Hanks M C, Newman B, Oliver I R, Masters M
Department of Molecular Biology, King's Buildings, Edinburgh, Scotland.
Mol Gen Genet. 1988 Nov;214(3):523-32. doi: 10.1007/BF00330490.
P1 transduces bacterial chromosomal markers with widely differing frequencies. We use quantitative Southern hybridisations here to show that, despite this, most markers are packaged at similar levels. Exceptions are a group of markers near 2 min and another at 90 min which seem to be packaged at levels two- to threefold higher. We thus conclude that certain marker frequency variations in transduction can be explained by differences in packaging level, but that most cannot. The limited range in packaging levels suggests that P1 can initiate the packaging of chromosomal DNA from many sites. This idea is supported by our failure to find any chromosomal sequences with homology to the phage pac site and by the occurrence of hybridising bands which seem to suggest sequential packaging from a large number of specific sites. We eliminate the possibility that chromosomal DNA packaging is the result of endonucleolytic cutting by the P1 res enzyme.
P1以差异很大的频率转导细菌染色体标记。我们在此使用定量Southern杂交来表明，尽管如此，大多数标记的包装水平相似。例外情况是一组位于2分钟附近的标记和另一组位于90分钟的标记，它们的包装水平似乎高出两到三倍。因此，我们得出结论，转导中某些标记频率的变化可以用包装水平的差异来解释，但大多数情况并非如此。包装水平的有限范围表明P1可以从许多位点启动染色体DNA的包装。我们未能找到与噬菌体pac位点具有同源性的任何染色体序列，以及出现似乎表明从大量特定位点进行连续包装的杂交带，这些都支持了这一观点。我们排除了染色体DNA包装是由P1 res酶进行内切核酸切割的结果这种可能性。
