Objective
Application of developments in the "new genetics", ranging from genome sequencing to the use of "ovum pick-up" from cows of high genetic merit, is dependent on a supply of viable in-vitro produced (IVP) embryos. Embryo-based technology in cattle has enormous potential and is being commercialized in every EU country but many of the small or medium size embryo-based biotechnology companies are finding it difficult to survive because of viability problems with IVP embryos. While the in-vitro fertilization rate is high (80%), only about 30 embryos are produced from every 100 fertilized oocytes, and following transfer to recipients the pregnancy rate is 35-40% compared to 60-65% for in vivo produced embryos. Following cryopreservation the viability of IVP embryos is even further reduced, resulting in pregnancy rates as low as 20-40% and this is a significant limitation in a commercial context. A major factor reducing IVP embrya viability is their failure, in a high proportion of cases, to undergo compaction and normal cell junction formation in the manner of in vivo embryos. Compaction, when cell-to-cell contact is made for the first time followed by the formation of tight intercellular junctions to form a barrier against the extra-embryonic environment, represents the first critical morphological stage when the embryo begins to function as a unified organism. A high proportion of IVP embryos fail to undergo compaction but 'jump' from noncompacted 16-32-cell stages to the blastocyst stage at day 8 resulting in delayed development and low viability. Despite the physiological and economic importance of compaction there is a lack of information on this critical event in cattle embryo development.
The objective is to determine the nature of the genetic, molecular, metabolic and/or cellular deficiencies in compaction and cell junction formation of IVP embryos with a view to increasing the proportion of IVP embryos undergoing compaction, thus increasing the proportion of viable embryos. This involves investigation of gene and protein expression of key compaction and cell junction genes, and simultaneous changes in metabolic parameters and the correlation of these measurements with the morphological events of compaction and cell junction formation. Regulation of these processes by signal transduction molecules will also be examined. Embryo transfer by the commercial partner will be the ultimate test of IVP embryo viability. This is an integrated study of the failure of compaction and cell junction formation in IVP cattle embryos at the levels of gene expression, protein synthesis, morphology and metabolism using the modern tools of RT-PCR, differential display PCR (DD-RT-PCR), in situ hybridization, confocal microscopy, nuclear transfer technology and non invasive metabolic assays.
The disciplines of molecular biology, biochemistry, immunocytochemistry and cellular physiology, from 6 major research institutes and an embryo-based biotechnology company (SME) in 5 countries of the EU will be applied to the study of IVP embryo production. The objectives specifically address the priorities of the Biotechnology Workprogramme AREA 3 (3.2.1) on Animal Physiopathology in that, through studies on basic reproductive mechanisms, they aim to improve the reproduction and selection of farm animals.
Keywords (max 10): cattle, embryo, compaction, gene, protein, metabolism, viability.
Fields of science (EuroSciVoc)
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques.
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques.
- medical and health sciencesclinical medicinegynaecologyreproductive medicine
- medical and health sciencesclinical medicineobstetrics
- medical and health sciencesbasic medicinephysiology
- agricultural sciencesanimal and dairy sciencedomestic animalsanimal husbandry
- medical and health sciencesclinical medicineembryology
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Call for proposal
Data not availableFunding Scheme
CSC - Cost-sharing contractsCoordinator
Athenry
Ireland