A green cell-cycle transcriptome

The transcriptional regulation of the cell cycle in plants has features in common with other higher eukaryotes, as well as potential plant-specific pathways. In the Early Edition of the Proceedings of the National Academy of Sciences Breyne et al. describe a genome-wide expression analysis of cell-cycle-modulated genes in the tobacco Bright Yellow-2 (BY2) cell line. They applied a cDNA-amplified fragment length polymorphism (AFLP) technology to overcome the limitations imposed by the lack of extensive genomic and microarray resources for tobacco. Analysis of about 10,000 transcript tags revealed that 10% of transcripts were periodically expressed. Hierarchical clustering identified clusters associated with the phases of the cell cycle. About one third of the tags are homologous to genes of known function. Breyne et al. identified genes encoding cyclins, kinases and phosphatases previously associated with cell-cycle progression, as well as novel genes that may provide insights into the regulation of the plant cell cycle.