A REPETITIVE DNA-SEQUENCE, RHS, RESPONSIBLE FOR DUPLICATIONS WITHIN THE ESCHERICHIA-COLI K-12 CHROMOSOME
A REPETITIVE DNA-SEQUENCE, RHS, RESPONSIBLE FOR DUPLICATIONS WITHIN THE ESCHERICHIA-COLI K-12 CHROMOSOME
复制标题
DOI：
10.1016/0022-2836(84)90054-8
复制
发表时间：
1984-01-01
影响因子：
5.6
通讯作者：
HILL, CW
中科院分区：
文献类型：
--
作者：
LIN, RJ;CAPAGE, M;HILL, CW
在大肠杆菌中发现了一个新的大的、不完全重复的DNA序列家族。杆菌该家族的两个成员rhsA和rhsB作为直接重复序列出现，位于染色体的pit glyS xyl片段的侧翼。rhsA和rhsB之间的不相等的姐妹染色单体交换解释了各种工作者已经观察到的glyS位点的频繁串联重复。这种不等重组是recA依赖的。rhsA基因座在操作上定义为在其他染色体位置重复的xyl和mtl之间的区段。根据这个定义，rhsA至少延伸5500个碱基对; rhsA的3800个碱基对与rhsB足够同源，以与其形成S1核酸酶抗性异源双链体。在E.大肠杆菌染色体未与rhsA或rhsB连锁。对大肠杆菌基因组DNA进行限制性内切酶Southern分析。大肠杆菌菌株C和B/5的rhs杂交图谱与菌株K-12相似，但鼠伤寒沙门氏菌中没有rhs序列。rhs序列的功能尚未被发现。在这项工作的过程中，开发了一种称为转导步移的技术，通过该技术，可以通过遗传程序克隆与先前克隆的DNA片段相邻的染色体DNA。
A novel family of large, imperfectly repeated DNA sequences ws found in E. coli. Two members of this family, rhsA and rhsB, occur as direct repeats, flanking the pit glyS xyl segment of the chromosome. Unequal sister-chromatid crossing over between rhsA and rhsB accounts for the frequent tandem duplication of the glyS locus that has been observed by various workers. This unequal recombination is recA-dependent. The rhsA locus is operationally defined as the segment between xyl and mtl that is repeated at other chromosomal locations. Using this definition, rhsA extends minimally 5500 base-pairs; 3800 base-pairs of rhsA are sufficiently homologous to rhsB to form an S1 nuclease-resistant heteroduplex with it. The rhsA sequence also exhibits internal repetition. At least 1 additional rhs sequence occurs in the E. coli chromosome unlinked to either rhsA or rhsB. Southern analysis of restriction digests of genomic DNA from E. coli strains C and B/5 showed that both of these strains have rhs hybridizable patterns similar to strain K-12, but the rhs sequence is absent in Salmonella typhimurium. The function of the rhs sequences has not been discovered. In the course of this work was a technique was developed, termed transductional walking, by which chromosomal DNA adjacent to a previously cloned DNA segment can be cloned through genetic procedures.