Figure 4.

Northern blot hybridizations and RT-PCR of P. yoelii yoelii YM RNA, demonstrating differential transcription and splicing of maebl. Poly(A)-enriched RNA of P. yoelii yoelii YM was hybridized with a P. yoelii yoelii YM cDNA clone encoding only the AMA-1-like domains (A) or a probe specific for the 3′ region of maebl encoding the EBP-like region (B). Two transcripts with apparent sizes of 8.0 kb and 5.6 kb were hybridized by the probe to the AMA-1-like encoding region, but the probe to the 3′ region of maebl hybridized only to the 8-kb transcript. This fact demonstrated that only the 8-kb transcript encoded the carboxyl cysteine-rich domain, the transmembrane domain, and the cytoplasmic tail. Transcript sizes are given in kilobases as calculated on the basis of a 0.24- to 9.5-kb RNA ladder. Brightness and contrast were adjusted electronically. (C) RT-PCR demonstrating differential splicing of maebl transcripts. The schema shows the cryptic intron within the region encoding the M2 domain and the oligonucleotide primer positions used for specific amplification. Primer combination 214/278 amplified a product from a transcript lacking the cryptic intron, and primer combination 214/279 amplified a product from a transcript containing the cryptic intron. No amplification could be detected in control reactions without RT (−RT).