Cloning, sequencing, and characterization of the ftsZ gene from coryneform bacteria.

Taking advantage of highly conserved domains present in the ftsZ genes from Escherichia coli, Rhizobium meliloti, and Bacillus subtilis, we designed degenerate oligonucleotides (oligos) corresponding to these regions. These oligos were used as primers in PCR in order to amplify DNA sequences from Brevibacterium flavum MJ233 chromosomal DNA. The PCR product was used as a probe to recover genomic fragments from a lambda library of Br. flavum MJ233. The complete nucleotide sequence (nt) of the cloned 4.2-kb EcoRI fragment containing the ftsZ homolog from Br. flavum MJ233 indicated that the deduced gene product of the Br. flavum ftsZ homolog is composed of 438 amino acids (aa) with a deduced molecular weight of 46.9 kDa. This size of molecular weight was also confirmed by the in vitro protein synthesis assay. Comparison of this aa sequence to the corresponding sequences from E. coli, Rh. meliloti, B. subtilis, and Streptomyces coelicolor revealed a high degree of conservation and suggested that the Br. flavum ftsZ homolog has a putative GTP binding motif and a GTP hydrolizing region. Expression of Br. flavum ftsZ gene in E. coli, JM109 inhibited its cell division, leading to filamentation. This suggested that the Br. flavum ftsZ product competed with the E. coli ftsZ product.