集胞藻的随机插入诱变和光激活异养突变株的筛选

RANDOM INSERTION MUTAGENESIS OF SYNECHOCYSTIS SP.PCC6803 AND SELECTION OF LAHG MUTANTS

以４－碱基限制性内切酶部分酶切集胞藻ＰＣＣ６８０３基因文库总质粒ＤＮＡ，并插入卡那霉素抗性基因标记，构建了二级随机插入诱变文库。以该诱变文库总ＤＮＡ转化集胞藻ＰＣＣ６８０３，得到大量有抗性标记基因随机插入的转化子。利用这一方法获得了不能迸行光激活异养生长的突变株，并克隆了抗性标记基因插入部位 ＤＮＡ片段。在持续光照但加 ＤＣＭＵ抑制光合作用的情况下，这些突变株仍然能够利用葡萄糖异养生长，推测突变基因与短时光信号的感应有关。

A secondary library for random insertion mutagenesis in Synechocystis sp. PCC6803 was constructed by partial digestion of total plasmid DNA of its primary library and ligation with a kanamycin-resistance marker cassette. Total DNA of the mutagenesis library was applied to transformation of Synechocystis 6803, resulting in a large number of transformants whose genomes were inserted with the marker cassette. Using this method, the authors obtained mutants that were incapable of light-activated heterotrophic growth and cloned DNA fragments around the inserted region. Under continuous illumination but with DCMU inhibiting photosynthesis, these mutants are capable of heterotrophic growth on glucose, which suggests that the mutated genes are related to signal transduction in response to brief light exposure.