Structural Analysis of Four Large Plasmids Harboring in a Unicellular Cyanobacterium, Synechocystis sp. PCC 6803

Abstract

The genome of the unicellular cyanobacterium Synechocystis sp. PCC 6803 consists of a single chromosome and several plasmids of different sizes, and the nucleotide sequences of the chromosome and three small plasmids (5.2 kb, 2.4 kb, and 2.3 kb) have already been sequenced. We newly determined the nucleotide sequences of four large plasmids, which have been identified in our laboratory (pSYSM:120 kb, pSYSX:106 kb, pSYSA:103 kb, and pSYSG:44 kb). Computer-aided analysis was performed to explore the genetic information carried by these plasmids. A total of 397 potential protein-encoding genes were predicted, but little information was obtained about the functional relationship of plasmids to host cell, as a large portion of the predicted genes (77%) were of unknown function. The occurrence of the potential genes on plasmids was divergent, and parA was the only gene common to all four large plasmids. The distribution data of a Cyanobacterium-specific sequence (HIP1: 5'-GCGATCGC-3') suggested that respective plasmids could have originated from different cyanobacterial strains.

A Transcriptional Regulator Sll0794 Regulates Tolerance to Biofuel Ethanol in Photosynthetic Synechocystis sp. PCC 6803

“…PCC 6803 were downloaded from NCBI, the Comprehensive Microbial Resource (CMR) of TIGR (http://www.tigr. org/CMR) and CyanoBase (http://genome.microbedb.jp/cyanobase/) (27). The Synechocystis sp.…”

“…The Synechocystis sp. PCC 6803 genome contains 3569 predicted protein (27). The ratio between the mutant and the wild type was obtained directly based on the protein abundance for any given protein.…”

“…Mutants-Survey of the Synechocystis genome revealed at least 40 genes encoding putative transcriptional regulators (27). So far only a dozen of them have ever been functionally characterized and the results showed that they were involved in regulation of a wide-range of physiological functions, such as nitrogen assimilation (38), inorganic carbon starvation and osmotic stress (39), high-affinity bicarbonate transporting (40), biogenesis of photosystem I (41), photosystem stoichiometry in response to high light (42), ferric uptake (43), and heat response (44).…”

The complete sequence and functional analysis of pANL, the large plasmid of the unicellular freshwater cyanobacterium Synechococcus elongatus PCC 7942

“…There are 7 plasmids in Synechocystis sp. PCC 6803 (Kaneko et al, 2003;Xu and McFadden, 1997;Yang and McFadden, 1993;Yang and McFadden, 1994) and 6 in Nostoc (also known as Anabaena) sp. PCC 7120 (Kaneko et al, 2001).…”

“…Three other twocomponent systems have been identified on the plasmids of Synechocystis sp. PCC 6803 (Kaneko et al, 2003), and they were shown not to be involved in the perception of hyperosmotic stress (Paithoonrangsarid et al, 2004). The real function of these plasmid-born two-component systems is yet to be explored.…”