Fig. 4: Identification of putative GRP20 homologues among plants.
a, The alignment of NLS (residue 12 to 25, red box), the putative RBD (residue 90 to 114, blue box) and highly disorder region (residue 119 to 153, green box) in GRP20 homologues from 15 angiosperm species, including 9 eudicots (in the top clade of the tree), 4 monocots (in the second clade), water lily (Nymphaea colorata) and Amborella (A. trichopoda, sister to other angiosperms). The positively charged amino acids, the R, K and H region (residue 12 to 17), in NLS are highlighted in light red. The residues in GRP20 RBD predicted to bind RNA are indicated with asterisks above the GRP20 amino acid sequence: 103W, 105Y, 106K, 107K, 110G and 111R. Specifically, 103W, 105Y, 106K and 107K (red asterisks) were altered in a mutant construct to test for RNA binding, as shown in Fig. 7 and Extended Data Fig. 8. The disorder confidence scores along HDRs and whether HDRs can undergo condensation formation of putative GRP20 homologues are shown by Vmodel and βmodel (β-turn propensity). The ParSe program was used in this prediction. Vmodel < 0.56 and βmodel > 0.9 indicate that the domain is intrinsically disordered and prone to undergo condensation formation or fold to a stable conformation. b,c, The heat maps of copy number with affected micro exons in grp20 flowers (b) and leaves (c) among 13 angiosperms (Arabidopsis to Amborella). The orthogroups including MADS-box genes and AP2 family genes (including nearly all floral homeotic genes), cell cyclin genes (NOT9B, CYCH;1 and Rcd1L), transcription factors (homeodomain-like gene GT-1 and homeobox gene ATML1), epigenetic regulators (H3K4 methylation reader ING2, chromatin remodeler BSH and histone methyltransferase), proteosome-degradation genes (MATH-BTB domain genes BPM1, BPM2 and BPM3), acclimation of photosynthesis to environment gene APE1 and other essential genes are indicated in the right panel of the flower heat map. Orthogroups including transcription factors (MADS-box gene AGL42), epigenetic regulators (NAP1;2), protein ubiquitination genes (RING/U-box genes), ABA responsive genes (ERA1), protein chaperons (DnaJ genes), splicing factors (SR33 and SR1) and protein kinases are indicated in the right panel of the leaf heat map.
