ISOLATION OF CDNA LIBRARIES FROM INDIVIDUAL HUMAN PREIMPLANTATION EMBRYOS

Although available data from the mouse model suggest that morphogenesi s during preimplantation development is dependent on the expression of embryonic genes, convincing data for human preimplantation embryos ar e missing. To investigate the expression of genes involved in human pr eimplantation development we constructed cDNA libraries from human ind ividual blastocysts and screened them for the expression of beta-actin , Coss, homeoboxes OCT-3 and HOXA4, and HLA-G and hMLH-1 genes, beta-a ctin, Coss, and OCT-3 were detected by reverse transcription-polymeras e chain reaction (RT-PCR), while HOXA4, HLA-G and hMLH-1 were undetect ed. Sequencing of 48 random clones from two libraries revealed a diffe rent identity to the known genes including 99% identity to human histo ne 3.1 and human ribosome protein S25 complete cDNA. These data demons trate the feasibility of constructing cDNA libraries from individual h uman preimplantation embryos and their potential usefulness in the ass essment of the relevance of specific gene expression in the failures o f preimplantation development.