Invasive forms of apicomplexan parasites contain secretory organelles called rhoptries that are essential for entry into host cells. We present a detailed characterization of an unusual rhoptry protein of the human malaria parasite Plasmodium falciparum, the rhoptryassociated membrane antigen (RAMA) that appears to have roles in both rhoptry biogenesis and host cell invasion. RAMA is synthesized as a 170-kDa protein in early trophozoites, several hours before rhoptry formation and is transiently localized within the endoplasmic reticulum and Golgi within lipid-rich microdomains. Regions of the Golgi membrane containing RAMA bud to form vesicles that later mature into rhoptries in a process that is inhibitable by brefeldin A. Other rhoptry proteins such as RhopH3 and RAP1 are found in close apposition with RAMA suggesting direct protein-protein interactions. We suggest that RAMA is involved in trafficking of these proteins into rhoptries. In rhoptries, RAMA is proteolytically processed to give a 60-kDa form that is anchored in the inner face of the rhoptry membrane by means of the glycosylphosphatidylinositol anchor. The p60 RAMA form is discharged from the rhoptries of free merozoites and binds to the red blood cell membrane by its most C-terminal region. In early ring stages RAMA is found in association with the parasitophorous vacuole.Plasmodium falciparum malaria is one of the most important infectious diseases of humans, accounting for ϳ2 million deaths each year. The stages of the parasite that grow and multiply in red blood cells (RBCs) 1 cause all the pathological effects associated with the disease, and accordingly invasion of red blood cells is one of the most important steps in the parasite life cycle. Three sets of secretory organelles, the rhoptries, micronemes, and dense granules are involved in and are essential for the invasion process. The understanding of the role of these organelles provides important knowledge about the basic biology of malaria and potential therapeutical targets.Rhoptries of Plasmodium parasites are paired club-shaped organelles located at the apical end of merozoites, the form of the parasite that invades RBCs. Following the attachment of merozoites to the RBC surface, rhoptries discharge their contents onto the RBC membrane (1). Rhoptry organelles disappear after internalization of merozoites and thus are formed de novo with each erythrocytic cycle. Rhoptry formation occurs late in the erythrocytic stages of the parasite, and elucidation of rhoptry biogenesis of malaria parasites has been hindered by the lack of early organelle markers. Most of our knowledge is based on microscopic examinations, which suggest that rhoptry biogenesis follows the secretory pathway route, with rhoptry organelles being formed by sequential fusion of post-Golgi vesicles (2, 3), although why particular vesicles are selected is unclear.Rhoptry contents include both protein and lipid components, which assemble to form membrane-like structures. Protein constituents of the rhoptry contents are stil...

Mouse models play a key role in the understanding gene function, human development and disease. In 2007, the Australian Government provided funding to establish the Monash University embryonic stem cell-to-mouse (ES2M) facility. This was part of the broader Australian Phenomics Network, a national infrastructure initiative aimed at maximising access to global resources for understanding gene function in the mouse. The remit of the ES2M facility is to provide subsidised access for Australian biomedical researchers to the ES cell resources available from the International Knockout Mouse Consortium (IKMC). The stated aim of the IKMC is to generate a genetically modified mouse ES cell line for all of the ~23,000 genes in the mouse genome. The principal function of the Monash University ES2M service is to import genetically modified ES cells into Australia and to convert them into live mice with the potential to study human disease. Through advantages of economy of scale and established relationships with ES cell repositories worldwide, we have created over 110 germline mouse strains sourced from all of the major ES providers worldwide. We comment on our experience in generating these mouse lines; providing a snapshot of a "clients" perspective of using the IKMC resource and one which we hope will serve as a guide to other institutions or organisations contemplating establishing a similar centralised service.

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