title: BiP3 supports the early stages of female gametogenesis in the absence of BiP1 and BiP2 in Arabidopsis thaliana.
abstract: Immunoglobulin binding protein (BiP) is an essential heat shock protein 70 (Hsp70) in the endoplasmic reticulum (ER) that functions in various processes including protein translocation, protein folding and quality control. Arabidopsis thaliana harbors ubiquitously expressed genes BIP1 and BIP2, as well as BIP3, which is induced only by ER stress. Recently, we reported that these BIP genes are expressed in male gametophytes and cooperate with each other to support male gametogenesis and pollen competitiveness. Here, we report that the BIP genes cooperate to support female gametogenesis. As reported previously, the bip1 bip2 double mutation causes defects in the fusion of polar nuclei during female gametogenesis. By contrast, the bip triple mutant female gametophytes exhibited defects during the early stages of female gametophyte development, which suggests that BIP3 supports the early stages of female gametophyte development, but not polar nuclear fusion, in the absence of BiP1 and BiP2.
authors.affiliation: a Department of Chemistry ; Graduate School of Science; Nagoya University ; Chikusa-ku, Nagoya , Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Maruyama
authors.forename: Toshiya
authors.initials: T
authors.lastname: Endo
authors.forename: Shuh-ichi
authors.initials: S
authors.lastname: Nishikawa
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D005718:Gametogenesis / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018832:Molecular Chaperones / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D056771:Ovule / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C585258:BiP1 protein, Arabidopsis; C585259:BiP2 protein, Arabidopsis; C585260:BiP3 protein, Arabidopsis; D018832:Molecular Chaperones
keywords: Arabidopsis thaliana; BiP; BiP, immunoglobulin binding protein; CLSM, confocal laser-scanning microscopy; ER, endoplasmic reticulum; GUS, β-glucuronidase; Hsp70; Hsp70, heat shock protein 70; central cell; female gametophyte