The galE gene encoding the UDP-galactose 4-epimerase of Brevibacterium lactofermentum is coupled transcriptionally to the dmdR gene.

The galE gene of Brevibacterium lactofermentum, encoding UDP-galactose 4-epimerase (EC 5.1.3.2), has been identified by DNA sequencing downstream from the orf1-sigB-dmdR region. The arrangement of the sigB-dtxR-galE cluster is also conserved in Corynebacterium diphtheriae. The deduced galE product was a protein of 329 aa residues (35.4 kDa) that shared a high degree of identity to known UDP-galactose 4-epimerase proteins from Gram-positive microorganisms (Streptomyces lividans and Streptococcus thermophilus). Transcriptional analysis of the dmdR and galE genes in nutrient-rich medium showed that these genes are part of an operon, that is actively transcribed as a bicistronic mRNA during the exponential growth phase, but transcription of the operon is decreased during the stationary growth phase. In addition, the dmdR gene was also expressed as a monocistronic 0.7-kb transcript during the active growth phase.