One such system that has proven effective in the malaria parasite P. falciparum, involves expressing recombinant proteins fused to the degradation domain of E. coli dihydrofolate reductase (DHFR-DD), which is stabilized in the presence of the folate analogue antibiotic trimethoprim (TMP) (Muralidharan et al.2011). The gene discussed is DHFR; the disease is malaria.