Cell-by-cell developmental transition from embryo to postgermination phase revealed by heterochronic gene expression and ER-body formation in Arabidopsis leafy cotyledon mutants.
Cell-by-cell developmental transition from embryo to postgermination phase revealed by heterochronic gene expression and ER-body formation in Arabidopsis leafy cotyledon mutants.
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拟南芥叶状子叶突变体中异时基因表达和 ER 体形成揭示了从胚胎到发芽后阶段的逐个细胞发育转变。
DOI：
10.1093/pcp/pcu139
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发表时间：
2014
影响因子：
4.9
通讯作者：
T.
中科院分区：
文献类型：
--
作者：
Yamamoto;A.;Yoshii;M.;Murase;S.;Fujita;M.;Kurata;N.;Hobo;T.;Kagaya;Y.;Takeda;S. and Hattori;T.
LEC 1、LEC 2、FUS 3和ABI 3（以下统称LEC/ABI 3）是胚成熟所必需的，在抑制胚后发育中具有明显的作用。虽然LEC/ABI 3作为胚胎成熟的正调控因子的作用已被广泛研究，但其在萌发后发育的负调控中的作用尚未被详细探讨。基于基因芯片分析，我们选择PYK 10，它编码内质网（ER）体定位蛋白，作为萌发后发育的分子标记。lec/abi 3胚胎表现出PYK 10的错误表达和“组成型”ER体的形成，这在幼苗期特异性地发展，证实了这些突变体在基因表达和细胞水平上的异时性。PYK 10报告基因在lec 1胚胎中的表达早在球心过渡期就开始了。PYK 10启动子增强的绿色荧光蛋白（EGFP）报告基因表达的起始在发育中的lec/abi 3胚胎和萌发中的野生型幼苗中以随机的、逐个细胞的方式发生。此外，在沿着的细胞堆中经常发现成簇的EGFP阳性细胞，这可能代表了表达状态通过细胞分裂的传递。这些观察结果，连同使用PYK 10-EGFP/PYK 10-CFPdouble reporter转基因系的实验结果和PYK 10染色质中H3 K27 me 3水平的分析，表明表观遗传机制参与了在胚胎发生期间抑制萌发后基因和在向萌发后发育过渡时解除这些基因的抑制。
LEC1,LEC2,FUS3andABI3(collectively abbreviatedLEC/ABI3here) are required for embryo maturation and have apparent roles in repressing post-germinative development.lecmutant embryos exhibit some heterochronic characteristics, as exemplified by the development of true leaf-like cotyledons during embryogenesis. Although the roles of LEC/ABI3 as positive regulators of embryo maturation have been extensively studied, their roles in the negative regulation of post-germinative development have not been explored in detail. Based on microarray analyses, we chosePYK10, which encodes an endoplasmic reticulum (ER)-body-localized protein, as a molecular marker of post-germinative development.lec/abi3embryos exhibitedPYK10misexpression and the formation of ‘constitutive’ ER-bodies, which develop specifically during the seedling stage, confirming the heterochronic nature of these mutants at both the gene expression and cellular levels. ThePYK10reporter expression inlec1embryos started as early as the globular–heart transition stage. The onset ofPYK10promoter–enhanced green fluorescent protein (EGFP) reporter expression occurred in a stochastic, cell-by-cell manner in both developinglec/abi3embryos and germinating wild-type seedlings. Additionally, clustered EGFP-positive cells were frequently found along cell files, probably representing the transmission of the expression state via cell division. These observations, together with the results of the experiments usingPYK10-EGFP/PYK10-CFPdouble reporter transgenic lines and the analyses of H3K27me3 levels in thePYK10chromatin, suggested the involvement of epigenetic mechanisms in repressing post-germinative genes during embryogenesis and derepressing these genes upon the transition to post-germinative development.