Instability of the mutated biotin operon plasmid in a biotin-producing mutant of Serratia marcescens.
The growth of a d-biotin-producing strain of Serratia marcescens (SB412) was strongly inhibited by the introduction of pLGM412, a low-copy-number plasmid containing the complete biotin (bio) operon derived from SB412, whereas the wild-type strain was not inhibited by the plasmid. SB412 carrying pLGM412 was genetically unstable; large colonies appeared spontaneously from the background small colonies. When the plasmids from the large colonies were transformed into the SB412 host, all of the resultant transformants showed a large-colony phenotype, suggesting that the large-colony phenotype is due to mutations in the plasmid-born bio genes. Some of these plasmids were structurally altered and the others were not. Furthermore, the structurally altered plasmids were classified into a deleted and an elongated type. All of the mutated pLGM412 derivatives reduced or lacked the bio gene expression, indicating that the high expression of bio gene(s) causes the growth inhibition. By subcloning experiments, biotin synthase (the bioB gene product) was responsible for the growth inhibition.
Sakurai
N
N
Research Laboratory of Applied Biochemistry, Tanabe Seiyaku Co., Ltd., Osaka, Japan.
Imai
Y
Y
Komatsubara
S
S
D001426:Bacterial Proteins / Q000235:genetics; D001710:Biotin / Q000096:biosynthesis* / Q000235:genetics*; D002455:Cell Division / Q000235:genetics; D029968:Escherichia coli Proteins; D009154:Mutation; D009876:Operon; D010957:Plasmids / Q000235:genetics*; D011938:Rec A Recombinases / Q000235:genetics; D015183:Restriction Mapping; D012706:Serratia marcescens / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D013466:Sulfurtransferases; D014170:Transformation, Genetic
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D001710:Biotin; D011938:Rec A Recombinases; D013466:Sulfurtransferases; C087072:biotin synthase, E coli