Polyamines are an essential class of metabolites found throughout all kingdoms in life.
Borrelia burgdorferi harbors no enzymes to synthesize or degrade polyamines yet does
contain a polyamine uptake system, potABCD. In this report, we describe the initial
characterization of this putative transport system. After several unsuccessful attempts to
inactivate potABCD, we placed the operon under the control of an inducible LacI
promoter expression system. Analyses of this construct confirmed that potABCD was
required for in vitro survival. Additionally, we demonstrated that the potABCD operon
were upregulated in vitro by low osmolarity. Previously, we had shown that low
osmolarity triggers the activation of the Rrp... More
Polyamines are an essential class of metabolites found throughout all kingdoms in life.
Borrelia burgdorferi harbors no enzymes to synthesize or degrade polyamines yet does
contain a polyamine uptake system, potABCD. In this report, we describe the initial
characterization of this putative transport system. After several unsuccessful attempts to
inactivate potABCD, we placed the operon under the control of an inducible LacI
promoter expression system. Analyses of this construct confirmed that potABCD was
required for in vitro survival. Additionally, we demonstrated that the potABCD operon
were upregulated in vitro by low osmolarity. Previously, we had shown that low
osmolarity triggers the activation of the Rrp2/RpoN/RpoS regulatory cascade which
regulates genes essential for the transmission of spirochetes from ticks to mammalian
hosts. Interestingly, induction of the pot operon was only affected in an rpoS mutant but
not in a rpoN mutant, suggesting that the genes were RpoS-dependent, RpoNindependent. Furthermore, potABCD was upregulated during tick feeding concomitant
with the initiation of spirochete replication. Finally, uptake experiments determined the
specificity of B. burgdorferi’s PotABCD for spermidine.
