Embryonic transcription is a crucial process for the creation of new life. To clarify the mechanism of embryonic transcription, we investigated the expression and function of the erythroblast transformation specific (ETS) domain containing transcription factors (TFs) during preimplantation development in mice. The expression levels of several ETS TFs, i.e., elsrp71, elf3, and spic, increased after fertilization and remained at a high level until the blastocyst stage. To clarify the function of these TFs, we performed gene suppression using RNA interference, which revealed that they were involved in regulating development to the blastocyst stage. Furthermore, we found that suppression of ETS TFs affected the transcription of e1F-lA and oct3/4 genes whose expression is regulated by TATA-less promoters in the embryos. These results suggest that ETS TFs function in the regulation of transcription with TATA-less promoters in preimplantation embryos, which is essential in preimplantation development. (c) 2006 Elsevier Inc. All rights reserved.