Heat shock memory in preimplantation mouse embryos.

To investigate the consequences of possible physiologic stress to embryos caused by in vitro fertilization procedures, we used heat shock response in preimplantation mouse embryos as a model. A heat shock "memory" was discovered that renders cleavage-stage embryos more responsive at the transcriptional level to secondary perturbation with very low doses of heat, even several cell cycles after the initial stress has occurred. Copyright 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.