Jeannie Lee (Harvard) 3 - X Chromosome Inactivation: Spreading the Silence

Jeannie Lee (Harvard) 3 - X Chromosome Inactivation: Spreading the Silence

Recording date: 08/05/2019
Viewed: 2 times

https://www.ibiology.org/development-and-stem-cells/x-chromosome-inactivation The X chromosome is many time larger than the Y chromosome. To compensate for this genetic inequality, female mammalian cells undergo X chromosome inactivation of one X chromosome. Dr. Jeannie Lee explains the how and why of X chromosome inactivation. Part 3 of 3: And in her last talk, Lee describes how X inactivation is nucleated and spreads across the X chromosome. The Xist lncRNA is known to be necessary and sufficient for X inactivation. Lee describes experiments that identified the factors that tether Xist to the X chromosome and showed how Xist spreads to cover the entire X chromosome. She then goes on to explain that Xist blocks transcription in three ways: 1) Xist recruits factors that repress transcription via epigenetic modification such as histone methylation 2) Xist repels factors that open chromatin preparing it for transcription and 3) Xist changes the 3 dimensional organization of chromosomes. Lee ends with a model of our current understanding of the complex but critical process of X chromosome inactivation. Speaker Biography: Dr. Jeannie Lee is a Professor in the Department of Genetics at Harvard Medical School and in the Department of Molecular Biology at Massachusetts General Hospital (MGH). Her lab uses X chromosome inactivation as a model to study epigenetic regulation by long noncoding RNAs. Lee received her AB in biochemistry and molecular biology from Harvard University and her MD/PhD from the University of Pennsylvania School of Medicine. She was a postdoctoral fellow at the Whitehead Institute and a resident at MGH before joining Harvard/MGH as a faculty member in 1997. Lee was also an HHMI Investigator from 2001-2018. She is a member of the National Academy of Sciences and a Fellow of the American Association for the Advancement of Science. Lee has been honored with numerous awards including the 2016 Centennial Prize from the Genetics Society of America, the 2016 Lurie Prize from the Foundation for the National Institutes of Health, and the 2010 Molecular Biology Award from the National Academy of Sciences. In 2018, she was President of the Genetics Society of America. Learn more about Dr. Lee’s research here: https://www.x-inactivation-lee-lab.org

Jeannie Lee (Harvard Medical School, Massachusetts General Hospital)


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