Objective:
To improve the efficiecy of nuclear transfer in cattle by identifying the mechanisms responsible for developmental abnormalities that occur during early gestation so that cell lines from elite cows and bulls can be used for cloning.

Approach:
Bovine embryos and fetuses will be produced by artificial insemination, in vitro oocyte maturation/in vitro fertilization, and by in vitro oocyte maturation/somatic cell nuclear transfer. As specific times during gestation fetuses and placental tissues will be recovered and preserved for subsequent extraction and analysis of protein and mRNA. DNA microarray will be used to compare mRNA expression profiles and 2-D Gel electrophoresis, high performance liquid chromatography, and mass spectrometry will be used to compare protein expression patterns among the fetuses and among the placental tissues produced from the three sources. This information should provide a foundation to establish the major causes of embryonic and fetal mortality in cloned cattle.