JANG,HAGOON

All Publications

• Potential effects of endogenous RNA/DNA hybrids on CRISPR-Cas9-mediated homology-directed repair MOLECULAR THERAPY NUCLEIC ACIDS Puzzo, F., Bayram, B., Macaubas, C., Lin, A., Jang, H., Zhang, F., Mellins, E., Kay, M. A. 2026; 37 (2)

  View details for DOI 10.1016/j.omtn.2026.102880

  View details for Web of Science ID 001722913600001

• Potential effects of endogenous RNA/DNA hybrids on CRISPR-Cas9-mediated homology-directed repair. Molecular therapy. Nucleic acids Puzzo, F., Bayram, B., Macaubas, C., Lin, A., Jang, H., Zhang, F., Mellins, E., Kay, M. A. 2026; 37 (2): 102880

  Abstract

  Recombinant adeno-associated virus (rAAV) vectors and CRISPR-Cas9 are widely used in gene therapy. However, how endogenous DNA secondary structures may potentially affect genome editing outcomes is not fully understood. RNA/DNA hybrids (R-loops), which form mostly during transcription, are dynamically regulated in cells and have been implicated in influencing DNA repair pathway choice. Here, we investigated whether genomic R-loops are associated with differences in Cas9-mediated genome editing outcomes in vitro and in vivo. By targeting regions with relatively low or high R-loop levels within the murine albumin (Alb) and actin (Actb) loci, we observed comparable insertion/deletion (indel) frequencies across sites with different R-loop abundance. In contrast, homology-directed repair (HDR) efficiency appeared reduced at R-loop-enriched sites in proliferating hepatocyte-derived cells (HEPA1-6) but not in quiescent hepatocytes in vivo. Manipulations resulting in reducing R-loop levels, including RNaseH1 overexpression or pharmacological induction of G1 arrest were associated with increased HDR at these genomic sites. In addition, T cell activation correlated with elevated R-loop accumulation suggesting they might influence ex vivo genome editing. Together, these observations suggest that endogenous R-loop levels might influence HDR efficiency during Cas9-mediated editing and is a parameter to consider when designing genome editing strategies.

  View details for DOI 10.1016/j.omtn.2026.102880

  View details for PubMedID 41909468

  View details for PubMedCentralID PMC13022658

• NEAT1 lncRNA Structure-Mediated Functional Modulation as a Novel Therapeutic Approach for MYC-Driven Cancers. Jang, H., Kay, M., Suh, B., Zhang, F. CELL PRESS. 2025

  View details for Web of Science ID 001493880500164

• <i>Tales from the R-loops</i>: how RNA/DNA hybrids may influence CRISPR/Cas9-mediated homologous recombination gene editing outcomes Puzzo, F., Jang, H., Zhang, F., Kay, M. CELL PRESS. 2025

  View details for Web of Science ID 001587763700137

• Screening for Cellular Factors Underlying Mechanisms of AAV Tropism Jang, H., Du, Q., Kay, M. A. CELL PRESS. 2024: 37-38

  View details for Web of Science ID 001332783400070

• Promoterless AAV Gene Targeting Vectors Favor Integration into the Albumin Locus Regardless of Homology Arm Sequences Pekrun, K., Stephens, C., Zhang, F., Jang, H., Puzzo, F., Liehr, P., Goswami, A., Kay, M. A. CELL PRESS. 2023: 738-739

  View details for Web of Science ID 001045144203313

• Fludarabine increases nuclease-free AAV- and CRISPR/Cas9-mediated homologous recombination in mice. Nature biotechnology Tsuji, S., Stephens, C. J., Bortolussi, G., Zhang, F., Baj, G., Jang, H., de Alencastro, G., Muro, A. F., Pekrun, K., Kay, M. A. 2022

  Abstract

  Homologous recombination (HR)-based gene therapy using adeno-associated viruses (AAV-HR) without nucleases has several advantages over classic gene therapy, especially the potential for permanent transgene expression. However, the low efficiency of AAV-HR remains a major limitation. Here, we tested a series of small-molecule compounds and found that ribonucleotide reductase (RNR) inhibitors substantially enhance AAV-HR efficiency in mouse and human liver cell lines approximately threefold. Short-term administration of the RNR inhibitor fludarabine increased the in vivo efficiency of both non-nuclease- and CRISPR/Cas9-mediated AAV-HR two- to sevenfold in the murine liver, without causing overt toxicity. Fludarabine administration induced transient DNA damage signaling in both proliferating and quiescent hepatocytes. Notably, the majority of AAV-HR events occurred in non-proliferating hepatocytes in both fludarabine-treated and control mice, suggesting that the induction of transient DNA repair signaling in non-dividing hepatocytes was responsible for enhancing AAV-HR efficiency in mice. These results suggest that use of a clinically approved RNR inhibitor can potentiate AAV-HR-based genome-editing therapeutics.

  View details for DOI 10.1038/s41587-022-01240-2

  View details for PubMedID 35393561

• Lnc122-The miR122 Precursor Has an Independent Role as a Tumor Suppressor in Liver Jang, H., Chu, K., Zhang, F., Stephens, C., Kay, M. A. CELL PRESS. 2022: 514

  View details for Web of Science ID 000794043702274

• Improved Genome Editing through Inhibition of FANCM and Members of the BTR Dissolvase Complex. Molecular therapy : the journal of the American Society of Gene Therapy de Alencastro, G. n., Puzzo, F. n., Pavel-Dinu, M. n., Zhang, F. n., Pillay, S. n., Majzoub, K. n., Tiffany, M. n., Jang, H. n., Sheikali, A. n., Cromer, M. K., Meetei, R. n., Carette, J. E., Porteus, M. H., Pekrun, K. n., Kay, M. A. 2021; 29 (3): 1016–27

  Abstract

  Recombinant adeno-associated virus (rAAV) vectors have the unique property of being able to perform genomic targeted integration (TI) without inducing a double-strand break (DSB). In order to improve our understanding of the mechanism behind TI mediated by AAV and improve its efficiency, we performed an unbiased genetic screen in human cells using a promoterless AAV-homologous recombination (AAV-HR) vector system. We identified that the inhibition of the Fanconi anemia complementation group M (FANCM) protein enhanced AAV-HR-mediated TI efficiencies in different cultured human cells by ∼6- to 9-fold. The combined knockdown of the FANCM and two proteins also associated with the FANCM complex, RecQ-mediated genome instability 1 (RMI1) and Bloom DNA helicase (BLM) from the BLM-topoisomerase IIIα (TOP3A)-RMI (BTR) dissolvase complex (RMI1, having also been identified in our screen), led to the enhancement of AAV-HR-mediated TI up to ∼17 times. AAV-HR-mediated TI in the presence of a nuclease (CRISPR-Cas9) was also increased by ∼1.5- to 2-fold in FANCM and RMI1 knockout cells, respectively. Furthermore, knockdown of FANCM in human CD34+ hematopoietic stem and progenitor cells (HSPCs) increased AAV-HR-mediated TI by ∼3.5-fold. This study expands our knowledge on the mechanisms related to AAV-mediated TI, and it highlights new pathways that might be manipulated for future improvements in AAV-HR-mediated TI.

  View details for DOI 10.1016/j.ymthe.2020.10.020

  View details for PubMedID 33678249

• A Leu(CAG)-tRNA derived small RNA regulates ribosomal protein S28 after translation initiation in both human and mouse liver cancers Kim, H., Xu, J., Chu, K., Park, H., jang, H., Li, P., Valdmanis, P., Zhang, Q., Kay, M. AMER ASSOC CANCER RESEARCH. 2020

  View details for DOI 10.1158/1538-7445.AM2020-LB-343

  View details for Web of Science ID 000590059302367

• Proteins Complex of the Fanconi Anemia Pathway as Determinant of AAV-Mediated Genomic Targeted Integration Puzzo, F., de Alencastro, G., Pavel-Dinu, M., Zhang, F., Pillay, S., Majzoub, K., Tiffany, M., Jang, H., Sheikali, A., Cromer, K. M., Meetei, R., Carette, J. E., Porteus, M. H., Pekrun, K., Kay, M. A. CELL PRESS. 2020: 459

  View details for Web of Science ID 000530089302154

• A tRNA-Derived Small RNA Regulates Ribosomal Protein S28 Protein Levels after Translation Initiation in Humans and Mice. Cell reports Kim, H. K., Xu, J., Chu, K., Park, H., Jang, H., Li, P., Valdmanis, P. N., Zhang, Q. C., Kay, M. A. 2019; 29 (12): 3816

  Abstract

  tRNA-derived small RNAs (tsRNAs) have been implicated in many cellular processes, yet the detailed mechanisms are not well defined. We previously found that the 3' end of Leu-CAG tRNA-derived small RNA (LeuCAG3'tsRNA) regulates ribosome biogenesis in humans by maintaining ribosomal protein S28 (RPS28) levels. The tsRNA binds to coding (CDS) and non-coding 3' UTR sequence in the RPS28 mRNA, altering its secondary structure and enhancing its translation. Here we report that the functional 3' UTR target site is present in primates while the CDS target site is present in many vertebrates. We establish that this tsRNA also regulates mouse Rps28 translation by interacting with the CDS target site. We further establish that the change in mRNA translation occurred at a post-initiation step in both species. Overall, our results suggest that LeuCAG3'tsRNA might maintain ribosome biogenesis through a conserved gene regulatory mechanism in vertebrates.

  View details for DOI 10.1016/j.celrep.2019.11.062

  View details for PubMedID 31851915

• Amino-Acylated LeuCAG3 ' tsRNA Mediates Translational Elongation of Ribosomal Protein S28 mRNA and is a Key Regulatory Step in Ribosome Biogenesis Kim, H., Liu, Z., Xu, J., Chu, K., Park, H., Jang, H., Li, P., Valdmanis, P., Zhang, Q., Kay, M. CELL PRESS. 2019: 302

  View details for Web of Science ID 000464381003102