Retrieving parasite specific liver stage gene products in Plasmodium yoelii infected livers using differential display

Differential display (DD) has been routinely used to identify genes whose e xpression pattern is altered by changes in the cellular environment and/or at different stages of development. Most reports utilizing DD contain conve ntional DD primers that have high guanine and cytosine content and would no t be expected to be optimal for Plasmodium which has approximately 30-40% G + C. In an attempt to accommodate the high adenine and thymidine rich geno me of Plasmodium yoelii, we utilized PCR primers containing 40, 50 and 60% G + C and modified the existing DD technique. Thus 40% G + C appeared to be the most suitable to amplify Plasmodium genome. Gene specific primers were generated from the sequences of selected DD bands amplified using the 40% G + C primers and were used to verify that the DD clones were of parasite o rigin by PCR and sequence alignment. Additional data on five of the selecte d DD clones, designated P2T1L5, P2T1L6, P2T6L11, P2T7L12 and P2T7L13, sugge sted that all are expressed during the P. yoelii liver stage infection. Int erestingly, P2T1L5 is also expressed during the sporozoite stage of the lif e cycle and both P2T1L6 and P2T6L11 are present as blood stage antigens. Th e results of this study suggest that DD incorporating primers with low G C content allows the identification of P. yoelii messages from infected mou se livers. (C) 2000 Elsevier Science B.V. All rights reserved.