COTRANSCRIPTION OF 2 GENES NECESSARY FOR RIBOSOMAL PROTEIN-L11 METHYLATION (PRMA) AND PANTOTHENATE TRANSPORT (PANF) IN ESCHERICHIA-COLI K-12

Genetic complementation and enzyme assays have shown that the DNA regi on between panF, which encodes pantothenate permease, and orf1, the fi rst gene of the fis operon, encodes prmA, the genetic determinant for the ribosomal protein L11 methyltransferase. Sequencing of this region identified one long open reading frame that encodes a protein of 31,8 30 Da and corresponds to the prmA gene. We found, both in vivo and in vitro, that prmA is expressed from promoters located upstream of panF and thus that the panF and prmA genes constitute a bifunctional operon . We located the major 3' end of prmA transcripts 90 nucleotides downs tream of the stop codon of prmA in the DNA region upstream of the fis operon, a region implicated in the control of the expression of the fi s operon. Although no promoter activity was detected immediately upstr eam of prmA, S1 mapping detected 5' ends of mRNA in this region, imply ing that some mRNA processing occurs within the bicistronic panF-prmA mRNA.