Sixième réunion du GdR Architecture et Dynamique Nucléaire (ADN)

Liste des abstracts

18. CTCF mediates allele-specific sub-TAD organization at paternally imprinted gene loci

Dr Daan Noordermeer (Institut de Biologie Integrative de la Cellule)

Mammalian genes can be mono-allelicly expressed depending on their parental origin, a process called imprinting. Though only a relatively small number of genes are imprinted, this mechanism is of great importance for correct embryonic development. Imprinting is governed by allele-specific DNA methylation at defined Imprinting Control Regions (ICRs), which often influences the binding of...

19. How pinching a DNA plectoneme facilitates the interaction between distant genes

Prof. Nicolas Destainville (Univ. Toulouse III-Paul Sabatier)

Normally separated by a distance on the order of 10 nm, the two opposite double-strands of a DNA plectoneme must be brought closer if a protein implicated in genetic regulation is to be bound simultaneously to both strands. We propose an analytic calculation of the energetic barrier, of elastic nature, required to bring closer two loci situated on the two double-strands. We also examine how...

23. Imaging DNA repair at the single molecule level

Mlle judith Miné-Hattab (Institut Curie)

Our genome is constantly damaged by a variety of exogenous and endogenous agents. Among the various forms of DNA damage, double-strand breaks (DSBs) are the most cytotoxic and genotoxic for the cell. Failure to repair such lesions leads to genomic instability or cell death. In higher eukaryotes, mutations in DNA repair genes lead to cancer predisposition. Eukaryotic organisms use several...

26. Making efficient coarse-grain models for long polymers: application to chromatin folding

Dr Surya Ghosh (Post Doc)

The physical organization of a chromosome is very crucial for cell functions. Chromosomes are, in general, long and dense-packed polymers. Emphasizing on these characteristics, we developed a generic strategy to develop efficient coarse-grain homopolymer models for chromosomes. From a proper time mapping using the monomer mean-squared displacement, we show that our simulation scheme not only...

25. Out of equilibrium dynamics of a cross-linking polymer: chromatin as a case study

Vittore Scolari (Institut Pasteur)

The structural investigation of large macro-molecular assemblies is an essential step towards understanding the molecular mechanisms at work in cells. Due to the very unstable and labile nature of these assemblies most assays rely on a fixation step, typically achieved using formaldehyde cross-linking, to freeze and capture contacts made by proteins and nucleic acids. Propelled by rapid...

16. Polymer model for reconstructing chromatin and generating SPTs

M. Ofir Shukron (ENS)

Chromatin organization is probed by chromosomal capture data,from which the encounter probability (EP) between genomic sites is represented in a large matrix. However, this matrix is obtained by averaging the EP over cell population, where diagonal blocks called TADs, contains hidden information about sub-chromatin organization. Our aim here is to elucidate the relationship between TADs...

22. Surfing on protein waves: proteophoresis as a mechanism for bacterial genome partitioning

Dr Jean-Charles WALTER (Université de Montpellier)

Efficient bacterial chromosome segregation typically requires the coordinated action of a three-component, ATP-fueled machinery called the partition complex. We present a phenomenological model accounting for the dynamic activity of this system. The model is obtained by coupling simple linear reaction-diffusion equations with a *proteophoresis*, or ``volumetric'' chemophoresis, force field...

21. TALEs fused to chromatin modifiers for epigenetic engineering at satellite DNA repeats in mouse and human centromeric regions

Mlle Judith Lopes (INSERM)

Centromeric regions of eukaryotic chromosomes contain large numbers of tandemly repeated DNA sequences, also called satellite DNA sequences. These sequences represent the main component of constitutive heterochromatin, a compact type of chromatin. They also support the attachment of the kinetochore, thereby contributing to the stability of the genome. Although centromeric repeats are left out...

24. The cohesin complex is required to maintain chromosome integrity at DSB sites

Dr karine dubrana (IRCM-CEA)

A single DSB can be lethal if unrepaired, particularly in a haploid organism like yeast, and may lead to loss of genetic information and chromosome rearrangements if repaired improperly. In this context, maintaining DSB extremities in close proximity until repair is likely a crucial step to avoid illegitimate joining or initiation of independent recombination events from unrelated chromosome...