Molecular, Structural, and Functional Studies of Leukemia-Associated Transcription Factor-Nucleoporin Fusion Proteins

Nup98 is a mobile nucleoporin that localizes both at the nuclear pore complex and within the nucleus. Nup98 is frequently rearranged to form leukemogenic Nup98-fusion proteins with various partners.

Nup98-HoxA9 (NHA9), a fusion between phenylalanine-glycine-rich (FG-rich) region of Nup98 and the homeobox transcription factor (TF) HoxA9, is one of the most frequent Nup98-fusion associated with acute myeloid leukemia.

The physiological role of NHA9 in hematopoietic development has been gradually established in the past decade at the cellular level.

However, the plasticity and the phase separation behavior of such intrinsically disordered proteins (IDPs) largely hinder our understanding of their functions in gene regulation at the molecular level.

In this project, I will develop platform technologies that combine chemical biology, microfluidics, and high-resolved molecular imaging to study the structure and biophysical function of NHA9 in vitro and in cells, and open up a new pathway to unravel its role in gene dysregulation from molecular perspective.

Firstly, I will dual-label NHA9 at specific sites using the cutting-edge genetic code expansion technology developed by the host laboratory, and characterize the plasticity of NHA9 in live cells using Fluorescence lifetime imaging (FLIM) based Förster resonance energy transfer (FRET) platform.

Next, I will use my strengths in microfluidics to design a new platform for tracking the phase separation behaviors of NHA9 with high temporal resolution in vitro.

Finally, I will fuse NHA9 with proximity-dependent biotin identification (BioID) tags, and visualize the dynamic interaction networks of NHA9 using super-resolution microscopy (SRM) in live cells.

By integrating those interdisciplinary approaches, the proposed research would make a conceptual breakthrough in understanding the molecular mechanism of NHA9-driven leukemogenesis and may provide a rationale for the search of potential therapeutic approaches in the future.