A mutant cysteinyl-tRNA synthetase affecting timing of chromosomal replication initiation in B. subtilis and conferring resistance to a protein kinase C inhibitor.
A Bacillus subtilis mutant spnA95 was isolated as resistant at 30 degrees C to the protein kinase C (PKC) inhibitor, sphinganine, and temperature sensitive for growth. As deduced by flow cytometry measurements, the mutant has a 35% reduced initiation mass at permissive temperature, resulting in initiation of DNA replication much earlier in the cell cycle than in the wild type. This modification is accompanied by a change in cell size, as determined by phase-contrast microscopy and flow cytometry. Therefore, this strain displays the characteristics of a novel cell clock mutant. spnA is a newly identified gene in B.subtilis and was shown to encode a cysteinyl-tRNA synthetase. At non-permissive temperature, the mutant was defective in the synthesis of P70, a protein with several characteristics of PKC (a cysteine-rich protein). As one possibility, we propose that the altered timing of replication may be due to the reduced synthesis of specific cysteine-rich proteins normally involved in controlling chromosomal replication initiation in B. subtilis.
Séror
S J
SJ
Institut de Génétique et Microbiologie, URA CNRS 1354, Université Paris XI, Orsay, France.
Casarégola
S
S
Vannier
F
F
Zouari
N
N
Dahl
M
M
Boye
E
E
D000595:Amino Acid Sequence; D000604:Amino Acyl-tRNA Synthetases / Q000235:genetics*; D001412:Bacillus subtilis / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D001483:Base Sequence; D002455:Cell Division; D002876:Chromosomes, Bacterial; D004261:DNA Replication; D004269:DNA, Bacterial / Q000096:biosynthesis*; D005434:Flow Cytometry; D006358:Hot Temperature; D008969:Molecular Sequence Data; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D017386:Sequence Homology, Amino Acid; D013110:Sphingosine / Q000031:analogs & derivatives / Q000494:pharmacology; D013997:Time Factors
D004269:DNA, Bacterial; D011493:Protein Kinase C; D000604:Amino Acyl-tRNA Synthetases; C019975:cysteinyl-tRNA synthetase; D013110:Sphingosine; C005682:safingol