Figure 3.

OZ2 is a mitochondrial splicing factor. (A) Gene model for nad1. Black boxes (lines) represent exons (introns). Maturation of nad1 necessitates four splicing events, two cis-splicing events (II and IV), and two trans-splicing events (I and III). Arrows indicate the primers used in the qRT-PCR analysis; red arrows indicate the primers used to quantify the amount of unspliced transcripts. (B) qRT-PCR analysis of nad1 transcript species demonstrated that the amount of spliced intron 1 transcript (nad1-ex1ex2) is severely reduced in oz2/oz2/OZ* (around 60 times), while the amount of unspliced precursor (nad1-in1) is slightly higher in oz2/oz2/OZ* than in the wild-type (wt) plants (around 5 times). Splicing of intron 1 is the only splicing defect for nad1 as the other spliced transcripts, nad1-ex2ex3, nad1-ex3ex4, nad1-ex4ex5, exhibit a slight but significant increased amount in oz2 compared to the wild-type plants. The assay was performed on the RNAs from plants shown in Figure 1: three wild-type T1 plants, three oz2/oz2/OZ2* T₁ plants, and one oz2/oz2/OZ2* T₀ plant. Three technical replicates were measured for each data point (*P< 0.05, **P< 0.01, ***P< 0.001, ****P< 0.0001).