Yamanaka Team Finds Retroviruses' Key Roles in Creating iPS Cells

Tokyo, Aug. 4 (Jiji Press)--Certain retroviruses play important roles in creating induced pluripotent stem cells, a team of researchers led by Kyoto University Prof. Shinya Yamanaka, a Nobel laureate for inventing iPS cells, has found. The human endogenous retroviruses are hyper-activated during the cell reprogramming process, but if their activity does not weaken once the process is complete and cells acquire full pluripotency, defective iPS cells will result, the researchers said. This finding could lead to the development of an efficient method to make iPS cells, which can develop into almost any type of tissue, other experts said. In production of iPS cells, about 10 pct of output is usually defective, but the reason has been unknown, according to Yamanaka and his colleagues at the university's Center for iPS Cell Research and Application, including lecturer Kazutoshi Takahashi and researcher Mari Ohnuki. Details of the study were made available in the online version of the Proceedings of the National Academy of Sciences of the United States. "I was surprised to know that retroviruses play key roles in the iPS cell reprogramming mechanism," Yamanaka said. "I feel many things remain to be discovered in the field, and I expect basic studies to be promoted." END