title: Phosphorylation of SPOROCYTELESS/NOZZLE by the MPK3/6 Kinase Is Required for Anther Development.
abstract: Germ cells are indispensable carriers of genetic information from one generation to the next. In contrast to the well-understood process in animals, information on the mechanism of germ cell initiation in plants is very limited.SPOROCYTELESS/NOZZLEwas previously identified as an essential regulator of diploid germ cell (archesporial cell) differentiation in the stamens and ovules of Arabidopsis (Arabidopsis thaliana). AlthoughSPOROCYTELESS(SPL) transcription is activated by the floral organ identity regulator AGAMOUS and epigenetically regulated by SET DOMAIN GROUP2, little is known about the regulation of the SPL protein. Here, we report that the protein kinases MPK3 and MPK6 can both interact with SPL in vitro and in vivo and can phosphorylate the SPL protein in vitro. In addition, phosphorylation of the SPL protein by MPK3/6 is required for SPL function in the Arabidopsis anther, as measured by its effect on archesporial cell differentiation. We further demonstrate that phosphorylation enhances SPL protein stability. This work not only uncovers the importance of SPL phosphorylation for its regulatory role in Arabidopsis anther development, but also supports the hypothesis that the regulation of precise spatiotemporal patterning of germ cell initiation and that differentiation is achieved progressively through multiple levels of regulation, including transcriptional and posttranslational modification.
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China (F.Z., Y.-F.Z., T.Z., R.S., J.-Y.Y., Z.-H.X., S.-N.B.).|The National Center of Plant Gene Research, Beijing 100871, China (F.Z., S.-N.B.).|College of Biological Sciences, China Agricultural University, Beijing 100081, China (Y.L., D.-T.R.); and.|State Key Laboratory of Genetic Engineering and Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai 200438, China (H.M.).
authors.forename: Feng
authors.identifier: 0000-0001-5180-2095
authors.initials: F
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China (F.Z., Y.-F.Z., T.Z., R.S., J.-Y.Y., Z.-H.X., S.-N.B.).|The National Center of Plant Gene Research, Beijing 100871, China (F.Z., S.-N.B.).|College of Biological Sciences, China Agricultural University, Beijing 100081, China (Y.L., D.-T.R.); and.|State Key Laboratory of Genetic Engineering and Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai 200438, China (H.M.).
authors.forename: Ya-Feng
authors.identifier: 0000-0002-2101-3797
authors.initials: YF
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China (F.Z., Y.-F.Z., T.Z., R.S., J.-Y.Y., Z.-H.X., S.-N.B.).|The National Center of Plant Gene Research, Beijing 100871, China (F.Z., S.-N.B.).|College of Biological Sciences, China Agricultural University, Beijing 100081, China (Y.L., D.-T.R.); and.|State Key Laboratory of Genetic Engineering and Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai 200438, China (H.M.).
authors.forename: Ting
authors.initials: T
authors.lastname: Zeng
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China (F.Z., Y.-F.Z., T.Z., R.S., J.-Y.Y., Z.-H.X., S.-N.B.).|The National Center of Plant Gene Research, Beijing 100871, China (F.Z., S.-N.B.).|College of Biological Sciences, China Agricultural University, Beijing 100081, China (Y.L., D.-T.R.); and.|State Key Laboratory of Genetic Engineering and Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai 200438, China (H.M.).
authors.forename: Rui
authors.identifier: 0000-0001-6599-0488
authors.initials: R
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China (F.Z., Y.-F.Z., T.Z., R.S., J.-Y.Y., Z.-H.X., S.-N.B.).|The National Center of Plant Gene Research, Beijing 100871, China (F.Z., S.-N.B.).|College of Biological Sciences, China Agricultural University, Beijing 100081, China (Y.L., D.-T.R.); and.|State Key Laboratory of Genetic Engineering and Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai 200438, China (H.M.).
authors.forename: Ji-Yuan
authors.identifier: 0000-0003-0185-1133
authors.initials: JY
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China (F.Z., Y.-F.Z., T.Z., R.S., J.-Y.Y., Z.-H.X., S.-N.B.).|The National Center of Plant Gene Research, Beijing 100871, China (F.Z., S.-N.B.).|College of Biological Sciences, China Agricultural University, Beijing 100081, China (Y.L., D.-T.R.); and.|State Key Laboratory of Genetic Engineering and Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai 200438, China (H.M.).
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China (F.Z., Y.-F.Z., T.Z., R.S., J.-Y.Y., Z.-H.X., S.-N.B.).|The National Center of Plant Gene Research, Beijing 100871, China (F.Z., S.-N.B.).|College of Biological Sciences, China Agricultural University, Beijing 100081, China (Y.L., D.-T.R.); and.|State Key Laboratory of Genetic Engineering and Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai 200438, China (H.M.).
authors.forename: Dong-Tao
authors.identifier: 0000-0003-1031-7071
authors.initials: DT
authors.lastname: Ren
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China (F.Z., Y.-F.Z., T.Z., R.S., J.-Y.Y., Z.-H.X., S.-N.B.).|The National Center of Plant Gene Research, Beijing 100871, China (F.Z., S.-N.B.).|College of Biological Sciences, China Agricultural University, Beijing 100081, China (Y.L., D.-T.R.); and.|State Key Laboratory of Genetic Engineering and Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai 200438, China (H.M.).
authors.forename: Hong
authors.identifier: 0000-0001-8717-4422
authors.initials: H
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China (F.Z., Y.-F.Z., T.Z., R.S., J.-Y.Y., Z.-H.X., S.-N.B.).|The National Center of Plant Gene Research, Beijing 100871, China (F.Z., S.-N.B.).|College of Biological Sciences, China Agricultural University, Beijing 100081, China (Y.L., D.-T.R.); and.|State Key Laboratory of Genetic Engineering and Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai 200438, China (H.M.).
authors.forename: Zhi-Hong
authors.initials: ZH
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China (F.Z., Y.-F.Z., T.Z., R.S., J.-Y.Y., Z.-H.X., S.-N.B.); shunongb@pku.edu.cn.|The National Center of Plant Gene Research, Beijing 100871, China (F.Z., S.-N.B.); shunongb@pku.edu.cn.|College of Biological Sciences, China Agricultural University, Beijing 100081, China (Y.L., D.-T.R.); and shunongb@pku.edu.cn.|State Key Laboratory of Genetic Engineering and Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai 200438, China (H.M.) shunongb@pku.edu.cn.
authors.forename: Shu-Nong
authors.identifier: 0000-0002-9521-4073
authors.initials: SN
authors.lastname: Bai
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation / Q000235:genetics; D035264:Flowers / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D055993:Germ Cells, Plant / Q000166:cytology / Q000378:metabolism; D007150:Immunohistochemistry; D008856:Microscopy, Fluorescence; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D030821:Plants, Genetically Modified; D011485:Protein Binding; D055550:Protein Stability; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D029681:Arabidopsis Proteins; D009687:Nuclear Proteins; D012097:Repressor Proteins; C416221:SPL protein, Arabidopsis; C458516:AtMPK3 protein, Arabidopsis; C436293:MPK6 protein, Arabidopsis; D020928:Mitogen-Activated Protein Kinases; D020929:Mitogen-Activated Protein Kinase Kinases