Plasmid-dependent co-mutation in Streptomyces coelicolor A3(2)

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• Streptomyces coelicolor A3(2) harbors the SCP1 plasmid, which influences cellular processes.
• Chromosomal mutations can impact plasmid stability and DNA repair mechanisms.

Purpose of the Study:

• To investigate the relationship between a spontaneous chromosomal mutation (plc A(-)) and the SCP1 plasmid in Streptomyces coelicolor.
• To determine the role of the SCP1 plasmid in DNA repair and mutagenesis.

Main Methods:

• Induction of chromosomal mutation (plc A(-)) in Streptomyces coelicolor.
• Treatment with UV irradiation and MNNG (N-methyl-N'-nitro-N-nitrosoguanidine) mutagen.
• Plasmid curing and reintroduction experiments.
• Assessment of strain susceptibility to lethal effects and co-mutation.

Main Results:

• The plc A(-) mutation rendered the SCP1 plasmid susceptible to UV-induced curing.
• SCP1(-) strains showed increased sensitivity to UV lethality but were refractory to MNNG-induced co-mutation.
• Restoration of the SCP1 plasmid in plc A(-) strains re-established co-mutation proficiency and UV resistance.

Conclusions:

• The SCP1 plasmid likely carries a gene analogous to E. coli's uvrE gene, involved in DNA repair.
• The SCP1 plasmid plays a crucial role in protecting Streptomyces coelicolor against UV damage and facilitating co-mutation.