Satoru Watanabe | Cyanobacterial multi-copy chromosomes and their replication
Channel: CyanoWorld
Date: 2022-04-13

Satoru Watanabe - Tokyo University of Agriculture, Japan

Homepage: http://dbs.nodai.ac.jp/view?l=en&u=275
Research Gate: https://www.researchgate.net/profile/Satoru-Watanabe-4

Cyanobacterial multi-copy chromosomes and their replication

Cyanobacteria have oxygen-producing photosynthetic capabilities, meaning that they can produce biomass by using solar energy, and they have recently gained attention for their potential as green cell factories for CO2-neutral biosynthesis of various products. Exploitation of cyanobacteria for bioengineering requires full understanding of cyanobacterial proliferation mechanism. However, the information of proliferation mechanism in cyanobacteria was limited.
Several freshwater cyanobacteria contain multiple chromosome copies per cell throughout their cell cycle, which is known as polyploidy, while the model bacteria, such as Escherichia coli and Bacillus subtilis, harbor single chromosomes. In addition, the polyploidy cyanobacteria are also unique in their genome structure. 
In this seminar, I will talk about the current knowledge of growth mechanism in the model cyanobacterium Synechococcus elongatus PCC 7942, focusing on the DNA replication mechanism of multiple copy chromosomes. In S. elongatus 7942, DNA replication is initiated from single site (oriC) in a light-dependent manner. Interestingly, chromosome replication is asynchronous both among cells and chromosomes: multiple copy chromosomes were found to be sequentially duplicated one by one. In addition, comparative analysis of several freshwater cyanobacteria suggests diversity in DNA replication initiation mechanisms. It is worth noting that the occurrence of polyploidy and its regulation are correlated with certain cyanobacterial lifestyles.

This talk is part of the CyanoWorld online seminar series, hosted by Nicolas Schmelling and Ilka Axmann, and was held on Zoom on March 24th, 2022.

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