Exploring the chromatin landscape in early development

WHEELER_U21DTP

The Neural Crest and Placodes are groups of cells found only in vertebrates, specifically in the embryo. They originate at the neural border between the ectoderm and neuroectoderm.

Once specified the Neural Crest undergo an epithelial to mesenchymal transition (EMT) and then migrate to various parts of the embryo where they differentiate into important tissues such as parts of the heart, the peripheral nervous system, the cartilage of the face and pigment cells. Placodal cells differentiate into major parts of sensorial organs such as the eyes, ears and nose. The Neural Crest and Placodes are therefore of importance for normal development and errors in their development are the cause of many birth defects.

Understanding the regulatory elements, such as enhancers, required for specification of the Neural Crest and Placodes is important in order to understand how they are first specified and then induced during development. Understanding these processes will help in developing techniques to engineer specific cells and tissues that the neural crest and placodes give rise to and which could be used in stem cell and regenerative therapies. ATAC-seq is a method to identify ‘open’ regions in the chromatin landscape which can correspond to active enhancers and promoters. We have previously carried out ATAC-seq on Xenopus embryonic tissue induced to form neural crest and neural ectoderm to determine active enhancers and promoters. In this project the student will:
(1) Generate ATAC-seq data on Xenopus embryonic ectoderm organoids induced to form placodal tissue.
(2) Use bioinformatics to analyse the data and compare it to the neural crest data. Differential analysis will uncover specific neural crest and placodal enhancers.
(3) Test and validate potential enhancers using transgenic and CRISPR/Cas9 technologies.

References:
Gi Fay Mok, Leighton Folkes, Shannon Weldon, Eirini Maniou, Victor Martinez-Heredia, Alice Godden, Ruth Williams, Grant N. Wheeler, Simon Moxon, Andrea E. M√ľnsterberg (2020). Characterising open chromatin identifies novel cis-regulatory elements important for paraxial mesoderm formation and axis extension. bioRxiv, doi: https://doi.org/10.1101/2020.01.20.912337

Victoria L. Hatch, Marta Marin-Barba, Simon Moxon, Christopher T. Ford, Nicole J. Ward, Matthew L. Tomlinson, Ines Desanlis, Adam E. Hendry, Saartje Hontelez, Ila van Kruijsbergen, Gert Jan C. Veenstra, Andrea E. M√ľnsterberg and Grant N. Wheeler (2016). The Positive Transcriptional Elongation Factor (P-TEFb) is required for Neural Crest Specification. Developmental Biology, 416: 361-372

Hoppler S and Wheeler GN. (2015) It’s about time for neural crest. Science, 348 (6241):1316-1317