Figure 3.

Accumulation of plastid mRNAs in wild-type and plastid rpo gene deletion derivatives. Data are shown for genes carrying only PEP promoters (rbcL), only NEP promoters (accD), or PEP and NEP promoters (clpP, 16S rDNA, atpB) in wild-type, ΔrpoA, ΔrpoB, ΔrpoC1, and ΔrpoC2 leaves. The excess of wild-type over Δrpo intensities (average of the four Δrpo lines) for each probe is given in parentheses. Gel blots were prepared with total leaf RNA (5 μg per lane) from wild-type plants, and in plants transformed with plasmids pGS95 (ΔrpoA), pGS97 (ΔrpoC1), and pGS99 (ΔrpoC2). Upper panels show blots probed for plastid genes. Lower panels show loading controls, obtained by probing the same filters for the cytoplasmic 25S rRNA. The blots were scanned with a phosphor imager (Molecular Dynamics, Sunnyvale, CA). Hybridization signals were quantified with Imagequant software (Molecular Dynamics) and normalized to the 25S rRNA signal.