Contributions of Individual Amino Acid Residues to the Endogenous CLV3 Function in Shoot Apical Meristem Maintenance in Arabidopsis

• Published in: Molecular plant 2012-03, Vol.5 (2), p.515-523
• Main Authors: Song, Xiu-Fen, Yu, Da-Li, Xu, Ting-Ting, Ren, Shi-Chao, Guo, Peng, Liu, Chun-Ming
• Format: Article
• Language: English
• Subjects: Amino Acid Motifs; amino acid residue; Amino Acid Sequence; Amino Acid Substitution - genetics; Amino Acids - metabolism; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis Proteins - chemistry; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; CLV3; Conserved Sequence - genetics; contribution; Flowers - metabolism; Gene Expression Regulation, Plant; Genetic Complementation Test; Genetics; Homeodomain Proteins - genetics; Homeodomain Proteins - metabolism; Meristem - metabolism; Molecular Sequence Data; peptide; Peptides; Plants, Genetically Modified; Proteins; Real-Time Polymerase Chain Reaction; stem cell maintenance; Structure-Activity Relationship; 天门冬氨酸; 拟南芥; 氨基酸残基; 维护; 职能; 肽类激素; 茎尖分生组织; 转基因植物
• ISSN: 1674-2052; 1752-9867
• DOI: 10.1093/mp/ssr120

As a peptide hormone, CLV3 restricts the stem cell number in shoot apical meristem （SAM） by interacting with CLV1/CLV2/CRN/RPK2 receptor complexes. To elucidate how the function of the CLV3 peptide in SAM maintenance is established at the amino acid （AA） level, alanine substitutions were performed by introducing point mutations to individual residues in the peptide-coding region of CLV3 and its flanking sequences. Constructs carrying such substitutions, expressed under the control of CLV3 regulatory elements, were transformed to the clv3-2 null mutant to evaluate their efficiencies in complementing its defects in SAMs in vivo. These studies showed that aspartate-8, histidine-11, glycine-6, proline-4, arginine-1, and proline-9, arranged in an order of importance, were critical, while threonine-2, valine-3, serine-5, and the previously assigned hydroxylation and arabinosylation residue proline-7 were trivial for the endogenous CLV3 function in SAM maintenance. In contrast, substitutions of flanking residues did not impose much damage on CLV3. Complementation of different alanine-substituted constructs was confirmed by measurements of the sizes of SAMs and the WUS expression levels in transgenic plants. These studies established a complete contribution map of individual residues in the peptide-coding region of CLV3 for its function in SAM, which may help to understand peptide hormones in general.