Replication-biased genome organisation in the crenarchaeon Sulfolobus
1 Department of Ecology and Evolution, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
2 Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, Sweden
3 Department of Molecular Evolution, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
4 Department of Cell and Molecular Biology, Biomedical Centre, Uppsala University, Uppsala, Sweden
5 Department of Proteomics, School of Biotechnology, KTH Royal Institute of Technology, Albanova University Centre, Stockholm, Sweden
BMC Genomics 2010, 11:454 doi:10.1186/1471-2164-11-454Published: 28 July 2010
Species of the crenarchaeon Sulfolobus harbour three replication origins in their single circular chromosome that are synchronously initiated during replication.
We demonstrate that global gene expression in two Sulfolobus species is highly biased, such that early replicating genome regions are more highly expressed at all three origins. The bias by far exceeds what would be anticipated by gene dosage effects alone. In addition, early replicating regions are denser in archaeal core genes (enriched in essential functions), display lower intergenic distances, and are devoid of mobile genetic elements.
The strong replication-biased structuring of the Sulfolobus chromosome implies that the multiple replication origins serve purposes other than simply shortening the time required for replication. The higher-level chromosomal organisation could be of importance for minimizing the impact of DNA damage, and may also be linked to transcriptional regulation.