Akiyama H, Kanai S, Hirano M, Miyasaka H
Biological Sciences Department, Toray Research Center, Inc., Kanagawa, Japan.
DNA Res. 1998 Apr 30;5(2):127-9. doi: 10.1093/dnares/5.2.127.
We have determined the complete nucleotide sequence of pAQ1, the smallest plasmid of the unicellular marine cyanobacterium Synechococcus sp. PCC7002. The plasmid consists of 4,809 bp and has at least four open reading frames that potentially encode polypeptides of 50 or more amino acids. We found that a palindromic element, the core sequence of which is G(G/A)CGATCGCC, is over-represented not only in plasmid pAQ1 but also in the accumulated cyanobacterial genomic sequences from Synechococcus sp. PCC6301, PCC7002, PCC7942, vulcanus and Synechocystis sp. PCC6803 within GenBank and EMBL databases. It suggests that this sequence might mediate gene rearrangement, thus increasing genetic diversity, since recombination events are frequent in cyanobacteria.
我们已经确定了单细胞海洋蓝藻聚球藻属PCC7002最小的质粒pAQ1的完整核苷酸序列。该质粒由4809个碱基对组成，至少有四个开放阅读框，可能编码50个或更多氨基酸的多肽。我们发现，一种回文元件，其核心序列为G(G/A)CGATCGCC，不仅在质粒pAQ1中大量存在，而且在GenBank和EMBL数据库中聚球藻属PCC6301、PCC7002、PCC7942、火山聚球藻和集胞藻属PCC6803积累的蓝藻基因组序列中也大量存在。这表明该序列可能介导基因重排，从而增加遗传多样性，因为蓝藻中的重组事件很频繁。
