| Autor: |
Rossi, Maria-Silvia, Fetherston, Jacqueline D., Létoffé, Sylvie, Carniel, Elisabeth, Perry, Robert D., Ghigo, Jean-Marc |
| Zdroj: |
Infection and Immunity; November 2001, Vol. 69 Issue: 11 p6707-6717, 11p |
| Abstrakt: |
ABSTRACTYersinia pestispossesses a heme-protein acquisition system (Hmu) that allows it to utilize heme and heme-protein complexes as the sole sources of iron. Analysis of the Y. pestisCO92 genomic sequence revealed a second heme-protein acquisition gene cluster that shares homology with the hemophore-dependent heme acquisition system (Has system) of Serratia marcescens. This locus consisted of thehasRypreceptor gene, thehasAyphemophore gene, and genes encoding components of the HasAypdedicated ABC transporter factor (hasDEyp), as well as atonBhomologue (hasByp). By using a reconstituted secretion system in Escherichia coli, we showed that HasAypis a secreted heme-binding protein and that expression of HasAypis iron regulated in E. coli. The use of a transcriptional reporter fusion showed that the hasRADEBpromoter is Fur regulated and has increased activity at 37°C. Hemoglobin utilization via the Hasypsystem was studied with both E. coliand Y. pestis, for which hasand has hmumutant strains were used. No contribution of the Has system to heme utilization was observed in either E. colior Y. pestisunder the conditions we tested. Previously it was shown that a deletion of the Hmu system had no effect on the virulence of Y. pestisin a mouse model of bubonic plague. An Hmu−Has−double mutant also retained full virulence in this model of infection. This report constitutes the first attempt to investigate the contribution of the hemophore-dependent heme acquisition system in bacterial pathogenicity. |
| Databáze: |
Supplemental Index |
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