Transcriptional profiling of the Arabidopsis embryo.
We have used laser-capture microdissection to isolate RNA from discrete tissues of globular, heart, and torpedo stage embryos of Arabidopsis (Arabidopsis thaliana). This was amplified and analyzed by DNA microarray using the Affymetrix ATH1 GeneChip, representing approximately 22,800 Arabidopsis genes. Cluster analysis showed that spatial differences in gene expression were less significant than temporal differences. Time course analysis reveals the dynamics and complexity of gene expression in both apical and basal domains of the developing embryo, with several classes of synexpressed genes identifiable. The transition from globular to heart stage is associated in particular with an up-regulation of genes involved in cell cycle control, transcriptional regulation, and energetics and metabolism. The transition from heart to torpedo stage is associated with a repression of cell cycle genes and an up-regulation of genes encoding storage proteins, and pathways of cell growth, energy, and metabolism. The torpedo stage embryo shows strong functional differentiation in the root and cotyledon, as inferred from the classes of genes expressed in these tissues. The time course of expression of the essential EMBRYO-DEFECTIVE genes shows that most are expressed at unchanging levels across all stages of embryogenesis. We show how identified genes can be used to generate cell type-specific markers and promoter activities for future application in cell biology.
Spencer
Matthew W B
MW
Integrative Cell Biology Laboratory, School of Biological and Biomedical Sciences, Durham University, Durham DH1 3LE, United Kingdom.
Casson
Stuart A
SA
Lindsey
Keith
K
D017360:Arabidopsis / Q000196:embryology* / Q000235:genetics*; D019295:Computational Biology; D018548:Cotyledon / Q000378:metabolism; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D018517:Plant Roots / Q000378:metabolism; D036226:Seedlings / Q000378:metabolism; D012639:Seeds / Q000235:genetics; D013997:Time Factors; D014158:Transcription, Genetic / Q000235:genetics*