Timing mechanism dependent on cell division is invoked by Polycomb eviction in plant stem cells.
Plant floral stem cells divide a limited number of times before they stop and terminally differentiate, but the mechanisms that control this timing remain unclear. The precise temporal induction of the Arabidopsis zinc finger repressor KNUCKLES (KNU) is essential for the coordinated growth and differentiation of floral stem cells. We identify an epigenetic mechanism in which the floral homeotic protein AGAMOUS (AG) induces KNU at ~2 days of delay. AG binding sites colocalize with a Polycomb response element in the KNU upstream region. AG binding to the KNU promoter causes the eviction of the Polycomb group proteins from the locus, leading to cell division-dependent induction. These analyses demonstrate that floral stem cells measure developmental timing by a division-dependent epigenetic timer triggered by Polycomb eviction.
Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Republic of Singapore.
Bo
B
Sun
Liang-Sheng
LS
Looi
Siyi
S
Guo
Zemiao
Z
He
Eng-Seng
ES
Gan
Jiangbo
J
Huang
Yifeng
Y
Xu
Wan-Yi
WY
Wee
Toshiro
T
Ito
D026342:AGAMOUS Protein, Arabidopsis / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division / Q000235:genetics / Q000502:physiology*; D044127:Epigenesis, Genetic; D035264:Flowers / Q000166:cytology / Q000235:genetics / Q000254:growth & development*; D018506:Gene Expression Regulation, Plant; D018519:Meristem / Q000166:cytology*; D008969:Molecular Sequence Data; D030821:Plants, Genetically Modified / Q000166:cytology / Q000254:growth & development; D063146:Polycomb-Group Proteins / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D013234:Stem Cells / Q000166:cytology*; D013997:Time Factors; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism
D026342:AGAMOUS Protein, Arabidopsis; D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D063146:Polycomb-Group Proteins; D015534:Trans-Activators; C491031:knuckles protein, Arabidopsis