SEQUENCE-ANALYSIS OF LIBRARIES FROM INDIVIDUAL HUMAN BLASTOCYSTS

Purpose: It has recently become possible to construct cDNA libraries f rom individual human blastocysts to investigate the expression of embr yonic genes in human preimplantation development. We have previously r eported the expression of beta-actin, CD-59, and homeobox OCT-3 and id entified almost-complete homology of sequences to human histone 3.1 an d human ribosome protein S25. In the present paper; our further sequen cing analysis of cDNA libraries from single human blastocysts is descr ibed. Methods: cDNA libraries were constructed from 13 blastocysts. Se quence analysis was performed in 120 clones from one of these cDNA lib raries with fragments of 50 to 1000 bp. Their sequence identity was an alyzed using the expressed sequence rag (EST) database. Results: The p resence of two housekeeping genes, hexokinase I and serine/threonine p hosphorylase, and four other ESTs was demonstrated, the identity of wh ich, with particular gene expression in preimplantation development, h as not yet been established. Conclusions: The data demonstrate the use fulness of constructing cDNA libraries from individual human blastocys ts and their value in the analysis of genetic expression in human prei mplantation development.