comparative transcriptional analysis reveals differential gene expression between asymmetric and symmetric zygotic divisions in tobacco比较转录基因差异表达分析显示非对称和对称的受精卵的分裂之间的烟草.pdfVIP

Comparative Transcriptional Analysis Reveals Differential Gene Expression between Asymmetric and Symmetric Zygotic Divisions in Tobacco Tian-Xiang Hu., Miao Yu., Jie Zhao* State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China Abstract Asymmetric cell divisions occur widely during many developmental processes in plants. In most angiosperms, the first zygotic cell division is asymmetric resulting in two daughter cells of unequal size and with distinct fates. However, the critical molecular mechanisms regulating this division remain unknown. Previously we showed that treatment of tobacco zygotes with beta-glucosyl Yariv (bGlcY) could dramatically alter the first zygotic asymmetric division to produce symmetric two-celled proembryos. In the present study, we isolated zygotes and two-celled asymmetric proembryos in vivo by micromanipulation, and obtained symmetric, two-celled proembryos by in vitro cell cultures. Using suppression-subtractive hybridization (SSH) and macroarray analysis differential gene expression between the zygote and the asymmetric and symmetric two-celled proembryos was investigated. After sequencing of the differentially expressed clones, a total of 1610 EST clones representing 685 non-redundant transcripts were obtained. Gene ontology (GO) term analysis revealed that these transcripts include those involved in physiological processes such as response to stimulus, regulation of gene expression, and localization and formation of anatomical structures. A homology search against known genes from Arabidopsis indicated that some of the above transcripts are involved in asymmetric cell division and embryogenesis. Quantitative real-time PCR confirmed the up