Transcription and expression analysis, using lacZ and phoA gene fusions, of Mycobacterium fortuitum beta-lactamase genes cloned from a natural isolate and a high-level beta-lactamase producer.
The gene encoding a class A beta-lactamase was cloned from a natural isolate of Mycobacterium fortuitum (blaF) and from a high-level amoxicillin-resistant mutant that produces large amounts of beta-lactamase (blaF*). The nucleotide sequences of the two genes differ at 11 positions, including two in the region upstream from the coding sequence. Gene fusions to Escherichia coli lacZ and transcription and expression analysis of the cloned genes in Mycobacterium smegmatis indicated that high-level production of the beta-lactamase in the mutant is mainly or wholly due to a single base pair difference in the promoter. These analyses also showed that transcription and translation start at the same position. A comparison of the amino acid sequence of BlaF, as predicted from the nucleotide sequence, with the determined N-terminal amino acid sequence indicated the presence of a typical signal peptide. The fusion of blaF (or blaF*) to the E. coli gene phoA resulted in the production of BlaF-PhoA hybrid proteins that had alkaline phosphatase activity. These results demonstrate that phoA can be used as a reporter gene for studying protein export in mycobacteria.
Timm
J
J
Unité de Génétique Mycobactérienne, CNRS URA 1300, Institut Pasteur, Paris, France.
Perilli
M G
MG
Duez
C
C
Trias
J
J
Orefici
G
G
Fattorini
L
L
Amicosante
G
G
Oratore
A
A
Joris
B
B
Frère
J M
JM
D000469:Alkaline Phosphatase / Q000096:biosynthesis / Q000235:genetics; D000595:Amino Acid Sequence; D000668:Ampicillin Resistance / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D005798:Genes, Bacterial / Q000235:genetics*; D008969:Molecular Sequence Data; D009161:Mycobacterium / Q000201:enzymology / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D001616:beta-Galactosidase / Q000096:biosynthesis / Q000235:genetics; D001618:beta-Lactamases / Q000502:physiology*
D011993:Recombinant Fusion Proteins; D000469:Alkaline Phosphatase; D001616:beta-Galactosidase; D001618:beta-Lactamases