title: Endomembrane trafficking protein SEC24A regulates cell size patterning in Arabidopsis.
abstract: Size is a critical property of a cell, but how it is determined is still not well understood. The sepal epidermis of Arabidopsis (Arabidopsis thaliana) contains cells with a diversity of sizes ranging from giant cells to small cells. Giant cells have undergone endoreduplication, a specialized cell cycle in which cells replicate their DNA but fail to divide, becoming polyploid and enlarged. Through forward genetics, we have identified a new mutant with ectopic giant cells covering the sepal epidermis. Surprisingly, the mutated gene, SEC24A, encodes a coat protein complex II vesicle coat subunit involved in endoplasmic reticulum-to-Golgi trafficking in the early secretory pathway. We show that the ectopic giant cells of sec24a-2 are highly endoreduplicated and that their formation requires the activity of giant cell pathway genes LOSS OF GIANT CELLS FROM ORGANS, DEFECTIVE KERNEL1, and Arabidopsis CRINKLY4. In contrast to other trafficking mutants, cytokinesis appears to occur normally in sec24a-2. Our study reveals an unexpected yet specific role of SEC24A in endoreduplication and cell size patterning in the Arabidopsis sepal.
authors.affiliation: Weill Institute for Cell and Molecular Biology and School of Integrative Plant Science, Section of Plant Biology, Cornell University, Ithaca, New York 14853.
authors.forename: Xian
authors.identifier: http://orcid.org/0000-0002-9879-099X
authors.initials: X
authors.lastname: Qu
authors.affiliation: Weill Institute for Cell and Molecular Biology and School of Integrative Plant Science, Section of Plant Biology, Cornell University, Ithaca, New York 14853.
authors.forename: Prerana Rao
authors.initials: PR
authors.lastname: Chatty
authors.affiliation: Weill Institute for Cell and Molecular Biology and School of Integrative Plant Science, Section of Plant Biology, Cornell University, Ithaca, New York 14853 ahr75@cornell.edu.
authors.forename: Adrienne H K
authors.identifier: http://orcid.org/0000-0001-6685-2984
authors.initials: AH
authors.lastname: Roeder
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics* / Q000254:growth & development; D002453:Cell Cycle; D048429:Cell Size; D048749:Cytokinesis; D042963:Electron Transport Complex II / Q000235:genetics / Q000378:metabolism; D062951:Endoreduplication; D015726:Giant Cells; D006056:Golgi Apparatus / Q000378:metabolism; D019441:Plant Epidermis / Q000166:cytology / Q000235:genetics / Q000254:growth & development; D011123:Polyploidy; D021122:Protein Subunits; D021381:Protein Transport; D055571:Secretory Pathway
chemical_list: D021122:Protein Subunits; D042963:Electron Transport Complex II