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- Pelve, Erik A., 1980-, et al.
(författare)
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Cdv-based cell division and cell cycle organization in the thaumarchaeon Nitrosopumilus maritimus
- 2011
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Ingår i: Molecular Microbiology. - : Wiley. - 0950-382X .- 1365-2958. ; 82:3, s. 555-566
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Tidskriftsartikel (refereegranskat)abstract
- Cell division is mediated by different mechanisms in different evolutionary lineages. While bacteria and euryarchaea utilize an FtsZ-based mechanism, most crenarchaea divide using the Cdv system, related to the eukaryotic ESCRT-III machinery. Intriguingly, thaumarchaeal genomes encode both FtsZ and Cdv protein homologues, raising the question of their division mode. Here, we provide evidence indicating that Cdv is the primary division system in the thaumarchaeon Nitrosopumilus maritimus. We also show that the cell cycle is differently organized as compared to hyperthermophilic crenarchaea, with a longer pre-replication phase and a shorter post-replication stage. In particular, the time required for chromosome replication is remarkably extensive, 15-18 h, indicating a low replication rate. Further, replication did not continue to termination in a significant fraction of N. maritimus cell populations following substrate depletion. Both the low replication speed and the propensity for replication arrest are likely to represent adaptations to extremely oligotrophic environments. The results demonstrate that thaumarchaea, crenarchaea and euryarchaea display differences not only regarding phylogenetic affiliations and gene content, but also in fundamental cellular and physiological characteristics. The findings also have implications for evolutionary issues concerning the last archaeal common ancestor and the relationship between archaea and eukaryotes.
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| 2. |
- Pelve, Erik A., et al.
(författare)
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Mapping of active replication origins in vivo in thaum- and euryarchaeal replicons
- 2013
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Ingår i: Molecular Microbiology. - : Wiley. - 0950-382X .- 1365-2958. ; 90:3, s. 538-550
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Tidskriftsartikel (refereegranskat)abstract
- We report mapping of active replication origins in thaum- and euryarchaeal replicons using high-throughput sequencing-based marker frequency analysis. The chromosome of the thaumarchaeon Nitrosopumilus maritimus is shown to contain a single origin of replication, whereas the main chromosome in the halophilic euryarchaea Haloferax mediterranei and Haloferax volcanii each contains two origins. All replication origins specified bidirectional replication, and the two origins in the halophiles were initiated in synchrony. The pHM500 plasmid of H.mediterranei is shown to contain a single origin, and the copy numbers of five plasmid replicons in the two halophiles were inferred to be close to that of the main chromosome. Origin recognition boxes (ORBs) that provide binding sites for Orc1/Cdc6 replication initiator proteins are identified at all chromosomal origins, as well as in a range of additional thaumarchaeal species. An annotation update is provided for all three species.
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