PARENT SESSION
Gene Regulation & Function

ANALYSIS OF GENES EXPRESSED DURING PREIMPLANTATION BOVINE EMBRYO DEVELOPMENT.

Ofulue, Esther¹, First, Neal², ^{1 2}

ABSTRACT- We have used the differential display PCR, Reverse Northern dot-blot, and RT-PCR to locate and clone transcribed sequences of thirty-two genes that are differentially expressed at in vitro fertilized preimplantation embryo stages of 2-cell, 8-cell, 16-cell, compacted morula, and blastocysts. Genbank sequence analyses revealed that pEN14B, pEN14C, pEN22, and pEN23 share 90%, 97%, 76% and 94% homology, respectively to the 3' ends of human thermostable phenol sulfotransferase gene, human cytoplasmic chaperonin hTRiC5 mRNA, putative prenylated protein gene, and human mRNA for alanyl-tRNA synthetase. These genes are differentially expressed from the embryonic genome at the morula and blastocyst stages. pEN21 and pEN35 which are expressed at all embryo stages but at low levels at the 2-cell stage, share 100% homology with bovine mitochondrial genome regions encoding NADH dehydrogenase subunits 4 & 5 and ATPase subunit 6, respectively. Several other genes with interesting patterns of stage-specific expression (see Table 2) which may relate to stage-specific functions share homologies with known genes as shown in Table 1. The pattern of expression of these genes in nuclear transfer cloned bovine embryos is being examined in order to provide some explanations for the abnormal or failed development of cloned animals.

KEY WORDS: differential display PCR, nuclear transfer cloned embryo, gene expression, early embryo development