logo_iii.gif (13972 Byte)

Mechanisms of embryo-maternal

Coordinator: Prof. Dr. Eckhard Wolf, Genzentrum der LMU-München

Unit 478

Project 6:

Transcriptomics of the bovine preimplantation embryo 
Heiner Niemann, James Adjaye

In cattle breeding, early embryonic mortality in the range of 35-50% is associated with enormous economic losses. Moreover, the bovine embryo is an attractive complement to the mouse embryo for studying mechanisms of preimplantation mammalian development.
The major goal of this project is the analysis of the transcriptome in in vivo derived bovine preimplantation embryos using a bovine cDNA-array. Early stages up to 16-cell embryos are recovered from the oviducts of donor animals by using laparoscopic techniques. Later stages are flushed from the uterus. Embryos are pooled by stage, RNA is extracted and amplified. The mRNA expression profiles are analyzed using bovine Affymetrix arrays (22 k). Expression data are subjected to bioinformatic evaluation such as cluster and pathway analyses to identify expression patterns and regulatory mechanisms. Data will be stored in an open-access database. In parallel a custom bovine embryo array is developed, which is – in the first stage – based on previous results obtained by RT-PCR studies. Differentially expressed genes identified by the Affymetrix studies will be integrated in the embryo array. The final version of this embryo array will then be used to compare the transcriptome profiles of different stages of in vivo derived bovine embryos with those of in vitro produced or cloned embryos to identify transcriptome alterations and deviations from the in vivo “gold” standard. These first holistic and dynamic transcriptome studies of different sources of bovine preimplantation embryos represent an essential contribution to the systematic analysis of embryo-maternal communication.

Return to the projects main page.