DNA转移完成后（在冷冻感染中心）且不存在DNA复制的情况下允许³²P衰变，则未观察到标记敏感性对图谱位置的依赖性。这些结果表明，掺入的³²P衰变会导致损伤，从而阻止基因组损伤部位远端部分的有效转移。在4℃时，所有致死事件中有49%发生未能转移基因组某些部分的情况。尽管阻止基因组转移的损伤本身是致死性的，但它们并不妨碍对已转移基因组部分上的遗传标记进行拯救。基因组中被转移的部分，其转移速率与未受损基因组相同。我们将这些结果解释为，DNA中的双链断裂是阻止远端转移的损伤，而单链断裂对噬菌体SP82G基因组的转移几乎没有影响。
