Épigénétique et mémoire cellulaire – Edith Heard

Edith HeardCollège de FranceEpigénétique et mémoire cellulaireAnnée 2024-2025Conférence - Stephen Quake : Understanding the Mysteries of the Cell: How Do Mutations Arise in Our Bodies?Stephen QuakeHead of Science at the Chan Zuckerberg Initiative and Lee Otterson Professor at Stanford UniversityStephen Quake est invité par l'assemblée du Collège de France sur proposition de la Pr Edith Heard.RésuméThe question of how heritable mutations arise is one of long-standing interest in biology. In the case of bacteria, there was a debate about whether mutations arise as a consequence of adaptation to selective pressure from the environment, or whether they are pre-existing in populations even in the absence of such selective pressure. This was famously resolved as the latter by Luria and Delbruck. Genomic technologies now allow us to ask similar questions in humans. How is genetic diversity generated and what are the consequences? How do mutations acquired during the course of our life sometimes lead to cancer, and can we understand the evolutionary history of a tumor? My lecture will discuss these issues and illustrate how we have used single cell genomics to provide answers to some of these questions.Stephen QuakeStephen Quake is Head of Science at the Chan Zuckerberg Initiative, where he oversees CZI's science grant programs, technology development, and the CZ Biohub Network. He has received numerous awards for his contributions to science and is one of only two dozen scientists elected to all three National Academies. Steve also holds a faculty position at Stanford University, where he is the Lee Otterson Professor of Bioengineering and Applied Physics. Previously he was the founding co-president of the Chan Zuckerberg Biohub (2016-2022), investigator of the Howard Hughes Medical Institute (2006-2016), and professor at the California Institute of Technology (1996-2005).

Edith HeardCollège de FranceEpigénétique et mémoire cellulaireAnnée 2024-2025Conférence - Stephen Quake : Understanding the Mysteries of the Cell: How Do Many Cell Types Arise From One Genome?Stephen QuakeHead of Science at the Chan Zuckerberg Initiative and Lee Otterson Professor at Stanford UniversityStephen Quake est invité par l'assemblée du Collège de France sur proposition de la Pr Edith Heard.RésuméAlthough the genome is often called the blueprint of an organism, it is perhaps more accurate to describe it as a parts list composed of the various genes that may or may not be used in the different cell types of a multicellular organism. Although nearly every cell in the body has essentially the same genome, each cell type makes different use of that genome and expresses a subset of all possible genes. This has motivated efforts to characterize the molecular composition of various cell types within humans and multiple model organisms, both by transcriptional and proteomic approaches. We used single cell transcriptomics to create a human reference atlas comprising more than one million cells from 24 different tissues and organs, many from the same donor. This atlas enabled molecular characterization of more than 400 cell types, their distribution across tissues, and tissue-specific variation in gene expression, and provides an experimental basis to understand the cell type diversity which can be generated from a single genome.Stephen QuakeStephen Quake is Head of Science at the Chan Zuckerberg Initiative, where he oversees CZI's science grant programs, technology development, and the CZ Biohub Network. He has received numerous awards for his contributions to science and is one of only two dozen scientists elected to all three National Academies. Steve also holds a faculty position at Stanford University, where he is the Lee Otterson Professor of Bioengineering and Applied Physics. Previously he was the founding co-president of the Chan Zuckerberg Biohub (2016-2022), investigator of the Howard Hughes Medical Institute (2006-2016), and professor at the California Institute of Technology (1996-2005).

Edith HeardCollège de FranceEpigénétique et mémoire cellulaireAnnée 2024-2025Conférence - Virginijus Šikšnys : From CRISPR-Cas Immunity to Targeted Genome Editing and BeyondVirginijus ŠikšnysProfesseur, Vilnius University, VilniusVirginijus Šikšnys est invité par l'assemblée du Collège de France sur proposition de la Pr Edith Heard.RésuméBacteriophages (viruses that infect bacteria) pose a lethal threat to bacteria. In response, bacteria evolved multiple defense barriers that comprise a primitive immune system of bacteria. CRISPR-Cas system functions as an adaptive immune system that provides resistance against invading viruses. CRISPR-Cas immunity is enabled by programmable nucleases that act as DNA scissors that recognize and destroy invading nucleic acids. Easy programmability of CRISPR-Cas nucleases paved the way for the development of versatile tools for targeted genome engineering. Currently, Cas9 and Cas12 CRISPR-Cas nucleases are rapidly advancing into the clinics for the treatment of different diseases. Despite this exciting progress, significant challenges remain and need to be overcome, including precise delivery to target tissues, safety related to off-target effects and immune interactions and low efficiency of gene insertions. Therefore, in order to optimize therapeutic potential of genome editing technologies, novel tools that are more compact, more precise and safer are highly desirable. Recently, very compact RNA-directed transposon-related TnpB nucleases have been identified enabling the development of a new class of DNA-scissors. Further exploration and systematic discovery of novel antiviral defense systems is likely to decode novel enzymatic functions that could be repurposed for technological applications.

Edith HeardCollège de FranceEpigénétique et mémoire cellulaireAnnée 2023-2024Conférence - Harold E. Varmus : How Can Science and Its Benefits Be Shared Globally? How Medical Science Can Be Used in Developing CountriesHarold E. VarmusPrix Nobel de physiologie ou médecineRésuméIn the final lecture, I will talk about the ways in which parts of the scientific enterprise are trying to create a world in which the opportunities to be a scientist and to share the benefits of science are available everywhere. I will talk about several initiatives, supported by governments or philanthropies, that either promote science as a global activity or improve access to advances in health care made possible by science. The initiatives will include examples funded by the US government, French-American collaborations, the World Health Organization, and others, to reduce the toll taken by malaria, cancers, and other diseases.

Edith HeardCollège de FranceEpigénétique et mémoire cellulaireAnnée 2023-2024Conférence - Harold E. Varmus : How Do Scientists Inform Others about Their Work? Why Evolving Publication Practices Are ContentiousHarold E. VarmusPrix Nobel de physiologie ou médecineRésuméI will talk about how scientists inform others about their results, with emphasis on the rise of scientific journals and the often excessive importance conferred upon work that appears in a few especially prestigious venues. A central element of this lecture will concern the use of the internet to make scientific information more accessible through public digital libraries, "open access" publication practices, preprint servers, and posts in social media. Problems associated with publication practices and peer review – including non-reproducibility, misconduct, and misuse of artificial intelligence – will also be discussed.