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Occurrence of deletions, associated with genetic instability in Streptomyces ambofaciens, is independent of the linearity of the chromosomal DNA.

TitleOccurrence of deletions, associated with genetic instability in Streptomyces ambofaciens, is independent of the linearity of the chromosomal DNA.
Publication TypeJournal Article
Year of Publication1997
AuthorsFischer, G, Decaris, B, Leblond, P
JournalJ Bacteriol
Volume179
Issue14
Pagination4553-8
Date Published1997 Jul
ISSN0021-9193
KeywordsBacterial Proteins, Chromosomes, Bacterial, DNA Probes, DNA, Bacterial, DNA, Circular, Electrophoresis, Gel, Pulsed-Field, Nucleic Acid Conformation, Repetitive Sequences, Nucleic Acid, Sequence Deletion, Streptomyces
Abstract

The chromosomal structures of mutant strains of Streptomyces ambofaciens which have arisen from genetic instability were investigated by using pulsed-field gel electrophoresis and probing with sequences cloned from the unstable region which maps near the ends of the linear chromosomal DNA. The chromosomal structures of seven mutant strains harboring large deletions were classified into three types. (i) Deletions internal to one chromosomal arm were characterized in two of the mutant strains. In these strains, a linear chromosomal structure was retained, as were parts of the terminal inverted repeats sequences (TIRs) and the proteins bound to them. (ii) Four of the mutants presented a deletion including all sequences from the TIRs. A junction fragment homologous to sequences originating from internal region of both arms was characterized. Consequently, the chromosomal DNA of these strains was deduced to be circularized. Furthermore, chromosomal stability was assessed in the progeny of these circular DNA mutants. Additional deletion events were detected in 11 mutants among the 13 strains isolated, demonstrating that circular chromosomes do not correspond to a stabilization of the chromosome structure and that the occurrence of deletion could be independent of the presence of chromosomal ends. (iii) A mutant with DNA amplification was shown to have a linear chromosome with a deletion of all sequences between the amplified region and the end of the chromosome. The other chromosomal arm remained unaffected by deletion and associated with protein.

Alternate JournalJ. Bacteriol.
PubMed ID9226265
PubMed Central IDPMC179291