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Heterogeneous genomic amplification in Streptomyces glaucescens: structure, location and junction sequence analysis
1Mikrobiologisches Institut, Eidgenössische Technische Hochschule, Zürich, Switzerland.
Molecular & General Genetics : MGG
|June 1, 1989
Summary
Genomic instability in Streptomyces glaucescens leads to DNA deletions and amplifications. This study characterized amplified DNA sequences (ADS) and amplifiable units of DNA (AUD), revealing their heterogeneous nature and origins.
Area of Science:
- Microbial genetics
- Molecular biology
- Genomics
Background:
- Streptomyces glaucescens exhibits chromosomal instability.
- Genomic deletions are frequently associated with DNA amplification in mutant strains.
Purpose of the Study:
- To investigate the structure of amplified DNA sequences (ADS).
- To characterize the corresponding wild-type amplifiable units of DNA (AUD).
- To understand the mechanisms behind heterogeneous DNA amplifications.
Main Methods:
- Utilized a wild-type cosmid library for investigation.
- Sequenced termini of four AUDs.
- Employed orthogonal-field-alternation gel electrophoresis (OFAGE) for visualization.
Main Results:
- Amplifications were heterogeneous in location, copy number, and sequences.
- Reiterations predominantly originated from a single 100 kb region, the AUD locus.
- Associated deletions were found in all reiterating strains, and tandem reiterations exceeded 1,500 kb.
Conclusions:
- Amplified DNA sequences in Streptomyces glaucescens arise from a specific chromosomal locus (AUD locus).
- The amplification process involves deletions and exhibits significant heterogeneity.
- Small, interrupted homologies may play a role in the formation of these amplifications.