title: Expression of the Escherichia coli ftsZ gene: trials and tribulations of gene fusion studies.
abstract: The ftsZ gene of Escherichia coli, which codes for an essential cell division protein, is subjected to multiple regulation, as shown in part with studies using an ftsZ::lacZ operon fusion located on phage lambda JFL100. Using this same fusion, we sought to isolate regulatory mutants overexpressing ftsZ by selecting mutants able to grow on lactose. One Lac+ mutant was obtained which overexpressed the ftsZ::lacZ fusion 70-fold. The mutation responsible for the overexpression lies in a new gene, cot, located near 56 min on the E. coli genetic map. The cot mutation probably affects the transcription of a chromosomal open reading frame, ORF1, lying downstream of the bioA gene and adjacent to the ftzZ::lacZ fusion of the lambda JFL100 prophage integrated at att lambda. Using an ftsZ84(Ts) strain, in which there was a double selection for overexpression of both ftsZ::lacZ and ftsZ+, no Lac+Tr mutants were obtained from 3.6 x 10(10) bacteria; the introduction of a mutL allele, increasing spontaneous base substitution mutation rates 75-fold, did not permit us to isolate such a mutant. We conclude that Lac+ ftsZ-constitutive mutations cannot be obtained in lambda JFL100 lysogens by a single base substitution.
authors: Institut Jacques Monod, C.N.R.S., Université Paris, France.
authors: A
authors: A
authors: Robin
authors: R
authors: R
authors: D'Ari
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D010582:Bacteriophage lambda / Q000235:genetics; D003001:Cloning, Molecular; D003598:Cytoskeletal Proteins; D004926:Escherichia coli / Q000235:genetics*; D015870:Gene Expression; D007763:Lac Operon; D007785:Lactose / Q000378:metabolism; D009154:Mutation
chemical_list: D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; C071525:FtsZ protein, Bacteria; D007785:Lactose