from gene to protein. A). The new surf4.1 gene structure, showing three exons separated by two introns. Previously the gene was annotated as two genes (PFD0100c and PFD0105c). Using the new structure, with the two genes combined, the protein structure of SURFIN4.1 is estimated to be a 258.3 kDa protein. B). PCR with Sintra4.1F/R primers amplified the intergenic region separating the two genes which make up surf4.1 (PFD0105c and PFD0100c). PCR on cDNA shows presence of transcript in 3D7AH1, 3D7S8, FCR3, FCR3S1.2, 7G8, and TM180 parasite strains. + and - indicate cDNA treated with reverse transcriptase (+) and one not treated with reverse transcriptase (-) respectively. C). Northern blot on 3D7S8, 10 hrs, 20 hrs, 30 hrs and 40 hrs RNA with surf4.1 specific probe. A band of an approximately 7 kb is observed from RNA extracted at 40 h post invasion. The surf4.1 RNA has an open reading frame with a spliced size of 6471 bp. D). Immunoblot on whole parasite cultures of 3D7S8 and FCR3 from 40 hrs+ probed with rabbit anti-SURFIN4.1 purified IgG show a band above 250 kDa confirming that SURFIN4.1 is a full protein encoded by a complete surf4.1 gene.surf 4.1 gene encodes a protein estimated at 258.3 kDa.