Nathalie Dostatni

Epigenetic Plasticity and Polarity of the Embryo

Nathalie Dostatni Morphogenetic gradients, transcription, chromatin assembly, Drosophila, development

Development & Epigenesis Exploring the Bicoid morphogen gradient in collaboration with physicists aims at providing a dynamic quantitative understanding of axis formation in Drosophila

Epigenetics Exploring the function of CAF-1 in Drosophila allows using genetics to dissect the role of the complex in endocycling cells, meiotic cells and cells undergoing asymmetric division, three important contexts for a developing embryo for which there are no tissue culture models

Our work aims to elucidate how cells acquire and maintain their identity during development. As the “epigenome” predominantly determines cellular identity in eukaryotes, we focus on the role of chromatin dynamics to maintain genome integrity and gene expression during development. Our model system, the Drosophila fruit fly, is ideally suited for classical and molecular genetic approaches, as it develops rapidly and is particularly well adapted for leading-edge imaging. Our recent work focuses on the CAF-1 chromatin assembly factor and on the Bicoid transcription factor gradient.

Figure 1. A) The young fruit fly embryo is a unique cell containing a large number of nuclei (blue). Expression of the hunchback gene is detected by RNA FISH (green). B) Schematized view of the embryo, after automatic treatment in 3D. Nuclei are labelled in green, blue or white according to a color code (cartoon below panel A). At cycle 11, a large majority of nuclei in the anterior already exhibit a bi-allelic expression of the gene. Anterior is left.

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Figure 2: DNA FISH for pericentric heterochromatin repeats (pink) in the egg chamber. Females expressing only one dose of the CAF-1 large subunit produce oocytes with a high proportion of misalignment of these regions. These defects correlate with increased aneuploidy, which result from the aberrant segregation of chromosomes that did not recombine in meiosis I. DNA (blue).

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