A comprehensive gene expression analysis toward the understanding of growth and differentiation of tobacco BY-2 cells

To understand how plant cell changes gene expression during cell division and after termination of cell division, we analyzed the change of gene expression during the growth of tobacco BY-2 cell lines using a cDNA microarray, which contained about 9,200 expression sequence tag fragments and corresponded to about 7,000 genes. We found that log phase cells predominantly expressed DNA/chromosome duplication gene homologs. In addition, many genes for basic transcription and translation machineries, as well as proteasomal genes, were up-regulated at the log phase. About half of the kinesin homolog genes, but not myosin homolog genes, were predominantly expressed at the dividing phase as well; In contrast, stationary phase cells expressed genes for many receptor kinases, signal transduction machineries and transcription factors. Several hundreds of genes showed differential expression after incubation of stationary phase cells with medium containing either salicylic acid or abscisic acid. These findings suggested that BY-2 cells at the stationary phase express genes for perceiving extracellular signals.

为了解植物细胞在细胞分裂期间以及细胞分裂终止后如何改变基因表达，我们利用一种包含约9200个表达序列标签片段且对应约7000个基因的cDNA微阵列，分析了烟草BY - 2细胞系生长过程中基因表达的变化。我们发现对数生长期的细胞主要表达DNA/染色体复制基因同源物。此外，许多参与基础转录和翻译机制的基因以及蛋白酶体基因在对数生长期上调。大约一半的驱动蛋白同源基因（但不是肌球蛋白同源基因）在分裂期也主要表达；相反，静止期细胞表达许多受体激酶、信号转导机制和转录因子的基因。将静止期细胞在含有水杨酸或脱落酸的培养基中培养后，有数百个基因表现出差异表达。这些发现表明，静止期的BY - 2细胞表达用于感知细胞外信号的基因。