Xin W N, Feiss M
Department of Microbiology, College of Medicine, University of Iowa, Iowa City 52242.
Nucleic Acids Res. 1988 Mar 25;16(5):2015-30. doi: 10.1093/nar/16.5.2015.
The interaction of E. coli integration host factor (IHF) with the cohesive end sites (cos's) of phages lambda and 21 has been studied by the DNAase I footprinting technique. Six potential sites in cos lambda differ from the consensus IHF binding sequence by 1 to 3 base pairs. Of the six, one site, I1, binds IHF strongly. The I1 segment protected by IHF contains two sequences that closely match the IHF consensus binding sequence. Another site, I2, binds IHF moderately well, and three sites: 10', 13 and 14 bind IHF very weakly. The 10 site does not bind IHF under the conditions used here. In phage 21 the DNA segment extending to the right from the cohesive ends, which contains three potential IHF binding sites, was examined. Two sites bind IHF well; I1, the 21 analogue of one of the lambda I1 sites, and I0, a site not analogous to a lambda site. The third 21 site, I2, binds IHF moderately well, as does the analogous I2 site in lambda. The significance of the results for lambda DNA packaging is discussed.
利用DNA酶I足迹技术研究了大肠杆菌整合宿主因子（IHF）与噬菌体λ和21的粘性末端位点（cos位点）之间的相互作用。cos λ中的六个潜在位点与IHF结合序列共有序列相差1至3个碱基对。其中，一个位点I1与IHF紧密结合。受IHF保护的I1片段包含两个与IHF共有结合序列紧密匹配的序列。另一个位点I2与IHF结合适中，还有三个位点10'、13和14与IHF结合非常弱。在本文所用条件下，10位点不与IHF结合。在噬菌体21中，研究了从粘性末端向右延伸的DNA片段，该片段包含三个潜在的IHF结合位点。两个位点与IHF结合良好；I1是λ I1位点之一的21类似物，I0是一个与λ位点不类似的位点。21的第三个位点I2与IHF结合适中，λ中的类似I2位点也是如此。讨论了这些结果对λ DNA包装的意义。
