| Autor: |
Roques M; School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, United Kingdom., Wall RJ; School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, United Kingdom., Douglass AP; School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, United Kingdom., Ramaprasad A; Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia., Ferguson DJ; Nuffield Department of Clinical Laboratory Science, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom., Kaindama ML; School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, United Kingdom., Brusini L; School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, United Kingdom., Joshi N; School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, United Kingdom., Rchiad Z; Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia., Brady D; School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, United Kingdom., Guttery DS; School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, United Kingdom., Wheatley SP; School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, United Kingdom., Yamano H; UCL Cancer Institute, University College London, London, United Kingdom., Holder AA; Mill Hill Laboratory, The Francis Crick Institute, Mill Hill, London, United Kingdom., Pain A; Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia., Wickstead B; School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, United Kingdom., Tewari R; School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, United Kingdom. |
| Abstrakt: |
Cell-cycle progression and cell division in eukaryotes are governed in part by the cyclin family and their regulation of cyclin-dependent kinases (CDKs). Cyclins are very well characterised in model systems such as yeast and human cells, but surprisingly little is known about their number and role in Plasmodium, the unicellular protozoan parasite that causes malaria. Malaria parasite cell division and proliferation differs from that of many eukaryotes. During its life cycle it undergoes two types of mitosis: endomitosis in asexual stages and an extremely rapid mitotic process during male gametogenesis. Both schizogony (producing merozoites) in host liver and red blood cells, and sporogony (producing sporozoites) in the mosquito vector, are endomitotic with repeated nuclear replication, without chromosome condensation, before cell division. The role of specific cyclins during Plasmodium cell proliferation was unknown. We show here that the Plasmodium genome contains only three cyclin genes, representing an unusual repertoire of cyclin classes. Expression and reverse genetic analyses of the single Plant (P)-type cyclin, CYC3, in the rodent malaria parasite, Plasmodium berghei, revealed a cytoplasmic and nuclear location of the GFP-tagged protein throughout the lifecycle. Deletion of cyc3 resulted in defects in size, number and growth of oocysts, with abnormalities in budding and sporozoite formation. Furthermore, global transcript analysis of the cyc3-deleted and wild type parasites at gametocyte and ookinete stages identified differentially expressed genes required for signalling, invasion and oocyst development. Collectively these data suggest that cyc3 modulates oocyst endomitotic development in Plasmodium berghei. |
