Evolutionary conservation and divergence of fungal promoter sequences.
Riccarda Rischatsch, Sylvia Voegeli, Peter Philippsen
Applied Microbiology, Biozentrum Basel, Klingelbergstr. 50, Basel, CH-4056, Switzerland
The sequenced and fully annotated genome of the filamentous fungus Ashbya gossypii reveals striking similarity to the baker`s yeast Saccharomyces cerevisiae. 90% of A. gossypii genes share homology and also a substantial degree of synteny (gene order conservation) with S. cerevisiae. Although both organisms originate from the same ancestor (carrying about 5000 protein coding genes), their modes of growth and their eclogical habitats differ significantly. The evaluation of synteny was complicated by the fact that the evolutionary paths of both genomes included not only about 300 translocations and inversions but also a whole genome duplication in the S. cerevisiae lineage followed by loss of 4000 genes. As a consequence the alignment of the A. gossypii genes with homologous S. cerevisiae genes results in many clusters of ancient synteny in which one A. gossypii chromosomal region aligns with two chromosomal regions of S. cerevisiae. We evaluated changes in promoters of syntenic regions defined by the synteny map. Despite a high size conservation of syntenic ORFs, sizes of promoter regions revealed striking differences. We analyzed in detail conservation of promoter elements in histone genes and of S. cerevisiae genes belonging to the network of mating and filamentation in comparison to their syntenic genes in A. gossypii.