CLONING AND CHARACTERIZATION OF AN FTSZ HOMOLOG FROM A BACTERIAL SYMBIONT OF DROSOPHILA-MELANOGASTER

A 1194 bp open reading frame that codes for a 398 amino acid peptide w as cloned from a lambdagt11 library of Drosophila melanogaster genomic DNA. The predicted peptide sequence is very similar to three previous ly characterized protein sequences that are encoded by the ftsZ genes in Escherichia coli, Bacillus subtilis and Rhizobium meliloti. The Fts Z protein has a major role in the initiation of cell division in proka ryotic cells. Using a tetracycline treatment that eradicates bacterial parasites from insects, the ftsZ homologue has been found to be deriv ed from a bacterium that lives within the D. melanogaster strain. Howe ver, polymerase chain reaction (PCR) amplification of the gene from tr eated embryos suggests that it is not derived from a gut bacterium. Ne vertheless, by amplifying and characterizing part of the 16S rRNA from this bacterium we have been able to demonstrate that it is a member o f the genus Wolbachia, a parasitic organism that infects, and disturbs the sexual cycle of various strains of Drosophila simulans. We sugges t that this ftsZ homologue is implicated in the cell division of Wolba chia, an organism that fails to grow outside the host organism. Sequen ce and alignment analysis of this ftsZ homologue show the presence of a potential GTP-binding motif indicating that it may function as a GTP ase. The consequences of this function particularly with respect to it s role in cell division are discussed.