Rapid activation of distinct members of multigene families in Plasmodium spp.

Variant antigens that are encoded by large multigene families play an important role in the adaptation and immune evasion of a wide range of pathogens. However, the study of their biological function is significantly hampered by the difficulty in controlling their expression in its cellular setting. The genomes of Plasmodium spp. encode a number of different multigene families that are thought to play a critical role for their survival. However, with the exception of the P. falciparum var genes very little is known about the biological roles of any of the other multigene families. Here we report a highly efficient genetic system to study variant antigens in Plasmodium spp. using the Selection Linked Integration method; we are able to activate the expression of a single member of a multigene of our choice using its endogenous promoter. Overall design: 2 clones of the yir transfectants and 1 P. yoelii YM wildtype RNA, each with 3 replicates were extracted and sent for RNA sequencing. Differential Gene expression analysis was performed to compare the gene expression between the wildtype and the transfected parasites.