FtsZ of Filamentous, Heterocyst-Forming Cyanobacteria Has a Conserved N-Terminal Peptide Required for Normal FtsZ Polymerization and Cell Division

• Published in: Frontiers in microbiology 2018-10, Vol.9, p.2260-2260
• Main Authors: Corrales-Guerrero, Laura, Camargo, Sergio, Valladares, Ana, Picossi, Silvia, Luque, Ignacio, Ochoa de Alda, Jesús A G, Herrero, Antonia
• Format: Article
• Language: English
• Subjects: Anabaena; bacterial multicellularity; cell division; cyanobacterial FtsZ phylogeny; Microbiology; ZipN phylogeny
• ISSN: 1664-302X; 1664-302X
• DOI: 10.3389/fmicb.2018.02260

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 .