Figure 1.

Structure of BRX family genes and proteins in Arabidopsis, poplar, and rice. A, Intron-exon structure of confirmed and predicted BRXL genes in Arabidopsis (AtBRXL), poplar (PtBRXL), and rice (OsBRXL), drawn to scale. Numbers indicate the size of features in nucleotides. If available, 5′ and 3′ untranslated regions are included. Gray boxes indicate exon, untranslated; black boxes indicate exon, coding; white boxes indicate intron. Patterned boxes in OsBRXL3 indicate predicted coding exons, which are, however, missing in the only available cDNA clone for this gene. B, Amino acid alignment of conserved domains in the N terminus of BRXL proteins. Numbers indicate amino acid position for the first and last residue shown. C, As in B, showing alignment of the first BRX repeat domain. D, As in B, showing alignment of the second BRX repeat domain.