Kholodii G Y, Mindlin S Z
Mol Gen Genet. 1984;197(1):104-8. doi: 10.1007/BF00327929.
The family of lambdoid phages displays a varying specificity of integration into the host chromosome. The lambda phage DNA failed to get inserted at the secondary site(s) of the gal operon (frequency less than 2.6 X 10(-8) in the presence of the primary (normal) att site. By contrast, phi 80 and the lambda att80 hybrid (lambda X phi 80) became integrated into wild-type Escherichia coli at at least two secondary att sites of the btuB locus, and the latter near purE and purC as well (frequency 2 X 10(-3)-10(-4). The integration of phi 80 and lambda att80 into btuB occurred with about the same frequency as in cells in which the normal insertion site had been deleted (0.7-4.0 X 10(-6). An analysis of the secondary lysogens with the prophage in btuB showed them to be polylysogens; the additional prophage(s) was found at the primary att site. We also failed to observe the integration into other loci of phi 80 and lambda att80 with the formation of secondary monolysogens (frequency less than 0.0035 at MOI = 10(-3) or 10). It is presumed that these prophages become integrated at secondary att sites only if the primary site is occupied.
λ样噬菌体家族在整合到宿主染色体上时表现出不同的特异性。λ噬菌体DNA在gal操纵子的二级位点未能插入（在存在主要（正常）att位点的情况下，频率低于2.6×10^(-8)）。相比之下，φ80和λatt80杂种（λ×φ80）在btuB位点的至少两个二级att位点整合到野生型大肠杆菌中，后者还靠近purE和purC（频率为2×10^(-3)-10^(-4)）。φ80和λatt80整合到btuB中的频率与正常插入位点已被删除的细胞中的频率大致相同（0.7-4.0×10^(-6)）。对btuB中有原噬菌体的二级溶源菌进行分析表明它们是多溶源菌；额外的原噬菌体存在于主要att位点。我们也未观察到φ80和λatt80整合到其他位点并形成二级单溶源菌（在感染复数为10^(-3)或10时，频率低于0.0035）。据推测，只有在主要位点被占据时，这些原噬菌体才会在二级att位点整合。
