Embryonic cytoplasmic extracts rescue murine androgenones to the blastocyst stage.

Androgenones (paternally derived genome) show a significant inability to form a blastocoele cavity. Eighty percent of these embryos die or arrest at earlier stages. Factor(s) from both normal and parthenogenetic late preimplantation embryos injected into each blastomere of androgenetic 4-cell stage can rescue more than twice as many to the blastocyst stage (47.2% versus 19.2% for non-injected androgenones). This factor(s) becomes available beginning at the 4-cell stage and is titratable. Injected total cytoplasmic mRNA will also cause a rescue response. Isolating this specific factor message(s) will permit the eventual cloning of possibly the earliest parentally imprinted gene(s) expressed during development.