STRAIN-SPECIFIC PROGRESSION OF ALPHA-AMANITIN-TREATED MOUSE EMBRYOS BEYOND THE 2-CELL STAGE

Mouse embryos produced by the fertilization of eggs from (B6D2)F1 and CF-1 mice differ in their ability tb complete the second cell cycle in the presence of alpha-amanitin. Essentially all embryos obtained from CF-1 mothers arrest at the two-cell stage when cultured from the late one-cell stage in or-amanitin at concentrations that prevent zygotic genome activation, while up to 15% of the embryos obtained from (B6D2)F1 mothers can progress to the three- to four-cell stage. This occurs even at a-amanitin concentrations that are fivefold greater than that required to prevent gene transcription. We propose that eggs of certain strains of mice may be endowed with greater supplies of macromolecules to support early development and that a percentage of these embryos can complete the second cell cycle in the absence of transcription. This difference may contribute to the strain-dependent differences in development in vitro. (C) 1995 Wiley-Liss, Inc.