Fig. 7: RNA consensus motifs, binding of GRP20 to GA-rich consensus and the regulation of micro-exon splicing in floral homeotic genes.
a, An illustration of the micro exons in MADS-box and AP2 family genes. The micro exons and their sizes in MADS-box and AP2 family genes are shown in the table on the left. X indicates the absence of the micro exon. The affected micro exons are highlighted in red in gene structure diagrams on the right. The other micro exons are shown in orange, whereas other exons are shown as open boxes. Illustrations of gene structures, transcripts and reads for these floral homeotic genes and other flower developmental genes are shown in Extended Data Fig. 3. b, The consensus motifs and percentages found in defective transcripts, with ES and ASI defects. ES_C1 and ASI_C1 correspond to RNA probe 1, used for RNA binding. ES_C1 and ASI_C1 are the two most frequent consensuses; ASI, alternatively spliced intron. c, The presence of micro exons in close functional homologues (orthologues) of AP1, AG, AP3 and AP2 in several angiosperms. The number indicates the gene copy in this species. Y and N indicate the presence and absence of micro exons in each copy, respectively. As examples, the gene structures, including micro exons, of AP1 and AP2 homologues are shown in Extended Data Fig. 5h. Am, A. trichopoda; Os, O. sativa; Hv, Hordeum vulgare; Sl, Solanum lycopersicum; At, A. thaliana; Gm, G. max. d, An in vitro EMSA binding experiment using recombinant GRP20 proteins and synthetic consensus P1, as shown in Extended Data Fig. 8a. His–SUMO was used as a negative control. The mutations in the RBD and deletion of RBD were selected based on the predicted RNA-binding ___domain and residues shown in Extended Data Fig. 1.
