Abstract
Agrobacterium tumefaciens C58 contains four replicons, circular chromosome (CC), linear chromosome (LC), cryptic plasmid (pAt), and tumor-inducing plasmid (pTi), and grows by polar growth from a single growth pole (GP), while the old cell compartment and its old pole (OP) do not elongate. We monitored the replication and segregation of these four genetic elements during polar growth. The three largest replicons (CC, LC, pAt) reside in the OP compartment prior to replication; post replication one copy migrates to the GP prior to division. CC resides at a fixed location at the OP and replicates first. LC does not stay fixed at the OP once the cell cycle begins and replicates from varied locations 20 min later than CC. pAt localizes similarly to LC prior to replication, but replicates before the LC and after the CC. pTi does not have a fixed location, and post replication it segregates randomly throughout old and new cell compartments, while undergoing one to three rounds of replication during a single cell cycle. Segregation of the CC and LC is dependent on the GP and OP identity factors PopZ and PodJ, respectively. Without PopZ, replicated CC and LC do not efficiently partition, resulting in sibling cells without CC or LC. Without PodJ, the CC and LC exhibit abnormal localization to the GP at the beginning of the cell cycle and replicate from this position. These data reveal PodJ plays an essential role in CC and LC tethering to the OP during early stages of polar growth.
Original language | English |
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Pages (from-to) | 26366-26373 |
Number of pages | 8 |
Journal | Proceedings of the National Academy of Sciences of the United States of America |
Volume | 117 |
Issue number | 42 |
DOIs | |
Publication status | Published - 20 Oct 2020 |
Funding
ACKNOWLEDGMENTS. We thank Steven Ruzin, Ph.D., and Denise Schichnes, Ph.D., at the College of Natural Resources Biological Imaging Facility at University of California, Berkeley, for assistance with fluorescent imaging. The Biological Imaging Facility is supported in part by National Institutes of Health Program S10 (Award 1S1OD018136-01). Research in the P.Z. laboratory is supported by National Science Foundation Grant MCB-0923840. J.S.R.-E. received fellowship support from the Secretaría Nacional de Educación Superior, Ciencia, Tecnología, e Innovación, Ecuador.
Funders | Funder number |
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National Science Foundation | MCB-0923840 |
National Institutes of Health | |
NIH Office of the Director | S10OD018136 |
Secretaría de Educación Superior, Ciencia, Tecnología e Innovación |
Keywords
- Agrobacterium tumefaciens
- Multipartite genomes
- Polar growth
- PopZ and PodJ
- Replication and segregation