title: tDNA(ser) sequences are involved in the excision of Streptomyces griseus plasmid pSG1.
abstract: Plasmid pSG1 is maintained in some derivatives of Streptomyces griseus NRRL3851 mainly in the chromosomally integrated form (pSG1int). In others, the integrated plasmid is co-maintained with free pSG1 [Cohen et al., Plasmid 13 (1985) 41-50]. The pSG1 plasmid integration site (attP) and the pSG1int-chromosome boundaries (attL and attR) were cloned and sequenced. The results indicate that pSG1int is flanked at attL by a functional tRNA(ser) gene and at attR by a 60-nt sequence of the 3' end of the same tRNA(ser) gene. A single mismatch distinguishes the 60-nt sequence at attR from its direct repeat at attL. The attP site contains a single copy of the 60-nt repeat, identical to the one at attL. This observation indicates that pSG1, like integrating plasmids of other Actinomycetes, is integrated in a tRNA gene and suggests that the exact excision of pSG1int occurs by a recombinational crossing-over event at the first 43 nt of the 60-nt repeat.
authors.affiliation: Department of Molecular Genetics, Hadassah Medical School, Hebrew University, Jerusalem, Israel.
authors.forename: D
authors.initials: D
authors.lastname: Bar-Nir
authors.forename: A
authors.initials: A
authors.lastname: Cohen
authors.forename: M E
authors.initials: ME
authors.lastname: Goedeke
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002876:Chromosomes, Bacterial; D003001:Cloning, Molecular; D003434:Crossing Over, Genetic; D004269:DNA, Bacterial; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010957:Plasmids; D012362:RNA, Transfer, Ser / Q000737:chemistry / Q000235:genetics*; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D013305:Streptomyces griseus / Q000235:genetics*
chemical_list: D004269:DNA, Bacterial; D012362:RNA, Transfer, Ser