Figure 1.

Characterization of Atss3 mutations. A, Gene map. The scaled linear map depicts the 14 exons as boxes and the 13 introns as lines between the boxes. The positions of the translational start and stop codons in exons 1 and 14, respectively, are noted. The locations of specific PCR primer sequences are noted, as well as the locations of the two T-DNA insertions in the gene (insertions are not drawn to scale). B, Analysis of AtSS3 5′-end transcripts. Control genomic DNA from wild-type leaves (lane 1) was amplified by PCR and total leaf RNA from Atss3-1 and Atss3-2 mutant plants (lanes 2 and 3, respectively) was amplified by RT-PCR using the gene-specific primers SS3-U2 and SS3-L1. C, Analysis of transcripts from the Atss3-1 mutant. Total RNA from leaves of wild-type plants (lane 1) and Atss3-1 plants (lanes 2 and 3) was amplified by RT-PCR. Primer pairs are SS3-TU1 and SS3-TL1 (lanes 1 and 3). Arabidopsis SSII gene-specific primers SS2-RP1 and SS2-LP1 served as a positive control (lane 2). D, Analysis of transcripts from the Atss3-2 mutant. Total RNA from leaves of wild-type plants (lane 1) and Atss3-2 plants (lanes 2 and 3) was amplified by RT-PCR. Primer pairs were SS3-RP2 and SS3-LP2 (lanes 1 and 3) or Arabidopsis SSII gene-specific primers SS2-RP2 and SS2-LP2 as a positive control (lane 2). E, Analysis of SSIII protein accumulation. Total soluble leaf extracts from wild-type, Atss3-1, and Atss3-2 plants were separated by SDS-PAGE and probed in immunoblot analysis with α-AtSSIII monoclonal antibody.