title: Ovate family protein1 interaction with BLH3 regulates transition timing from vegetative to reproductive phase in Arabidopsis.
abstract: Three-Amino-acid-Loop-Extension(TALE) homeodomain transcription factor BLH3 regulates timing of transition from vegetative to reproductive phase. Previous preliminary results obtained using large-scale yeast two-hybrids indicate that BLH3 protein possibly interact with Ovate Family Proteins(OFPs) transcription co-regulators. Nevertheless, it is uncertain whether OFP1-BLH3 complex is involved in regulation of timing of transition from vegetative to reproductive phase in Arabidopsis. The interaction between BLH3 and OFP1 was re-tested and verified by a yeast two-hybrid system. We found that the BLH3-OFP1 interaction was mainly mediated through the BLH3 homeodomain. Meanwhile, this interaction was further confirmed by bimolecular fluorescence complementation (BiFC) in vivo. Further, by establishing protoplast transient expression, we discovered that BLH3 acts as a transcriptional activator, whereas OFP1 functioned as a repressor. The interactions between OFP1 and BLH3 can reduce BLH3 transcriptional activity. The ofp1 mutant lines and blh3 mutant lines, OFP1 overexpress lines and BLH3 overexpress lines can both influence timing of transition from vegetative to reproductive phase. Furthermore, 35s:OFP1/blh3 plants exhibited flowering and leaf quantity similar to that of the wild-type controls. 35s:BLH3/ofp1 plants flowered earlier and had less leaves than wild-type controls, indicating that OFP1 protein might depend partially on BLH3 in its function to regulate the timing of transition from vegetative to reproductive phase. These results support our assumption that, by interacting with OFP1, BLH3 forms a functional protein complex that controls timing of progression from vegetative to reproductive phase, and OFP1 might negatively regulate BLH3 or the BLH-KNOX complex, an important interaction for sustaining the normal transition from vegetative to reproductive phase.
authors.affiliation: College of Life Science, Northeast Agricultural University, Harbin, 150030, China; Heilongjiang Academy of Agricultural Sciences, Harbin, 150086, China.
authors.forename: Liguo
authors.initials: L
authors.lastname: Zhang
authors.affiliation: College of Mathematics and Information Sciences of Guangxi University, Nanning, 530004, China.
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Zhang
authors.affiliation: College of Life Science, Northeast Agricultural University, Harbin, 150030, China.
authors.forename: Hanxun
authors.initials: H
authors.lastname: Ju
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
authors.forename: Jingui
authors.initials: J
authors.lastname: Chen
authors.affiliation: College of Life Science, Northeast Normal University, Changcun, 130024, China.
authors.forename: Shucai
authors.initials: S
authors.lastname: Wang
authors.affiliation: College of Life Science, Northeast Agricultural University, Harbin, 150030, China.
authors.forename: Hemeng
authors.initials: H
authors.lastname: Wang
authors.affiliation: Heilongjiang Academy of Agricultural Sciences, Harbin, 150086, China.
authors.forename: Yuanling
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: College of Life Science, Northeast Agricultural University, Harbin, 150030, China. Electronic address: yingchangnew@163.com.
authors.forename: Ying
authors.initials: Y
authors.lastname: Chang
mesh_terms: D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D018398:Homeodomain Proteins / Q000378:metabolism*; D012097:Repressor Proteins / Q000378:metabolism*; D012098:Reproduction / Q000502:physiology*; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; C544136:BLH3 protein, Arabidopsis; D018398:Homeodomain Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; C523451:ovate family protein 1, Arabidopsis
keywords: Arabidopsis; BLH3; OFP1; Protein–protein interaction; Vegetative to reproductive phase