An R2R3-type transcription factor gene AtMYB59 regulates root growth and cell cycle progression in Arabidopsis.
MYB proteins play important roles in eukaryotic organisms. In plants, the R1R2R3-type MYB proteins function in cell cycle control. However, whether the R2R3-type MYB protein is also involved in the cell division process remains unknown. Here, we report that an R2R3-type transcription factor gene, AtMYB59, is involved in the regulation of cell cycle progression and root growth. The AtMYB59 protein is localized in the nuclei of onion epidermal cells and has transactivation activity. Expression of AtMYB59 in yeast cells suppresses cell proliferation, and the transformants have more nuclei and higher aneuploid DNA content with longer cells. Mutation in the conserved domain of AtMYB59 abolishes its effects on yeast cell growth. In synchronized Arabidopsis cell suspensions, the AtMYB59 gene is specifically expressed in the S phase during cell cycle progression. Expression and promoter-GUS analysis reveals that the AtMYB59 gene is abundantly expressed in roots. Transgenic plants overexpressing AtMYB59 have shorter roots compared with wild-type plants (Arabidopsis accession Col-0), and around half of the mitotic cells in root tips are at metaphase. Conversely, the null mutant myb59-1 has longer roots and fewer mitotic cells at metaphase than Col, suggesting that AtMYB59 may inhibit root growth by extending the metaphase of mitotic cells. AtMYB59 regulates many downstream genes, including the CYCB1;1 gene, probably through binding to MYB-responsive elements. These results support a role for AtMYB59 in cell cycle regulation and plant root growth.
Mu
Rui-Ling
RL
Plant Gene Research Center, National Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
Cao
Yang-Rong
YR
Liu
Yun-Feng
YF
Lei
Gang
G
Zou
Hong-Feng
HF
Liao
Yong
Y
Wang
Hui-Wen
HW
Zhang
Wan-Ke
WK
Ma
Biao
B
Du
Ji-Zhou
JZ
Yuan
Ming
M
Zhang
Jin-Song
JS
Chen
Shou-Yi
SY
D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002453:Cell Cycle / Q000502:physiology*; D002455:Cell Division / Q000502:physiology; D019926:Cyclin B / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D019697:Onions / Q000235:genetics; D009928:Organ Specificity; D019441:Plant Epidermis / Q000166:cytology / Q000235:genetics; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015003:Yeasts / Q000166:cytology / Q000254:growth & development
D029681:Arabidopsis Proteins; C482738:BOTRYTIS SUSCEPTIBLE1 protein, Arabidopsis; C462528:CycB1 protein, Arabidopsis; D019926:Cyclin B; D014157:Transcription Factors; C550208:myb domain protein 59, Arabidopsis