Diversity of telomere palindromic sequences and replication genes among Streptomyces linear plasmids.
Streptomyces sp. linear plasmids and linear chromosomes usually contain conserved terminal palindromic sequences bound by the conserved telomeric proteins Tap and Tp, encoded by the tap and tpg genes, respectively, as well as plasmid loci required for DNA replication in circular mode when the telomeres are deleted. These consist of iterons and an adjacent rep gene. By using PCR, we found that 8 of 17 newly detected linear plasmids in Streptomyces strains lack typical telomeric tap and tpg sequences. Instead, two novel telomeres in plasmids pRL1 and pRL2 from the eight strains and one conserved telomere in pFRL1 from the other strains were identified, while multiple short palindromes were also found in the plasmids. The complete nucleotide sequence of pRL2 revealed a gene encoding a protein containing two domains, resembling Tap of Streptomyces and a helicase of Thiobacillus, and an adjacent gene encoding a protein similar to Tpg of Streptomyces and a portion of the telomere terminal protein pTP of adenoviruses. No typical iterons-rep loci were found in the three plasmids. These results indicate an unexpected diversity of telomere palindromic sequences and replication genes among Streptomyces linear plasmids.
Zhang
Ran
R
Shanghai Institute of Plant Physiology, Shanghai Institutes of Biological Science, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, People's Republic of China.
Yang
Yong
Y
Fang
Ping
P
Jiang
Chenglin
C
Xu
Lihua
L
Zhu
Yingmin
Y
Shen
Meijuan
M
Xia
Haiyang
H
Zhao
Jianfu
J
Chen
Tongbin
T
Qin
Zhongjun
Z
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D003001:Cloning, Molecular; D004261:DNA Replication / Q000235:genetics; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005798:Genes, Bacterial; D014644:Genetic Variation; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010957:Plasmids / Q000235:genetics* / Q000302:isolation & purification; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013302:Streptomyces / Q000235:genetics* / Q000302:isolation & purification; D016615:Telomere / Q000235:genetics*
D001426:Bacterial Proteins; D004269:DNA, Bacterial