FIGURE 2.

Mutations in human β-globin RNA activator of PKR and silencer of PKR activation are associated with β-thalassemia. Structure of the RNA activator of PKR (nucleotides 1–124), determined by in-line probing and mutagenesis, with a key role for helix strands a (green) and b (cyan). Strand a includes the AUG start codon. Position of first splice junction is shown, as is start of exon 2 containing PKR silencer c (red), upon excision of intron 1 but before displacement of strand b by sequence c validated by in-line probing and mutagenesis (see Figure 1B). Nucleotide mutations associated with β-thalassemia in the human gene mutation database (http://www.hgmd.org), are marked by shading in various colors, see text. HBB, human β-globin gene.