Abstract:
:Renewed interest in gene amplification stems from its importance in evolution and a variety of medical problems ranging from drug resistance to cancer. However, amplified DNA segments (amplicons) are not fully characterized in any organism. Here we report a novel Acinetobacter baylyi system for genome-wide studies. Amplification mutants that consume aromatic compounds were selected under conditions requiring high-level expression from three promoters in a linked set of chromosomal genes. Tools were developed to relocate these catabolic genes to any non-essential chromosomal position, and 49 amplification mutants from five genomic contexts were characterized. Amplicon size (18-271 kb) and copy number (2-105) indicated that 30% of mutants carried more than 1 Mb of amplified DNA. Amplification features depended on genomic position. For example, amplicons from one locus were similarly sized but displayed variable copy number, whereas those from another locus were differently sized but had comparable copy number. Additionally, the importance of sequence context was highlighted in one region where amplicons differed depending on the presence of a promoter mutation in the strain from which they were selected. DNA sequences at amplicon boundaries in 19 mutants reflected illegitimate recombination. Furthermore, steady-state duplication frequencies measured under non-selective conditions (10(-4) to 10(-5) ) confirmed that spontaneous gene duplication is a major source of genetic variation.
journal_name
Mol Microbioljournal_title
Molecular microbiologyauthors
Seaton SC,Elliott KT,Cuff LE,Laniohan NS,Patel PR,Neidle ELdoi
10.1111/j.1365-2958.2011.07945.xsubject
Has Abstractpub_date
2012-02-01 00:00:00pages
520-35issue
3eissn
0950-382Xissn
1365-2958journal_volume
83pub_type
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