Figure 4. In organello trans-splicing after electroporation of nad1e recombinant vectors.

(A) The four transcription units required to assemble the nad1 mRNA in wheat mitochondria [21] are indicated in the upper part of panel A (nad1 exons a, b, c, d, and e are represented by boxes). The four chimeric nad1e transgene constructs, Mat1 containing all the 3′-half intron 4 (3′ nad1-I4) and the nad1e exon, Dx1 containing only the maturase domain (Dx) from the mat-r ORF were linked to the inverted repeat (double stem-loop) from the non coding region of wheat apocytochrome b gene (Ir-cob). These constructs were fused to the cytochrome oxidase subunit 2 (cox2) promoter to obtain coxMat1 and cox2Dx1 recombinant vectors. The arrows signal the specific exon and cob primers used in electroporation trans-splicing analyses. (B) Agarose gel electrophoresis of RT-PCR products obtained with the primer cob combined with primers located either in exons nad1b (Pb) or nad1c (Pc). The position of the PCR primers is indicated by arrows. M, molecular weight marker. The different constructs differ on upstream sequences from nad1e exon.