Streptomyces coelicolor A3(2) plasmid SCP2*: deductions from the complete sequence.
Plasmid SCP2* is a 31 kb, circular, low-copy-number plasmid originally identified in Streptomyces coelicolor A3(2) as a fertility factor. The plasmid was completely sequenced. The analysis of the 31 317 bp sequence revealed 34 ORFs encoding putative proteins from 31 to 710 aa long, most of them lacking similarity to known proteins. Three functional regions had been identified previously: the replication region, the transfer and spreading region, and the stability region. Three genes were identified in the stability region which contribute to the stability of SCP2 as shown by plasmid stability testing. The first gene, mrpA, encodes a new member of the lambda integrase family of site-specific recombinases. The two genes downstream of mrpA were called parA and parB. The gene product, ParA, shows similarity to a family of ATPases involved in plasmid partition. An increase of plasmid stability could be seen only when both genes were present. By deletion analysis, the replication region could be narrowed down to a 1.6 kb region, consisting of a 650 bp non-coding region and two genes, repI and repII, encoding proteins of 161 and 131 aa. Only RepI exhibits similarities to DNA binding elements and contains a putative helix-turn-helix motif. The traA gene that is essential for DNA transfer and pock formation was identified previously. Upstream of traA, 10 ORFs were found in the same orientation as traA which might be involved in conjugation and DNA spreading, together with one gene in the opposite orientation with similarities to transcriptional regulators of DNA transfer. Two transposable elements were found on SCP2*. IS1648 belongs to the IS3 family of insertion sequences. The second element, Tn5417, shows the highest similarity to the Tn4811 element located in the terminal inverted repeats of the Streptomyces lividans chromosome.
Haug
Iris
I
Institut für Industrielle Genetik, Universität Stuttgart, Allmandring 31, 70569 Stuttgart, Germany.
Weissenborn
Anke
A
Mikrobiologie/Biotechnologie, Eberhard-Karls-Unversität Tübingen, 72076 Tübingen, Germany.
Brolle
Dirk
D
Team Leader Marketing Urology, Pfizer GmbH, PO Box 4949, 76032 Karlsruhe, Germany.
Bentley
Stephen
S
The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK.
Kieser
Tobias
T
John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, UK.
Altenbuchner
Josef
J
Institut für Industrielle Genetik, Universität Stuttgart, Allmandring 31, 70569 Stuttgart, Germany.
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D003227:Conjugation, Genetic; D004261:DNA Replication; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000235:genetics; D004270:DNA, Circular / Q000235:genetics; D005822:Genetic Vectors; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D010957:Plasmids; D018741:Replication Origin; D015183:Restriction Mapping; D017422:Sequence Analysis, DNA; D013302:Streptomyces / Q000235:genetics / Q000254:growth & development
D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D004270:DNA, Circular