RecD Plays an Essential Function During Growth at Low Temperature in the Antarctic Bacterium Pseudomonas syringae Lz4W
| Autor: | Ajit K. Satapathy, K Regha, M. K. Ray |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Alkylating Agents
Ultraviolet Rays Operon Mitomycin Molecular Sequence Data Mutant Antarctic Regions Pseudomonas syringae Mutagenesis (molecular biology technique) Apoptosis Investigations Biology medicine.disease_cause Radiation Tolerance Open Reading Frames Escherichia coli Genetics medicine Amino Acid Sequence Cloning Molecular Gene Mutation Cell Death Sequence Homology Amino Acid Escherichia coli Proteins Genetic Complementation Test DNA Drug Tolerance Gene Expression Regulation Bacterial Sequence Analysis DNA Cold Temperature Genes Bacterial DNA Transposable Elements Mutagenesis Site-Directed Transposon mutagenesis DNA Damage |
| Zdroj: | Genetics. 170:1473-1484 |
| ISSN: | 1943-2631 |
| DOI: | 10.1534/genetics.104.038943 |
| Popis: | The Antarctic psychrotrophic bacterium Pseudomonas syringae Lz4W has been used as a model system to identify genes that are required for growth at low temperature. Transposon mutagenesis was carried out to isolate mutant(s) of the bacterium that are defective for growth at 4° but normal at 22°. In one such cold-sensitive mutant (CS1), the transposon-disrupted gene was identified to be a homolog of the recD gene of several bacteria. Trans-complementation and freshly targeted gene disruption studies reconfirmed that the inactivation of the recD gene leads to a cold-sensitive phenotype. We cloned, sequenced, and analyzed ∼11.2 kbp of DNA from recD and its flanking region from the bacterium. recD was the last gene of a putative recCBD operon. The RecD ORF was 694 amino acids long and 40% identical (52% similar) to the Escherichia coli protein, and it could complement the E. coli recD mutation. The recD gene of E. coli, however, could not complement the cold-sensitive phenotype of the CS1 mutant. Interestingly, the CS1 strain showed greater sensitivity toward the DNA-damaging agents, mitomycin C and UV. The inactivation of recD in P. syringae also led to cell death and accumulation of DNA fragments of ∼25–30 kbp in size at low temperature (4°). We propose that during growth at a very low temperature the Antarctic P. syringae is subjected to DNA damage, which requires direct participation of a unique RecD function. Additional results suggest that a truncated recD encoding the N-terminal segment of (1–576) amino acids is sufficient to support growth of P. syringae at low temperature. |
| Databáze: | OpenAIRE |
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