Figure 3.

Novel, ‘long’ organellar sRNAs detected in mitochondria and plastids. (A) Two mitochondrial cosRNAs, cox1 3′ and rps4 5′, detected by RNA gel blot analysis (upper panel). Total RNA (10 μg), low-molecular-weight (LMW) RNA and high-molecular-weight (HMW) RNA were run on a denaturing polyacrylamide gel and detected using ³²P-end-labeled oligonucleotide probes after transfer to a nylon membrane. Hybridization signals of the expected size are marked by arrowheads. The asterisk marks a potential 5′-extended form of the cosRNA. sRNA coverage for the respective genome regions is shown below the RNA gel blot images. The cox1 3′-end and rps4 5′-end (47), are indicated by arrows. The annotated rps4 start codon is shown in bold and shaded. A potential alternate start codon at a conserved position is underlined. (B) sRNA coverage for two newly identified cosRNAs (indicated by arrows) upstream of rpoC1 and downstream of rps7 is shown on the left. The cosRNAs were detected by RNA gel blot analysis (show on right). Total RNA (10 μg) from 7-, 14- and 42-day-old plants was separated on denaturing polyacrylamide gels, and cosRNAs were detected as described in (A). Ethidium bromide staining of the gel before transfer, shown below the radiographs, served as a control for loading differences.