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Insulin-Like Growth Factor Ii Acts Through An Endogenous Growth Pathway Regulated By Imprinting In Early Mouse Embryos, Daniel A. Rappolee, Karin S. Sturm, Ole Behrendtsen, Gilbert A. Schultz, Roger A. Pedersen, Zena Werb

Department of Obstetrics and Gynecology Research Publications

We present evidence that insulin-like growth factor II (IGF-II) mediates growth in early mouse embryos and forms a pathway in which imprinted genes influence development during preimplantation stages, mRNA and protein for IGF-II were expressed in preimplantation mouse embryos, but the related factors IGF-I and insulin were not. IGF-I and insulin receptors and the IGF-II/mannose-6-phosphate receptor were expressed. Exogenous IGF-II or IGF-I increased the cell number in cultured blastocysts, but a mutant form of IGF-II that strongly binds only the IGF-II receptor did not. Reduction of IGF-II expression by antisense IGF-II oligonucleotides decreased the rate of progression to the blastocyst …