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The Bioresource Engineering Division of the BioResource Center (BRC) and the Laboratory for Immune Regulation at RCAI have succeeded in cloning mice from natural killer T cells (NKT cells), a type of lymphoid cell, by direct nuclear transfer.
Although there have been examples of cloned animals in the past, such as Dolly the sheep, it was argued that such animals came from a rare stem cell, not from a differentiated cell in the body. The research teams demonstrate that direct nuclear transfer of a differentiated cell results in efficient establishment of embryonic stem (ES) cells and in generation of cloned mice. The efficiency of ES cell establishment using NKT cells was much higher than that used in conventional T cells. Techniques in molecular biology revealed that these cloned mice indeed originated from NKT cells. Importantly, the cloned mice were normal and fertile, and have lived for 60-80 % of the expected life span. These data demonstrate that a genome from fully differentiated cells is totipotent when transferred into an unfertilized egg. This research result was published in the U.S. science journal Current Biologyon June 21.