Characterization of the ftsZ cell division gene of Neisseria gonorrhoeae: expression in Escherichia coli and N-gonorrhoeae

We cloned the cell division gene ftsZ of the gramnegative coccus Neisseria gonorrhoeae (Ng) strain CH811, characterized it genetically and phenotypica lly. and studied its localization in N. gonorrhoeae and Escherichia coli (E c). The 1,179-bp ORF of ftsZ(Ng) encodes a protein with a predicted molecul ar mass of 41.5 kDa. Protein sequence alignments indicate that FtsZ(Ng) is similar to other FtsZ proteins and contains the conserved GTP binding motif . FtsZ homologues were identified in several N. gonorrhoeae strains and in Neisseria lactamica, Neisseria sicca, Neisseria polysaccharae and Neisseria cinerea either by stern blot or by PCR-Southern blot analysis. Attempts to inactivate the frsZ(Ng) on the chromosome failed, indicating that it in es sential far gonococcal growth. FtsZ(Ng) was synthesized in an in vitro tran scription/translation system and was shown to be 43 kDa, the same size as i n Western blots. Expression of the ftsZ(Ng) gene from nongonococcal promste rs resulted in a filamentous phenotype in E. coli. Under controlled express ion, the FtsZ(Ng)-GFP fusion protein localized at the mid-cell division sit e in E. coli. E. coli expressing high levels of the FtsZ(Ng)-GFP fusion pro tein formed filaments and exhibited different fluorescent structures includ ing helices, spiral tubules extending from pole to pole, and regularly spac ed dots or bands that did not localize at the middle of the cell. Expressio n of the FtsZ(Ng) -GFP fusion protein in N. gonorrhoeae resulted in abnorma l cell division as shown by electron microscopy. FtsZ(Ng)-GFP fusions were also expressed in a gonococcal background using a unique shuttle vector.