The UV induced pili system and DNA transfer
Almost all Sulfolobales contain an type IV pili operon named the UV inducible pilus operon (ups). This operon is highly induced after UV treatment of Sulfolobus cells or the occurence of DNA double strand breakages. As a result the cells express multiple pili all around the cell surface and start to aggregate (see image). In these aggregates the cells exchange DNA which is subsequently used to repair their genomic DNA by homologous recombination. Recently, we have have identi