Figure 2.

Poly(A) Status of Representative Mitochondrial mRNAs from Patient and Control Samples Available

RNA (2.5 μg) from each individual was ligated to linker and subjected to the mitochondrial poly(A) tail-length assay as described in Temperley et al.⁷ Radiolabeled products were separated through a 10% denaturing polyacrylamide gel, and lengths were calculated by comparison against size markers (P³² end-labeled synthetic oligomers of 20 and 75 nt). Oligoadenylated (<10 nt extension from processed transcript) or polyadenylated (35–50 nt extension RNA14; 29–50 nt MTCO1) species were quantified following densitometric scans (ImageQuant software). Lane 1 denotes the mother, lane 2 denotes the father, and lanes 3–6 denote the affected children. The following abbreviations are used: H, HEK293T control cell line; C1 and C2, negative amplification controls from the first and second rounds of PCR; M, size marker; F, control fibroblast cell line. Top: MTCO1 transcript; bottom: RNA14 transcript.