Banuett F, Hoyt M A, McFarlane L, Echols H, Herskowitz I
J Mol Biol. 1986 Jan 20;187(2):213-24. doi: 10.1016/0022-2836(86)90229-9.
The level of the viral cII protein has been proposed to be the crucial determinant in the lysis-lysogeny decision of bacteriophage lambda. A new Escherichia coli locus (hflB) has been identified in which a mutation (hflB29) leads to high frequency of lysogeny by lambda. A double mutant defective in both hflB and the previously identified hflA gene displays a more severe Hfl- phenotype than either single mutant. The hflB locus is at 69 minutes on the E. coli map, 85% co-transducible with argG. The hflB29 mutation results in increased stability of the phage cII protein (increasing its half-life twofold) and is recessive to hflB+. We conclude that the hflB+ locus is a negative regulator of cII, perhaps coding for or regulating a protease that acts on cII. In addition, we observe that the can1 mutation, an alteration of the cII gene that results in enhanced lysogenization, leads to increased stability of cII protein. These observations reinforce the view that the level of cII is a key factor in the lysis-lysogeny decision of lambda.
病毒cII蛋白的水平被认为是噬菌体λ裂解-溶原化决定中的关键决定因素。已鉴定出一个新的大肠杆菌基因座（hflB），其中的一个突变（hflB29）导致λ噬菌体溶原化的高频发生。hflB和先前鉴定的hflA基因均有缺陷的双突变体表现出比任一单突变体更严重的Hfl-表型。hflB基因座在大肠杆菌染色体图谱上位于69分钟处，与argG的共转导率为85%。hflB29突变导致噬菌体cII蛋白的稳定性增加（其半衰期增加两倍），并且对hflB+呈隐性。我们得出结论，hflB+基因座是cII的负调节因子，可能编码或调节作用于cII的一种蛋白酶。此外，我们观察到can1突变，即cII基因的一种改变，导致溶原化增强，会使cII蛋白的稳定性增加。这些观察结果强化了这样一种观点，即cII的水平是λ噬菌体裂解-溶原化决定中的一个关键因素。
