Figure 4.

Developmental and age-dependent accumulation of plastid cosRNAs. (A) True leaves of 32-day-old Arabidopsis plants were harvested according to their time of emergence and separated into five samples. Leaves 1 and 2 represent the first emerging leaves. Total RNA (10 μg) was separated on denaturing polyacrylamide gels, and RNA gel blots were performed using ³²P-end-labeled oligonucleotide probes antisense to three cosRNAs representing footprints of the RNA binding proteins CRR2, HCF152 and HCF107. Ethidium bromide staining of the gel before transfer served as a control for equal loading. Sizes of marker oligonucleotides are indicated. (B) Analysis of cosRNAs during leaf aging in cotyledons and first true leaves. The day of harvest after sowing (d) is indicated for each sample. Oligoprobes used are the same as in (A).