Assembly and function of pili in gene transfer and biofilm formation in Sulfolobus solfataricus
01 / 2009 - 12 / 2012
Archaea constitute the third domain of life and are believed to be close to the origin of life. They comprise a diverse group of micro-organisms that combine bacterial and eukaryotic features but also employ many novel mechanisms. They posses a unique cell envelope with a cytoplasmic membrane of ether lipids surrounded by a proteinaceous S-layer and various cell appendages such as flagella, pili and other, unusual structures. We identified a UV stress induced system that assembles pili in the cell envelope of the hyperthermoacidophilic archaeon Sulfolobus solfataricus. This system involves two sets of genes that encode the pilus assembly machinery and the proteins involved in DNA modification and transfer, respectively. Therefore, we hypothesize that this system constitutes an archaeal DNA transfer system ensuring genome integrity after e.g. UV stress but possibly also in natural ecosystems. The UV-induced system appears of a lesser complexity that its bacterial counterparts, involving only 2-4 subunits for pilus assembly. Possibly the archaeal system represents a primordial form of a bacterial assembly and DNA transfer machinery. Moreover, it might be important for not only intra-species, but also interspecies DNA transfer in microbial communities leading to an increased biodiversity in these habitats. In this project will employ biochemical and genetic methods to elucidate the mechanism of pilus assembly and DNA transfer in S. solfataricus and access its role in biofilm formation, cell-to-cell contact and conjugation.