Jaenisch, Rudolf

RUDOLF JAENISCH IS a member of the White—head Institute and Professor of Biology at Massachusetts Institute of Technology (Cambridge, MA). Jaenisch's long and impressive career has focused mainly on epigenetic mechanisms in cells. The study of epigenetics relates to understanding how environmental factors surrounding the cell alters gene expression without changing the DNA sequence and what impact this has on the function and development of a cell. To do this Jaenisch has used a range of tools including stem cells, genetically altered mice and cloning techniques.

Jaenisch was born in 1942 in Germany. Jaenisch enrolled in a medical program and pursued additional research opportunities in a leading German laboratory of P. H. Hofschneider where he produced some seminal work studying bacterio—phages. He did the rest of his clinical training in Germany and then a post doctoral fellowship in the United States with Arnold Levine at Princeton. Focusing on the virus SV40 and the mechanisms of cancer, Jaenisch moved towards using mice as models for cancer and became fascinated with how and why certain types of cells may be susceptible to getting cancer. Working with the notable developmental biologist Beatrice Mintz, he soon added early embryo development to his list of interests. After starting his own lab at the Salk Institute in California, Jaenisch began collaborating with Paul Berg and others to develop novel ways to detect viral DNA within infected mice. This led to the idea of transgenic animals and finally cloning. A brief time spent back in Germany was followed by his final move to the Whitehead Institute where his work moved to epigenetics and the study of how DNA methylation could control gene expression.

Jaenisch was impressed by the creation of the first cloned animal—Dolly the sheep by Ian Wilmut using somatic cell nuclear transfer. He set out to try to understand how a fully differentiated nucleus from and adult cell could be “repro—grammed” by the egg's cytoplasm. He thought this was the most pure form of epigenetics, and by studying signals involved with this reprogram—ming it may be possible to better understand biology in general. However, he was also well aware that many clones he produced were not perfect and had developmental or adult problems. One of his goals is to understand why these problems exist and how to fix them. His most recent work has included some seminal papers on induced plu—ripotent stem (iPS) cells. In an amazing paper he [Page 280]took skin fibroblasts from an adult mouse with sickle cell anemia, an inherited disease, generated iPS cells from them, repaired the defective gene in these cells, differentiated the newly corrected cells into a blood lineage, and cured the same mouse of the disease through bone marrow transplantation. This stands as a testament to his amazing scientific and technical skills and his ability to keep on top of the most exciting discoveries with high quality papers.

Jaenisch's awards include the Peter Gruber prize in Genetics (2001), the Robert Koch Prize for Excellence in Scientific Achievement (2002), and the Charles Rodolphe Bruphacher Foundation Cancer Award (2003). In 2003, Jaenisch was elected to the National Academy of Sciences.

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