Corrales-Guerrero Laura, Camargo Sergio, Valladares Ana, Picossi Silvia, Luque Ignacio, Ochoa de Alda Jesús A G, Herrero Antonia
Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Seville, Spain.
Facultad de Formación del Profesorado, Universidad de Extremadura, Cáceres, Spain.
Front Microbiol. 2018 Oct 2;9:2260. doi: 10.3389/fmicb.2018.02260. eCollection 2018.
Filamentous cyanobacteria grow by intercalary cell division, which should involve distinct steps compared to those producing separate daughter cells. The N-terminal region of FtsZ is highly conserved in the clade of filamentous cyanobacteria capable of cell differentiation. A derivative of the model strain sp. PCC 7120 expressing only an FtsZ lacking the amino acids 2-51 of the N-terminal peptide (ΔN-FtsZ) could not be segregated. Strain CSL110 expresses both ΔN-FtsZ, from the endogenous gene promoter, and the native FtsZ from a synthetic regulated promoter. Under conditions of ΔN-FtsZ predominance, cells of strain CSL110 progressively enlarge, reflecting reduced cell division, and show instances of asymmetric cell division and aberrant Z-structures notably differing from the Z-ring formed by FtsZ in the wild type. In bacterial 2-hybrid assays FtsZ interacted with ΔN-FtsZ. However, ΔN-FtsZ-GFP appeared impaired for incorporation into Z-rings when expressed together with FtsZ. FtsZ, but not ΔN-FtsZ, interacted with the essential protein SepF. Both FtsZ and ΔN-FtsZ polymerize exhibiting comparable GTPase activities. However, filaments of FtsZ show a distinct curling forming toroids, whereas ΔN-FtsZ form thick bundles of straight filaments. Thus, the N-terminal FtsZ sequence appears to contribute to a distinct FtsZ polymerization mode that is essential for cell division and division plane location in .
丝状蓝细菌通过居间细胞分裂生长，与产生独立子细胞的分裂过程相比，这一过程应涉及不同的步骤。FtsZ的N端区域在能够进行细胞分化的丝状蓝细菌分支中高度保守。模式菌株集胞藻属PCC 7120的一个衍生物，仅表达缺少N端肽2 - 51位氨基酸的FtsZ（ΔN - FtsZ），无法进行细胞分裂。菌株CSL110从内源性基因启动子表达ΔN - FtsZ，并从合成调控启动子表达天然FtsZ。在ΔN - FtsZ占优势的条件下，CSL110菌株的细胞逐渐增大，这反映出细胞分裂减少，并出现不对称细胞分裂的情况以及与野生型中由FtsZ形成的Z环明显不同的异常Z结构。在细菌双杂交试验中，FtsZ与ΔN - FtsZ相互作用。然而，当与FtsZ一起表达时，ΔN - FtsZ - GFP掺入Z环的能力似乎受损。FtsZ与必需蛋白SepF相互作用，而ΔN - FtsZ则不然。FtsZ和ΔN - FtsZ都能聚合，表现出相当的GTP酶活性。然而，FtsZ的丝状物呈现出独特的卷曲形成环形，而ΔN - FtsZ形成厚的直丝束。因此，FtsZ的N端序列似乎有助于形成一种独特的FtsZ聚合模式，这对于集胞藻属的细胞分裂和分裂平面定位至关重要。
