RESUMO
We have sequenced and annotated the genome of the filamentous ascomycete Ashbya gossypii. With a size of only 9.2 megabases, encoding 4718 protein-coding genes, it is the smallest genome of a free-living eukaryote yet characterized. More than 90% of A. gossypii genes show both homology and a particular pattern of synteny with Saccharomyces cerevisiae. Analysis of this pattern revealed 300 inversions and translocations that have occurred since divergence of these two species. It also provided compelling evidence that the evolution of S. cerevisiae included a whole genome duplication or fusion of two related species and showed, through inferred ancient gene orders, which of the duplicated genes lost one copy and which retained both copies.
Assuntos
Mapeamento Cromossômico , Genoma Fúngico , Saccharomyces cerevisiae/genética , Saccharomycetales/genética , Análise de Sequência de DNA , Composição de Bases , Evolução Biológica , Centrômero/genética , Inversão Cromossômica , Biologia Computacional , Proteínas Fúngicas/genética , Duplicação Gênica , Ordem dos Genes , Genes Fúngicos , Dados de Sequência Molecular , Fases de Leitura Aberta , Alinhamento de Sequência , Homologia de Sequência do Ácido Nucleico , Sintenia , Translocação GenéticaRESUMO
2-Hexyl-5-propylresorcinol is the predominant analog of several dialkylresorcinols produced by Pseudomonas aurantiaca (Pseudomonas fluorescens BL915). We isolated and characterized three biosynthetic genes that encode an acyl carrier protein, a beta-ketoacyl-acyl carrier protein synthase III, and a protein of unknown function, all of which collectively allow heterologous production of 2-hexyl-5-propylresorcinol in Escherichia coli. Two regulatory genes exhibiting similarity to members of the AraC family of transcriptional regulators are also present in the identified gene cluster. Based on the deduced functions of the proteins encoded by the gene cluster and the observed incorporation of labeled carbons from octanoic acid into 2-hexyl-5-propylresorcinol, we propose that dialkylresorcinols are derived from medium-chain-length fatty acids by an unusual head-to-head condensation of beta-ketoacyl thioester intermediates. Genomic evidence suggests that there is a similar pathway for the biosynthesis of the flexirubin-type pigments in certain bacteria belonging to the order Cytophagales.
