RNase J1 and J2 Are Host-Encoded Factors for Plasmid Replication

Area of Science:

• Molecular Biology
• Microbiology
• Genetics

Background:

• Plasmids must replicate efficiently without burdening host cells.
• Copy-number control is essential for plasmid stability and host health.
• Small RNAs regulate plasmid replication in response to host cell conditions.

Purpose of the Study:

• Investigate the regulatory mechanism of pSA564 plasmid replication.
• Identify the role of antisense RNA1 in controlling plasmid copy-number.
• Determine host factors involved in plasmid stability.

Main Methods:

• Investigated antisense RNA1 regulation of the repA gene's 5' untranslated region (5'UTR).
• Analyzed the effects of RNA1 overexpression on bacterial host cells.
• Identified host-encoded exoribonucleases RNase J1 and J2 responsible for RNA1 degradation.

Main Results:

• Overexpression of antisense RNA1 inhibits pSA564 replication and cures the host.
• RNA1 binding to the repA 5'UTR shifts secondary structures, repressing transcription and translation.
• Absence of RNase J1 or J2 leads to RNA1 accumulation, blocking RepA expression and halting plasmid replication.

Conclusions:

• Antisense RNA1 is a key regulator of pSA564 copy-number control.
• Regulation occurs at both transcriptional and translational levels via RNA-RNA interactions.
• Host exoribonucleases RNase J1 and J2 are crucial for plasmid stability in Staphylococcus aureus.