The control region of the F plasmid transfer operon: DNA sequence of the traJ and traY genes and characterisation of the traY leads to Z promoter

Abstract

The complete nucleotide sequence of the F plasmid transfer genes traJ and traY, together with the promoter-proximal region of the traA gene has been determined. The traJ reading frame has been confirmed by sequencing the traJ90 amber mutant allele. The predicted amino acid sequence of the TraJ protein shows that this outer-membrane protein lacks a signal sequence. The pattern of codon usage within the traJ gene is different from that of genes for abundant outer-membrane proteins and is closer to that of genes that are expressed at relatively low levels. We have located the traY leads to Z operon promoter by in vitro run-off transcription experiments and have developed in vivo assays for the activity of the promoter by fusing it to galactokinase and kanamycin-resistance genes.