Kinetic model for the study of gene expression in the developing sea urchin.

We have derived a kinetic model to assist in the study of gene expression for systems in which rapid changes in cell number occur. This kinetic model is based upon development of the sea urchin embryo, and considers changes in the number of cells, the fraction of each cell-cycle spent in mitosis, and the overall rate of transcription. We have applied this kinetic model to the accumulation of actin messenger RNA which occurs early in sea urchin embryogenesis. This analysis demonstrates that the rapid increase in cell number profoundly influences the kinetics of mRNA accumulation, and that failure to take into account the work performed by each cell can lead to significant misinterpretations of data on the expression of specific genes.