pestis isolated from fleas [9]. However, actual levels of the Y. pestis Tc proteins in the flea or Entospletinib molecular weight during growth in liquid culture, or a potential role in survival within or transmission from the flea have not yet been determined. In this study, we show that the Tc proteins YitA and YipA are highly produced by Y. pestis in the flea but not during growth in culture at the same temperature (22°C) and that over-production of YitR increases YitA and YipA synthesis

in vitro. YitA and YipA production was greatest during growth at lower temperatures (less than 22°C) and minimally produced at 37°C, although the proteins persisted for more than 9 hours after a transition from 22°C to 37°C. YipA appears to be processed near the C-terminus between the click here RhsA and PTP domains. Furthermore, YitA and YipA are localized to the outer membrane, and YitA is surface-exposed. We also show that the Y. pestis Tc proteins do not play a detectable role in X. cheopis infection or the ability to produce a transmissible infection. Results YitA and YipA are synthesized in the flea P5091 but not in vitro unless the YitR regulator is over-produced A diagram of the Y. pestis Tc locus is shown in Figure 1a. X. cheopis fleas were infected with KIM6+ or KIM6+ΔyitA-yipB (Figure 1A) to compare YitA and YipA (Figure 1B) protein levels following

growth in the flea to growth in BHI culture. YitA and YipA were both highly produced by Y. pestis in the flea (Figure 2, lane 2) compared to stationary phase BHI cultures (Figure 2, lane 4) incubated at 22°C, the same temperature at which the fleas were maintained. YitA was detected as a prominent band around 95 kDa, which corresponded to the expected size based on the YitA amino acid sequence. YipA was selleck chemicals llc detected as two major bands. The smaller band at ~73 kDa was the most prominent. The larger band at ~106 kDa corresponds to the full length YipA predicted by its amino acid sequence and with recombinant YipA synthesized in and purified from E. coli (Figure 2, lane 9). Figure 2 YitA and YipA are only detectable in Y. pestis isolated from fleas

but over-production of YitR increases their synthesis in vitro . Lane 1, molecular weight ladder. Lane 2, Y. pestis KIM6+ isolated from infected fleas. Lane 3, KIM6+ΔyitA-yipB isolated from infected fleas. Lane 4, KIM6+ grown at 22°C in BHI. Lane 5, KIM6+ (pWKS130::yitR) grown at 22°C in BHI. Lane 6, KIM6+ (pCR-XL-TOPO::yitR) grown at 22°C in BHI. Lane 7, KIM6+ΔyitA-yipB (pCR-XL-TOPO::yitR) grown at 22°C in BHI. Lanes 8–9, recombinant YitA and YipA purified from E. coli. Panels show Western blots probed with anti-YitA, anti-YipA, or anti-Ail (sample loading control) antiserum. To determine if over-production of YitR would result in increased levels of YitA and YipA proteins during growth in vitro, the regulator yitR was cloned with its native promoter into the low-copy plasmid pWKS130 and the high-copy plasmid pCR-XL-TOPO. Y.