Molecular markers in embryonic stem cells

Embryonic stem cells are pluripotent cells derived from mouse blastocysts, which have the capacity to differentiate in vitro into a wide variety of ce ll types. Based on this potential the embryonic stem cell test (EST) has be en developed, which represents an assay system for the classification of co mpounds for their teratogenic potential, based on the morphological evaluat ion of contracting myocard cells compared to the cytotoxic effects on undif ferentiated stem cells and adult 3T3 fibroblasts. To expand the EST, the qu antitative expression of the alpha- and beta -myosin heavy chain (MHC) gene s under the influence of test compounds was studied employing real-time Taq Man PCR analysis. The molecular evaluation of the MHC genes allows a higher sensitivity for the classification of substances and the transfer of the E ST to the molecular level allows to start experimental procedures at day 9 of culture. Thus, the modulated EST holds promise as a new easily quantifia ble in vitro screening assay in teratology. (C) 2001 Elsevier Science Ltd. All rights reserved.