Xu Wen-Liang, Jeanjean Robert, Liu Yong-Ding, Zhang Cheng-Cai
Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, PR China.
FEBS Lett. 2003 Oct 9;553(1-2):179-82. doi: 10.1016/s0014-5793(03)01019-6.
In cyanobacteria, the isiA gene is required for cell adaptation to oxidative damage caused by the absence of iron. We show here that a putative Ser/Thr kinase gene, pkn22 (alr2052), is activated by iron deficiency and oxidative damage in Anabaena sp. PCC 7120. A pkn22 insertion mutant is unable to grow when iron is limiting. pkn22 regulates the expression of isiA (encoding CP43'), but not of isiB (encoding flavodoxin) and psbC (CP43). Fluorescence measurement at 77 K reveals the absence of the typical signature of CP43' associated with photosystem I in the mutant under iron-limiting conditions. We propose that Pkn22 is required for the function of isiA/CP43' and constitutes a regulatory element necessary for stress response.
在蓝细菌中，isiA基因是细胞适应因缺铁导致的氧化损伤所必需的。我们在此表明，一个假定的丝氨酸/苏氨酸激酶基因pkn22（alr2052）在鱼腥藻PCC 7120中被缺铁和氧化损伤激活。当铁受到限制时，pkn22插入突变体无法生长。pkn22调节isiA（编码CP43'）的表达，但不调节isiB（编码黄素氧还蛋白）和psbC（CP43）的表达。77K下的荧光测量显示，在铁限制条件下，突变体中不存在与光系统I相关的CP43'的典型特征。我们提出，Pkn22是isiA/CP43'功能所必需的，并且构成应激反应所必需的调节元件。
