Beta-N-acetylhexosaminidase activity in mouse oocytes and preimplantation embryos.

Beta-N-Acetylhexosaminidase is a lysosomal enzyme; mutation in this protein leads to Tay-Sachs or Sandhoff disease. We have developed an assay for the beta-N-acetylhexosaminidase in mouse oocytes and preimplantation embryos. Activity was low in oocytes and zygotes and started to rise from the late 2-cell stage. By using alpha-amanitin, an inhibitor of DNA-dependent RNA polymerase, we were able to show that the first embryonic mRNA transcriptions of the beta-N-acetylhexosaminidase genes take place between 38 and 46 h post HCG (early 2-cell stage) and between 46 and 54 h post HCG (late 2-cell stage).