The traJ 5' UTR is a cis acting RNA element which is involved in regulating plasmid transfer in bacteria.

In conjugating bacteria

Bacterial conjugation

Bacterial conjugation is the transfer of genetic material between bacterial cells by direct cell-to-cell contact or by a bridge-like connection between two cells...

 the FinOP system regulates the transfer of F-like plasmids. The FinP

FinP

FinP encodes an antisense non-coding RNA gene that is complementary to part of the TraJ 5' UTR. The FinOP system regulates the transfer of F-like plasmids. The traJ gene encodes a protein required for transcription from the major transfer promoter, pY. The FinO protein is essential for effective...

 gene encodes an antisense RNA product that is complementary to part of the 5' UTR

Five prime untranslated region

A messenger ribonucleic acid molecule codes for a protein through translation. The mRNA also contains regions that are not translated: in eukaryotes these include the 5' untranslated region, 3' untranslated region, 5' cap and poly-A tail....

 of the traJ mRNA. The traJ gene encodes a protein required for transcription from the major transfer promoter, pY. The FinO protein is essential for effective repression, acting by binding to FinP and protecting it from RNase E degradation.