Experimentally inducible gametocytogenesis: a new tool to uncover the early stages of commitment in P. berghei

Plasmodium, the causative agent of malaria, has a complex life cycle requiring a mammalian host and a mosquito vector. Its cyclic infection of red blood cells gives rise to the characteristic fevers and resulting anaemia associated with the disease. Many drug intervention strategies target this, the asexual blood cycle. Little is known about the underlying processes governing the differentiation from this cycle to the sexual stage, the gametocyte, which is uniquely able to transmit through the mosquito to new hosts. In this work we have developed a novel conditional system to build on existing knowledge about the trigger for sexual commitment (ap2-g) to control and expand commitment to gametocytogenesis in the rodent malaria model, Plasmodium berghei. We have characterised the effect of controlling and increasing expression of this initiating transcription factor on asexual and gametocyte development in an effort to obtain an over representation of biologically relevant gametocytes. Using this novel system we initiated an untargeted transcriptomics study to uncover novel factors involved in the process of commitment and other gametocyte specific roles such as gender assignation, sex specific components and overall gametocyte development. From the pilot data obtained from this transcriptomics we identified and screened 40 candidates potentially specifically involved in gametocyte biology. Five of these candidates have been investigated further to uncover novel roles in the early stages of commitment or development (2 gametocyte non-producers), male specific development (1 male non-producer and 1 which seems to effect development) and potentially female specific development (1 in vivo female non-producer). Using the data generated in this study we hope further work can be completed to characterise many aspects of commitment to gametocytogenesis and the processes involved in downstream events required for successful transmission