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Title: POSITIVE SELECTION OF TRANSGENIC BOVINE EMBRYOS IN CULTURE

Author
item BONDIOLO, KENNETH - GALAGEN,INC
item WALL, ROBERT

Submitted to: The International Embryo Technology Society
Publication Type: Proceedings
Publication Acceptance Date: 8/30/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: A major constraint for the production of transgenic cattle is the cost of transferring embryos to recipients which do not produce transgenic cattle. Attempts to select transgenic embryos biopsy & assay for the transgene have not been very efficient. We chose a non invasive approach for selecting transgenic embryos during culture. To accomplish this we constructed a transgene which included the neomycin resistance gene (neo) driven by a promoter know to be active in preimplantation embryos. A total of 683 zygotes were microinjected & placed into culture (without G418) of which 354 (52%) cleaved. AT 48 h post injection 138 & 160 embryos were assigned to the control (medium alone) or G418 treatments (100 ug/ml of medium), re- spectively. The control treatment resulted in 26 (19%) while those cultured with G418 resulted in 15 (9%) blastocysts. Control blastocysts had a mean of 88.3 cells of which 24.5 (28%) stained for B-Gal activity. Blastocysts cultured in G418 had a mean of 55.3 cells of which 45.7 (83%) stained for B-Gal. Twenty one of 26 (81%) control blastocysts had some cells with B-Gal activity while all the G418 blastocysts had some cells with B-Gal activity. Nine of 15 (60%) blastocysts in the G418 treatment had greater than 80% cells with B-Gal activity while only 4 of 26 (15%) controls had greater than 80% cells with B-Gal. Further studies are anticipated to determine the viability of these emryos and if they will result in a higher proportion of transgenic fetuses.