This is illustrated by dual mutation of the Piu and Pia iron uptake ABC transporters alone or deletion of lgt, possibly leading to failure to retain lipoproteins on the cell membrane, both of which completely abrogate S. pneumoniae virulence in mice models of pneumonia (Brown et al., 2001a; Petit et al., 2001). The gene discussed is ABCG2; the disease is pneumonia.