Isolation, characterization, and complementation of a motility mutant of Spiroplasma citri

• Published in: Journal of Bacteriology Vol. 179; no. 15; pp. 4802 - 4810
• Main Authors: Jacob, C. (Universite Victor Segalen Bordeaux 2, Villenave d'Ornon, France.), Nouzieres, F, Duret, S, Bove, J.M, Renaudin, J
• Format: Journal Article
• Language: English
• Published: United States American Society for Microbiology 01.08.1997
• Subjects: Amino Acid Sequence; AMINO ACID SEQUENCES; Bacteria; BACTERIAL PROTEINS; Bacteriology; Base Sequence; Cellular biology; CHEMICAL COMPOSITION; COMPOSICION QUIMICA; COMPOSITION CHIMIQUE; DNA Transposable Elements; DNA, Bacterial; Drug Resistance, Microbial - genetics; GENBANK/U89875; GENE; GENES; Genetic Complementation Test; GENETIC TRANSFORMATION; GENETICA; GENETICS; GENETIQUE; Gentamicins - pharmacology; INSERTION; MICROBIAL PROTEINS; MOLECULAR SEQUENCE DATA; MOUVEMENT; MOVEMENT; MOVIMIENTO; MUTACION; Mutagenesis, Insertional; MUTANT; MUTANTES; MUTANTS; MUTATION; NUCLEOTIDE SEQUENCE; OPEN READING FRAMES; PEPTIDE; PEPTIDES; PEPTIDOS; POLYPEPTIDES; PROTEINAS MICROBIANAS; PROTEINE MICROBIENNE; SCM1 GENE; SECUENCIA NUCLEOTIDICA; Sequence Analysis, DNA; SEQUENCE NUCLEOTIDIQUE; SPIROPLASMA; Spiroplasma - genetics; Spiroplasma - physiology; STRUCTURAL GENES; TRANSFORMACION GENETICA; TRANSFORMATION GENETIQUE; Transformation, Bacterial; TRANSPOSABLE ELEMENTS
• ISSN: 0021-9193; 1098-5530; 1067-8832
• DOI: 10.1128/jb.179.15.4802-4810.1997

The helical mollicute Spiroplasma citri, when growing on low-agar medium, forms fuzzy colonies with occasional surrounding satellite colonies due to the ability of the spiroplasmal cells to move through the agar matrix. In liquid medium, these helical organisms flex, twist, and rotate rapidly. By using Tn4001 insertion mutagenesis, a motility mutant was isolated on the basis of its nondiffuse, sharp-edged colonies. Dark-field microscopy observations revealed that the organism flexed at a low frequency and had lost the ability to rotate about the helix axis. In this mutant, the transposon was shown to be inserted into an open reading frame encoding a putative polypeptide of 409 amino acids for which no significant homology with known proteins was found. The corresponding gene, named scm1, was recovered from the wild-type strain and introduced into the motility mutant by using the S. citri oriC plasmid pBOT1 as the vector. The appearance of fuzzy colonies and the observation that spiroplasma cells displayed rotatory and flexional movements showed the motile phenotype to be restored in the spiroplasmal transformants. The functional complementation of the motility mutant proves the scm1 gene product to be involved in the motility mechanism of S. citri