Abstract
Thymocytes from fetal, newborn, and adult mice were transferred into enucleated oocytes by standard micromanipulation. The developmental ability of oocytes receiving a thymocyte was examined in vitro. Most of the reconstituted eggs were successfully activated and formed a pronucleus-like structure. The percentage of reconstituted eggs developing to the 2-cell stage was high, 75-84%, but development of embryos to more advanced stages was limited. Only 8 and 1% of the reconstituted eggs receiving a thymocyte from fetal and newborn mice developed to the blastocyst stage, respectively. None developed to the 8-cell stage when a thymocyte from adult mice was transferred. Analysis of newly synthesized proteins of the reconstituted embryos showed that 68-70 kDa heat shock proteins, initial markers of embryonic genome activation, were synthesized at the late 2-cell stage.
