KINETICS OF METALLOTHIONEIN GENE INDUCTION BY CADMIUM IN HUMAN-LYMPHOCYTES

Induction of gene transcription is a complex process involving a diver se set of transcription factors and regulatory steps. We have taken a kinetic approach to analysis of metallothionein gene induction in huma n peripheral blood lymphocytes. By repeated measurements of MT mRNA af ter incubation of cells in vitro with CdCl2, we were able to determine individual-specific time related constants. The kinetics of induction for 3 individuals followed an S shaped curve and the data was fitted to a modified kinetic model of gene transcription. From this model, wh ich assumes a cooperativity effect, transcriptional and RNA degradatio n rate constants could be calculated. The rate constant for transcript ion was doubled with the doubling of CdCl2 concentration, but the rate constant for RNA degradation was independent of Cd concentration.