Figure 1.
Primer extension analysis of the 5′ UTR of psbA mRNA in C. reinhardtii. Two principal extension products are observed for the psbA 5′ UTR, one terminating 36 nt upstream of the start codon (−36) and another terminating 90 nt upstream of the start codon (−90). Primer extension of psbA from hf261, a nuclear mutant in which only the 90-nt 5′ UTR of the psbA mRNA is observed, was carried out in the presence of ddATP (U track) to identify the exact cleavage site.