Prioritizing orphan proteins for further study using phylogenomics and gene expression profiles in <it>Streptomyces coelicolor</it>

Abstract

Abstract Background Streptomyces coelicolor, a model organism of antibiotic producing bacteria, has one of the largest genomes of the bacterial kingdom, including 7825 predicted protein coding genes. A large number of these genes, nearly 34%, are functionally orphan (hypothetical proteins with unknown function). However, in gene expression time course data, many of these functionally orphan genes show interesting expression patterns. Results In this paper, we analyzed all functionally orphan genes of Streptomyces coelicolor and identified a list of "high priority" orphans by combining gene expression analysis and additional phylogenetic information (i.e. the level of evolutionary conservation of each protein). Conclusions The prioritized orphan genes are promising candidates to be examined experimentally in the lab for further characterization of their function.