Characterization of a holin (HolNU3-1) in methicillin-resistant Staphylococcus aureus host.

The gene encoding holin protein HolNU3-1 from a clinical isolate of methicillin-resistant Staphylococcus aureus (MRSA) NU3-1 was cloned and expressed in S. aureus RN4220. HolNU3-1 encoded by the holNU3-1 gene, which is located upstream of the deleted endolysin gene, was functional. Expression of the holNU3-1 gene induced a decrease in culture turbidity and formation of translucent (empty ghost) cells in S. aureus. We found heterogeneity of the holin genes and diversity of the two-component lysis system, which consists of holin and endolysin, in MRSA hosts. We suggest that this diversity is important in the identification of the evolution of clinical isolates of S. aureus.