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Fig. 1. Identification of two GRASP populations in P. falciparum. (A) Northern blot analysis using total RNA of wild-type parasites. A P32 labelled grasp-specific probe detects two transcripts of approximately 3.8 kb and 4 kb. (B) RT-PCR analysis. Two PCR products with a size difference of approximately 150 bp are amplified on cDNA (lane 1) using grasp-specific oligonucleotides. Genomic DNA (gDNA) was used as a positive control (lane 2). To exclude non-specific amplification reactions without template were run as negative controls (lanes 3 and 6). To exclude contaminations of the cDNA preparation with gDNA, erd2-specific oligonucleotides were used (lane 4-6). Consistent with the two-intron structure of the erd2 gene (PF13_0280), a size difference is visible between cDNA (660 bp, lane 5) and gDNA (960 bp, lane 6). (C) Detection of two GRASP proteins in parasite extract. Maximum separation of parasite proteins and subsequent western blotting with GRASP-specific antibodies reveal two translation products of 
70 kDa. (D) Schematic representation of the genomic grasp gene and transcript heterogeneity. (Top) Exon 1 (red) encompasses 33 bp and is separated by a 148 bp intron from exon 2 (grey, 1689 bp). The intron possesses a putative start ATG and 63 bp ORF (yellow) in-frame with exon 2. (Middle and bottom) RT-PCR products were cloned and sequenced. Two different cDNA populations were identified and named cDNA grasp1 and cDNA grasp2, representing a spliced and unspliced version of the grasp gene. The deduced N-terminal amino acid sequence of GRASP2 is displayed in one-letter code in yellow and grey. Vertical line represents stop codons within the intron. Relative positions of oligonucleotides used in RT-PCR are presented as red and grey bars.
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