Genome-wide transcription map of an archaeal cell cycle

Abstract

Relative RNA abundance was measured at different cell-cycle stages in synchronized cultures of the hyperthermophilic archaeon Sulfolobus acidocaldarius. Cyclic induction was observed for >160 genes, demonstrating central roles for transcriptional regulation and cell-cycle-specific gene expression in archaeal cell-cycle progression. Many replication genes were induced in a cell-cyclespecific manner, and novel replisome components are likely to be among the genes of unknown function with similar induction patterns. Candidate genes for the unknown genome segregation and cell division machineries were also identified, as well as seven transcription factors likely to be involved in cell-cycle control. Two serine-threonine protein kinases showed distinct cell-cycle-specific induction, suggesting regulation of the archaeal cell cycle also through protein modification. Two candidate recognition elements, CCR boxes, for transcription factors in control of cell-cycle regulons were identified among gene sets with similar induction kinetics. The results allow detailed characterization of the genome segregation, division, and replication processes and may, because of the extensive homologies between the archaeal and eukaryotic information machineries, also be applicable to core features of the eukaryotic cell cycle.Archaea ͉ chromosome replication ͉ microarrays ͉ mitosis ͉ Sulfolobus

Chromosome replication dynamics in the archaeon Sulfolobus acidocaldarius

“…Several laboratories have reported microarray analyses of the response of the Sulfolobus transcriptome to a range of physiological stresses such as UV treatment, viral infection, and heat shock (21)(22)(23)(24). Interestingly, these studies have revealed modulation of Orc1 gene transcript and/or protein levels; similar to that seen with microarray analysis of acetate-treated cells (25). It seems likely, therefore, that the modulation of Orc1/Cdc6 levels induced by acetate treatment and subsequent resumption of growth reflects a stress response in Sulfolobus cells rather than a true cell cycle effect.…”

Transcriptome Analysis of Infection of the Archaeon Sulfolobus solfataricus with Sulfolobus Turreted Icosahedral Virus

“…Sequences in the S. solfataricus genome in which these proteins bind to initiate chromosome replication have been identified (24); however, a search of the STIV genome did not reveal similar sequences. Recent analysis of the cell cycle in synchronized cultures of Sulfolobus acidocaldarius, a close relative of S. solfataricus, suggested that these two genes are up-regulated as the cell enters the growth phase in which the chromosome is replicated (16). The cell cycle of Sulfolobus spp.…”

“…Of particular interest is the detection of two of the three cdc6-like genes, cdc6-1 (SSO0257) and cdc6-3 (SSO2184), which are associated with the three origins of replication in S. solfataricus (15). These two genes are closely associated with replication origins, while the other gene, cdc6-2 (SSO0771), is offset from the third origin of replication, and its product may be functionally distinct from those of the other two cdc6 genes (16). During the time course, cdc6-2 (SSO0771) was expressed at the same level in both infected and control cultures.…”

Chromosome segregation in Archaea mediated by a hybrid DNA partition machine

“…The 3′ end of S. solfataricus segA overlaps with the 5′ end of segB: this arrangement suggests that the genes may be part of a single transcriptional unit implying that SegA and SegB are involved in the same biological process. Supporting evidence derives from a transcription profiling study showing that the S. acidocaldarius homologs of segA and segB (Saci_0204 and Saci_0203, respectively) are coordinately expressed in a cell cycle-regulated fashion (19).…”