Microarray technology to assess gene expression profiles of human oocytes and embryos.
   
Steuerwald, N 1,2,4 ; Bermúdez, MG* 1 ; Wells, D 4 ; Munné, S 1 ; Cohen, J 3,4 . 1 Reprogenetics, 101 Old Short Hills Road, West Orange, NJ 07052, USA; 2 Department of Biology, University of North Carolina, Charlotte, NC 28223, USA; 3 Tyho-Galileo Research Laboratories, PO Box 237045 Ansonia Station, NY 10023, USA; 4 ART Institute of NY & NJ, 101 Old Short Hills Road, West Orange, NJ 07052, USA.

Introduction: The current knowledge of molecular mechanisms during early development is pretty rudimentary. Further characterization of these mechanisms governing development in early stages in oocytes and embryos is needed to understand gene activity and the response to external factors in the ovary and reproductive tract.

Materials & Methods: Nonviable human oocytes and embryos were obtained from patients undergoing IVF. As such, this material is potentially compromised. Isolated RNA was linearly amplified, labeled and fragmented, finally being applied to Affymetrix GeneChip expression probe microarrays.

Results: Subtle differences in expression were evident between oocytes of the same developmental stage, but derived from different patient subpopulations, probably due to genetic differences, which contribute to the patient's phenotype. Comparison of embryos at different stages of development revealed large divergences of gene expression. In this case, differentially expressed genes are predicted to be responsible for orchestrating the progression through the different stages of preimplantation development.

Conclusions: The orderly succession of events during oocyte maturation and embryonic development belies the complex interactions coordinated by the genes being expressed and/or silenced. Variations in expression observed between oocytes of diverse developmental competence is indicative of the functional differences. These differences in expression may form the basis of future methodologies to predict enhanced developmental prognosis and additional insights into the regulation of oocyte maturation and preimplantation development, thus providing potential targets for diagnosis and infertility treatment.

Keywords: gene expression, human oocytes, microarray, RNA.