Awardees

Nils Krietenstein  |  Rando Lab  |  Human Frontier Science Program Fellowship

Eukaryotic genomes are organized into a highly-compacted nucleoprotein complex known as chromatin. Hi-C and high-resolution microscopy studies reveal organization of chromosomes at multiple levels, from chromosome territories, to MB-scale functional domains that are spatially separated from each other, to shorter contact domains often called topological associated domains (TADs). While genetic studies in cell culture coupled with Hi-C or high-resolution microscopy reveal key roles for a variety of factors in higher-order chromatin folding, our understanding of chromatin fiber folding largely derives from biochemical studies in vitro. Mostly, these in vitro studies rely on artificial, homogenous chromatin templates that do not reflect the heterogeneous local folding properties of in vivo chromatin.

The aim of this project is to approach higher-order chromatin folding and chromosome organization biochemically. Micro-C detects internucleosomal interactions, which refer to local chromosome folding, by identifying nucleosomal DNA sequences and is therefore equally suitable for in vivo and in vitro studies. I will use chromatin prepared from cells (ex vivo) and in vivo-like in vitro reconstituted chromatin for chromatin compaction studies. With Micro-C I will be able to measure autonomous salt-dependent chromatin folding driven by all endogenous factors (ex vivo chromatin) or solely by histone-DNA interactions. Biochemical manipulation will allow to remove or test individual candidate factors.

This biochemical approach will help to decipher the regulatory role of higher-order chromatin organization on DNA templated processes, such as gene regulation.