title: Distinct gene expression profiles in egg and synergid cells of rice as revealed by cell type-specific microarrays.
abstract: Double fertilization in flowering plants refers to a process in which two sperm cells, carried by the pollen tube, fertilize both the egg and the central cell after their release into a synergid cell of the female gametophyte. The molecular processes by which the female gametophytic cells express their unique functions during fertilization are not well understood. Genes expressed in egg and synergid cells might be important for multiple stages of the plant reproductive process. Here, we profiled genome-wide gene expression in egg and synergid cells in rice (Oryza sativa), a model monocot, using a nonenzymatic cell isolation technique. We found that the expression profiles of the egg and synergid cells were already specified at the micropylar end of the female gametophyte during the short developmental period that comprises the three consecutive mitotic nuclear divisions after megaspore generation. In addition, we identified a large number of genes expressed in the rice egg and synergid cells and characterized these genes using Gene Ontology analysis. The analysis suggested that epigenetic and posttranscriptional regulatory mechanisms are involved in the specification and/or maintenance of these cells. Comparisons between the rice profiles and reported Arabidopsis (Arabidopsis thaliana) profiles revealed that genes enriched in the egg/synergid cell of rice were distinct from those in Arabidopsis.
authors.affiliation: Graduate School of Agricultural and Life Sciences, University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Ohnishi
authors.forename: Hideki
authors.initials: H
authors.lastname: Takanashi
authors.forename: Mirai
authors.initials: M
authors.lastname: Mogi
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Takahashi
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Kikuchi
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yano
authors.forename: Takashi
authors.initials: T
authors.lastname: Okamoto
authors.forename: Masahiro
authors.initials: M
authors.lastname: Fujita
authors.forename: Nori
authors.initials: N
authors.lastname: Kurata
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Tsutsumi
mesh_terms: D019295:Computational Biology; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D020411:Oligonucleotide Array Sequence Analysis; D012275:Oryza / Q000235:genetics*; D056771:Ovule / Q000235:genetics*; D011401:Promoter Regions, Genetic; D018749:RNA, Plant / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D018749:RNA, Plant