CRISPR-Cas in antibiotics-producing actinomycetes

Abstract

Actinomycetes are a diverse group of bacteria with important properties for medicine and industry. Most of the antibiotics used today originate from actinomycetes. The production of biologically active natural products protects actinomycetes against competitors in the environment. The prokaryotic immune system CRISPR-Cas offers protection against phages and foreign DNA/RNA. It is found in about 50 per cent of all actinomycetes genomes. Apart from a few examples, the function of CRISPR-Cas in actinomycetes has barely been investigated so far. The characterized systems of S. avermitilis and M. tuberculosis show atypical features. In S. avermitilis, the activity of the CRISPR-Cas systems is linked to the phase of its life cycle. In M. tuberculosis, crRNA maturation differs from similar systems. Our studies of S. tenebrarius CRISPR-Cas systems suggest a possible involvement in cell differentiation.