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SUMMARY:Chromatin structure of the inactive X chromosome revealed by in si
 tu cryo-electron tomography
DTSTART:20260922T161500
DTEND:20260922T180000
DTSTAMP:20260929T163415Z
UID:e1d51697eb319933bc3edce0b2656f1267d5767a5faefd05a4129fb0
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. Jeongyoon Choi (University of Oxford)\nThe intricate org
 anisation of chromatin in eukaryotic cells plays a central role in regulat
 ing gene transcription and other DNA templated processes. Prior studies us
 ing light microscopy\, biochemistry and genomics have implicated histone a
 nd DNA modifications\, histone variants\, chromosomal proteins\, non-codin
 g RNA and intrinsic biophysical properties of chromatin in determining chr
 omatin organisation across multiple scales. In this study we apply an inno
 vative approach\, direct visualisation of native chromatin structure and i
 ts modulation by different factors using cryo-electron tomography\, exploi
 ting the inactive X chromosome (Xi) in differentiating mouse embryonic ste
 m cells as a model system of facultative heterochromatin. We show that Xi 
 chromatin undergoes progressive compaction across scales\, from individual
  nucleosomes to chromatin domains. We observe an enrichment for histone H1
 -bound chromatosomes that are distributed to form the core of Xi chromatin
  domains. Moreover\, we demonstrate that histone deacetylation demarcates 
 chromatin domains. Specifically\, perturbations leading to Xi histone acet
 ylation dissolve discrete chromatin-domain boundaries\, resulting in a hom
 ogeneous chromatin distribution with a dense and uniform packing of nucleo
 somes. Together\, these findings illuminate the multiscale organisation of
  native facultative heterochromatin and the contributions of histone H1 an
 d histone acetylation to this organisation. This study opens a new avenue 
 for investigating how chromatin modification and structure relate to gene 
 activity in near-native cells.\n\n 
LOCATION:CH G1 495 https://plan.epfl.ch/?room==CH%20G1%20495
STATUS:CONFIRMED
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