Autonomously Replicating Sequence of Linear Plasmid SLP2 of Streptomyces

• Main Authors: Ji-Rong Yang, 楊季融
• Other Authors: Carton W. Chen
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/89669001648967509911

碩士 === 國立陽明大學 === 遺傳學研究所 === 91 === SLP2 is a 50-kb linear plasmid present in low copy numbers in Streptomyces lividans, which promotes conjugation and transfer of plasmid and chromosome. Replication of SLP2 is supposedly, like other linear Streptomyces plasmids, initiated internally, and proceeds bidirectionally towards the ends. This work identified an autonomously replicating sequence (ARS) of 4703-bp (nt 4625-9328) on SLP2 DNA that includes a terminal protein gene tpgSLP2, a dnaB-like helicase gene and a 1.9-kb non-coding region containing a putative partitioning signal (parS). This ARS supports replication of mini-linear plasmids in S. lividans. In order to map the position of the replication origin within the 4.7-kb ARS, two-dimensional gel electrophoresis was used to analyze replication intermediates of mini-linear DNA pLUS349 that contains this ARS. The results indicated that replication origin of the ARS is located near nt 7640 of SLP2 DNA that lies in a non-coding region upstream of the dnaB-like helicase with a relatively low G+C content.