Figure 5

Alternative splicing in P. falciparum . (A) Intron retention in PF3D7_0103200 observed in polysome-associated mRNA at the schizont stage. (B) Differential introns in PF3D7_0601200 in polysomal mRNA as compared to steady-state mRNA, resulting in skipping of exon 1. (C) Validation of alternative splice variants in steady-state mRNA (S) and polysomal mRNA (P) fractions by RT-PCR. A schematic representation of the PCR strategy is shown in the lower parts of (A, B). For PF3D7_0103200 (top), the unspliced transcript variant is exclusively detected in polysomal mRNA. For PF3D7_0601200 (bottom), only a non-annotated splice variant is detected in the polysomal fraction. (D) Retained introns and truncated exon 2 observed in both steady-state and polysome-associated mRNA for PF3D7_0807700. (E) Validation of sequencing results for PF3D7_080770 by cloning of a fragment corresponding to exons 2 to 5 from PF3D7_0807700. Only one out of 12 clones contained the full-length transcript, while the remaining 11 clones encoded truncated versions of the transcript with several combinations of retained intron 3/4 and truncated exon 2.