CRYOMACRO

Regulation of gene expression is fundamental for cell fate, through the crucial interplay between DNA sequence, nucleosomes and transcription factors. However, mechanisms governing these interactions orchestrating cell identity and gene expression profiles remain elusive. In eukaryotes, except from histones (H2A, H2B, H3 & H4) building up a canonical nucleosome octamer, other variants alter the nucleosomal structure and function.

This research proposal focuses on histone variant macroH2A1.1 (mH2A1.1), implicated in safeguarding mesenchymal identity. To investigate native mH2A nucleosomes, cryo-electron microscopy (cryo-EM) and crosslinking mass spectrometry (XL-MS) will be employed in an integrative approach. Specifically, intact nucleosomes will be isolated from mouse embryonic fibroblasts (MEFs), stabilizing the nuclear assembly for high-resolution cryo-EM studies. Additionally, large-scale sequencing data and XL-MS will be combined to map both the structure-sequence traits as well as pioneer transcription factors governing mH2A function.

Obtaining a high-resolution cryo-EM structure of a mH2A nucleosome will mark a milestone in the structural characterization of chromatin entities, shedding light on the crosstalk among decision-making complexes within the nucleus, forming dynamic networks of cell-type specific gene regulation. This research will exploit the newly established cryo-EM lab (NHRF, Athens, Greece), the first in Southeast Europe. Under the advisory support of Prof. Kastritis and Dr. Thanos, the researcher will leverage expertise in high-resolution cryo-EM and biochemistry, fostering scientific advancements in an international space.

This HFRI postdoctoral project promises to advance the understanding of subcellular mechanisms, bridging biochemistry and transcriptomics with computational structural biology. Through this project, the principal investigator will also enhance teaching and leadership skills, contribute to the scientific community, and establish a promising scientific career.