Miller G, Feiss M
Department of Microbiology, College of Medicine, University of Iowa, Iowa City 52242.
Mol Gen Genet. 1988 Apr;212(1):157-65. doi: 10.1007/BF00322459.
Substitution, insertion and deletion mutations have been constructed at the XmnI restriction site in cos lambda. The XmnI site is located between cosB, the site where terminase binds lambda DNA; and cosN, the site where terminase introduces staggered nicks to generate cohesive ends. Substitution mutations and deletion of a base pair (a -1 change) do not obviously affect lambda growth and DNA packaging. Changes of -2, +2 and -3 render lambda unable to grow on host cells lacking integration host factor (IHF). The -3 mutant has a reduced burst size in IHF+ cells, due to a defect in the initiation of packaging. A -7 deletion mutation is lethal. Models for the basis of these mutational effects are discussed.
已在λ噬菌体的XmnI限制性位点构建了替换、插入和缺失突变。XmnI位点位于cosB（末端酶结合λDNA的位点）和cosN（末端酶引入交错切口以产生粘性末端的位点）之间。替换突变和一个碱基对的缺失（-1变化）不会明显影响λ噬菌体的生长和DNA包装。-2、+2和-3的变化使λ噬菌体在缺乏整合宿主因子（IHF）的宿主细胞上无法生长。-3突变体在IHF+细胞中的爆发量减少，这是由于包装起始存在缺陷。-7缺失突变是致死的。文中讨论了这些突变效应的基础模型。
