Fructose utilization and pathogenicity of Spiroplasma citri: characterization of the fructose operon.
Transposon Tn4001 mutagenesis of Spiroplasma citri wild-type (wt) strain GII-3 led to the isolation and characterization of non-phytopathogenic mutant GMT 553. In this mutant, transposon Tn4001 is inserted within the first gene of the fructose operon. This operon comprises three genes. The first gene (fruR) codes for a putative transcriptional regulator protein belonging to the deoxyribonucleoside repressor (DeoR) family. Sequence similarities and functional complementation of mutant GMT 553 with different combinations of the wt genes of the fructose operon showed that the second gene (fruA) codes for the permease of the phosphoenolpyruvate:fructose phosphotransferase system (fructose PTS), and the third, fruK, for the 1-phosphofructokinase (1-PFK). Transcription of the fructose operon in wt strain GII-3 resulted in two messenger RNAs, one of 2.8kb and one of 3.8kb. Insertion of Tn4001 in the genome of mutant GMT 553 abolished transcription of the fructose operon, and resulted in the inability of this mutant to use fructose. Functional complementation experiments demonstrated that fructose utilization was restored with fruR-fruA-fruK, fruA-fruK or fruA only, but not with fruR or fruR-fruA. This is the first time that an operon for sugar utilization has been functionally characterized in the mollicutes.
Gaurivaud
P
P
Laboratoire de Biologie Cellulaire et Moléculaire, Institut de Biologie Végétale Moléculaire, Institut National de la Recherche Agronomique, Université Victor Segalen Bordeaux 2, 71 avenue Edouard Bourleaux, Cedex, France.
Laigret
F
F
Garnier
M
M
Bove
J M
JM
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D001665:Binding Sites; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005632:Fructose / Q000378:metabolism*; D005816:Genetic Complementation Test; D026901:Membrane Transport Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins; D016254:Mutagenesis, Insertional; D009154:Mutation; D009876:Operon / Q000235:genetics*; D010448:Peptide Initiation Factors / Q000235:genetics; D010641:Phenotype; D010732:Phosphofructokinase-1 / Q000235:genetics; D020161:Physical Chromosome Mapping; D039881:Prokaryotic Initiation Factor-2; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics; D017422:Sequence Analysis, DNA; D013149:Spiroplasma / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D014157:Transcription Factors / Q000235:genetics; D014158:Transcription, Genetic; D056968:Lac Repressors
D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D005632:Fructose; D026901:Membrane Transport Proteins; D009004:Monosaccharide Transport Proteins; D010448:Peptide Initiation Factors; D010732:Phosphofructokinase-1; D039881:Prokaryotic Initiation Factor-2; D012329:RNA, Bacterial; D012097:Repressor Proteins; D014157:Transcription Factors; C104848:FruA protein, Myxococcus xanthus; C098926:fructose permease; C068837:FruR protein, Bacteria; D056968:Lac Repressors; C068652:1-phosphofructokinase