Fig. 7. Molecular characterization of HST. (A) Genomic structure. Exons are indicated by boxes. Arrows indicate the position of mutations described in the text. (B) Poly(A)-enriched RNA from leaves, roots and floral buds hybridized with a 5' fragment of the HST cDNA. This blot was stripped and re-hybridized with an actin probe, which served as a loading control. (C) CLUSTAL X 1.81 alignment of the amino acid sequence of HST (AY198396), human Xpo5 (NP_065801) and Msn5p (NP_010622) from S. cerevisiae. Amino acids identical in two or more sequences are highlighted in black; similar amino acids are highlighted in gray.