Part:BBa_K535008

repC - ctRNA

The widespread replicons of repABC and repC families from α-proteobacteria share high similarity in their replication initiator proteins (RepC). repC region belongs to a low copy-number plasmid pRmeGR4a from Sinorizobium meliloti GR4. This region contains only two genes: one encoding the initiator protein RepC (46.8 kDa) and other, an antisense RNA (67 nt).

The constitutively expressed countertranscribed RNA (ctRNA) forms a single stem–loop structure that acts as an intrinsic rho-independent terminator. Transcriptional activity of ctRNA downregulates repC, both have σ⁷⁰-like promoters. Tha promoter that regulates repC (T1) is relatively far from the transcription start site and is influenced by the ctRNA transcription which has its own promoter in reverse direction.

Compatibility between plasmids is the ability to get two or more classes of plasmids at the same organism. The ctRNA is a strong trans-incompatibility factor and negative regulator of repC expression [1], this has been seen in other families of RepC class [2].

RepC is the minimal region required for stable replication of a member of the repC family, it works in Rhizobials.

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  INCOMPATIBLE WITH RFC[12]

  Illegal NotI site found at 835
  
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  INCOMPATIBLE WITH RFC[25]

  Illegal NgoMIV site found at 916
  
• 1000
  INCOMPATIBLE WITH RFC[1000]

  Illegal BsaI site found at 761
  Illegal SapI site found at 955