The Road from Independence to Parasitism

Project Summary: Chromera velia is a photosynthetic, free-living algae that is closely related to apicomplexans, which are a phylum of intracellular parasites responsible for many devastating diseases, including malaria, cryptosporidiosis, and toxoplasmosis. With molecular and cellular landmarks that are clearly related to but distinguishable from those found in apicomplexan parasites, Chromera provides a fantastic opportunity to investigate the evolutionary origin of structures and processes integral to intracellular parasitism. However, tools for defining localization and functions of gene products do not exist for Chromera, which creates a major bottleneck for exploring its biology. We propose to overcome these hurdles. Specifically, we will establish a molecular map of the subcellular structures in Chromera, focusing on identifying structures related to those known to be important for apicomplexan infection of host cells (Aim 1). In parallel, we will develop transformation tools that will enable function analysis in Chromera (Aim 2). Our work will yield fundamental insights into the evolution of aspects of cellular physiology essential for the intracellular parasitic life-style of the apicomplexans. It will also develop for the community molecular genetic and cell biology tools that will synergize evolutionary cell biology research for apicomplexans.