Protein-RNA interactions important for Plasmodium transmission

After successfully transmitting, they find themselves in a hostile environment that they must exit as quickly as possible or face being digested in the mosquito midgut (gametocytes) or being targeted by antibodies and phagocytes (sporozoites). Because of this, the transmission stages rely heavily on post-transcriptional gene regulation [1], and though this is an energetically costly approach [2], it allows for the required rapid translational responses to environmental changes. While initial evidence for translational repression was seen in targeted studies of individual mRNAs such as p25 and p28 [20, 21] and of the DOZI RNA helicase (Development of Zygote Inhibited; an ortholog of DDX6, Dhh1) in gametocytes [22], evidence for the widespread use of translational repression in both transmission stages is now available from comparative transcriptomic and proteomic studies in gametocytes [23] and sporozoites [24–26]. [...]the deletion of sap1 in either P. yoelii or P. berghei results in greatly reduced UIS transcript abundance, including uis3 and uis4, and pysap1− parasites do not express UIS3 or UIS4 proteins in liver stage parasites when they are required [29–32]. [...]global and specific translational repression are intertwined in sporozoites, as the mRNA of the UIS2 phosphatase responsible for relieving global translational repression via eIF2α dephosphorylation is regulated by PUF2, thus allowing a stepwise and controlled program of development [17, 37].