John D. Biggers

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We have recently reported the use of sequential simplex optimization methods to design a medium (SOM) that overcomes the block to development beyond two cells which occurs in vitro in embryos from an outbred strain of mouse. We have examined this medium and several others for their ability to foster development of CF1 female x B6D2F1 male mouse embryos(More)
Development of outbred CF1 mouse zygotes in vitro was studied in a chemically defined, protein-free medium both with and without amino acids. The addition of amino acids to protein-free potassium simplex optimized medium (KSOM) had little effect on the proportion of embryos that developed at least to the zona-enclosed blastocyst stage. In contrast, amino(More)
THE D-type cyclins (D1, D2 and D3) are critical governors of the cell-cycle clock apparatus during the G1 phase of the mammalian cell cycle. These three D-type cyclins are expressed in overlapping, apparently redundant fashion in the proliferating tissues. To investigate why mammalian cells need three distinct D-type cyclins, we have generated mice bearing(More)
The addition of amino acids to a modified simplex optimized medium (mKSOM) did not increase the percentage of blastocysts that develop from CF1 mouse ova fertilized in vitro. In contrast, the percentage of blastocysts that began to hatch and the number of cells in these blastocysts, particularly in the inner cell mass, was increased. The added amino acids(More)
A new medium derived from the use of sequential simplex optimization methods (SOM) that overcomes the block to development beyond two cells in vitro in embryos of the CF1-cultured strain of mouse has recently been described. Contrary to previous reports, glucose was shown to have no significant inhibiting effect on embryo development to the blastocyst stage(More)
Yin Yang 1 (YY1) is a zinc finger-containing transcription factor and a target of viral oncoproteins. To determine the biological role of YY1 in mammalian development, we generated mice deficient for YY1 by gene targeting. Homozygosity for the mutated YY1 allele results in embryonic lethality in the mouse. YY1 mutants undergo implantation and induce uterine(More)
Considerable advances in media development for the culture of preimplantation mammalian embryos have been made since mouse embryos were first cultured and successfully transferred to foster mothers. The purpose of this review is to detail the history of the development of chemically defined media for the culture of preimplantation embryos. Two approaches(More)
Culture media were developed for pronuclear-stage mouse embryos using simplex optimization, which has the benefit of being able to optimize several components simultaneously. Initially, several different media were generated. All media contained the same components, yet each medium was characterized by having a different component at a high concentration.(More)