%0 Journal Article
%T Comparative genomic hybridizations reveal absence of large Streptomyces coelicolor genomic islands in Streptomyces lividans
%A Karthik P Jayapal
%A Wei Lian
%A Frank Glod
%A David H Sherman
%A Wei-Shou Hu
%J BMC Genomics
%D 2007
%I BioMed Central
%R 10.1186/1471-2164-8-229
%X We identified five large S. coelicolor genomic islands (larger than 25 kb) and 18 smaller islets absent in S. lividans chromosome. Many of these regions show anomalous GC bias and codon usage patterns. Six of them are in close vicinity of tRNA genes while nine are flanked with near perfect repeat sequences indicating that these are probable recent evolutionary acquisitions into S. coelicolor. Embedded within these segments are at least four DNA methylases and two probable methyl-sensing restriction endonucleases. Comparison with S. coelicolor transcriptome and proteome data revealed that some of the missing genes are active during the course of growth and differentiation in S. coelicolor. In particular, a pair of methylmalonyl CoA mutase (mcm) genes involved in polyketide precursor biosynthesis, an acyl-CoA dehydrogenase implicated in timing of actinorhodin synthesis and bldB, a developmentally significant regulator whose mutation causes complete abrogation of antibiotic synthesis belong to this category.Our findings provide tangible hints for elucidating the genetic basis of important phenotypic differences between these two streptomycetes. Importantly, absence of certain genes in S. lividans identified here could potentially explain the relative ease of DNA transformations and the conditional lack of actinorhodin synthesis in S. lividans.Streptomyces spp. include some of the world's most prolific producers of naturally occurring bioactive molecules, many of which are in current therapeutic use [1]. These soil-dwelling filamentous bacteria exhibit a remarkably complex life style. Emerging from uni-genomic spores, they colonize the nutrient layer and eventually surface as multi-genomic aerial hyphae, often synthesizing secondary metabolites in the process. The extraordinary diversity of secondary metabolite gene clusters found in these microbes is likely the result of their existence in hostile ecological niches and consequent genomic evolutionary processes includin
%U http://www.biomedcentral.com/1471-2164/8/229