Changing a conserved amino acid in R2R3-MYB transcription repressors results in cytoplasmic accumulation and abolishes their repressive activity in Arabidopsis.
Sub-group 4 R2R3-type MYB transcription factors, including MYB3, MYB4, MYB7 and MYB32, act as repressors in phenylpropanoid metabolism. These proteins contain the conserved MYB domain and the ethylene-responsive element binding factor-associated amphiphilic repression (EAR) repression domain. Additionally, MYB4, MYB7 and MYB32 possess a putative zinc-finger domain and a conserved GY/FDFLGL motif in their C-termini. The protein 'sensitive to ABA and drought 2' (SAD2) recognizes the nuclear pore complex, which then transports the SAD2-MYB4 complex into the nucleus. Here, we show that the conserved GY/FDFLGL motif contributes to the interaction between MYB factors and SAD2. The Asp → Asn mutation in the GY/FDFLGL motif abolishes the interaction between MYB transcription factors and SAD2, and therefore they cannot be transported into the nucleus and cannot repress their target genes. We found that MYB4(D261N) loses the capacity to repress expression of the cinnamate 4-hydroxylase (C4H) gene and biosynthesis of sinapoyl malate. Our results indicate conservation among MYB transcription factors in terms of their interaction with SAD2. Therefore, the Asp → Asn mutation may be used to engineer transcription factors.
Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
Meiliang
M
Zhou
Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
Zhanmin
Z
Sun
Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.|School of Life Science, Sichuan Agricultural University, Yaan, 625014, Sichuan, China.
Chenglong
C
Wang
Grassland Science Department, Sichuan Agriculture University, Chengdu, 611130, Sichuan, China.
Xinquan
X
Zhang
Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
Yixiong
Y
Tang
School of Resources and Environment, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.
Xuemei
X
Zhu
School of Life Science, Sichuan Agricultural University, Yaan, 625014, Sichuan, China.
Jirong
J
Shao
Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
Yanmin
Y
Wu
D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D017354:Point Mutation / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics
D029681:Arabidopsis Proteins; D012097:Repressor Proteins
Arabidopsis thaliana; GY/FDFLGL motif; MYB transcription factor; bimolecular fluorescence complementation; phenylpropanoid pathway; point mutation; transcriptional repressor