Ji-Joon Song

Timeline

1. 1999–2005

   A PhD at Cold Spring Harbor

   He earns a B.S. at Seoul National University in 1999, an M.S. at the Gwangju Institute of Science and Technology in 2001, and a Ph.D. at Cold Spring Harbor Laboratory in 2005.

2. 2004

   The Argonaute crystal structure

   In 2004, he and coauthors Stephanie K. Smith, Gregory J. Hannon and Leemor Joshua-Tor report in Science the crystal structure of the Argonaute protein from Pyrococcus furiosus at 2.25 angstrom resolution. It is the first structure of Argonaute, the catalytic enzyme of RNA interference, and its PIWI domain resembles ribonuclease H, which points to Argonaute as Slicer, the enzyme that cleaves messenger RNA.

3. 2005–2008

   Postdoctoral fellow at Harvard Medical School

   From 2005 to 2008, he is a postdoctoral research fellow and Jane Coffin Childs Fellow in the Department of Molecular Biology and Genetics at Massachusetts General Hospital, Harvard Medical School. In 2008, he and Robert E. Kingston publish a crystal structure of WDR5 bound to an MLL peptide, which shows that WDR5 uses the same pocket that binds histone H3.

4. 2009

   Professor at KAIST

   He joins KAIST's Department of Biological Sciences as a professor in 2009 and heads the Song Laboratory, which works on the structural biology of epigenetics. Lab members study the structural basis of nucleosome assembly and disassembly, binding partners of the huntingtin protein, and plant immunity.

5. 2019

   Abo1, a histone chaperone using ATP

   In 2019, his group publishes in Nature Communications cryo-EM structures of Abo1, the fission yeast homolog of the ATAD2 histone chaperone, and shows that it deposits histone H3–H4 onto DNA in an ATP-hydrolysis-dependent manner. Abo1 is the only known histone chaperone that uses ATP.

6. 2022

   An antisense strategy for huntingtin

   In 2022, his team and collaborators at ProQR Therapeutics, Université Grenoble Alpes and KTH Royal Institute of Technology report in the Journal of Clinical Investigation Insight that an antisense oligonucleotide converts huntingtin into huntingtin delta 12. That form resists the cleavage linked to Huntington's disease and keeps the normal function of the protein.

7. 2025

   Huntingtin and plant immunity

   In July 2025, his team, working with groups at the National University of Singapore and the University of Oxford, reports a cryo-EM structure of the DM3 protein complex, which triggers autoimmune responses in plants. In September 2025, a team he leads at KAIST publishes in Science Advances that pairs of huntingtin proteins bundle actin filaments at intervals of about 20 nanometers.

8. As of October 2026

   Key Faculty in AI Transformation

   A KAIST professor since 2009, he is listed as Key Faculty in the Department of AX (AI Transformation), with research areas in molecular machines, gene regulation and neurodegenerative disease. His stated AI competency is understanding complex biological systems using AI as a tool.