Advisor(s)
Anindya Dutta
Eun Young Ahn
Committee Member(s)
Fengbin Wang
Jia Xu
Todd Green
School
Joint Health Sciences (Interdisciplinary)
Document Type
Dissertation
Department (new version)
Genetics
Date of Award
9-11-2025
Abstract
A tumor-suppressive lncRNA DRAIC suppresses tumor migration, invasion and xenograft formation in GBM and prostate cancers. DRAIC interacts with IKKα and NEMO, the two subunits of IKK complex, inhibits the phosphorylation of IkBα. Deletion studies identified that the functional domain located at positions 705-950 DRAIC, however, the relative length impact delivery efficiency. Thereby, defining smaller functional modules of the RNA and protein helps to elucidate the mechanism involved in this interaction and lays the foundation for future efficient delivery into tumor sites. This dissertation aims to identify the minimal regions within DRAIC and IKKα that mediate this interaction. Using SHAPE-MaP, we identified a 36-nt hairpin (A+B) within DRAIC that is necessary and sufficient for its anti-oncogenic function. RNA immunoprecipitation (RIP) and Electrophoretic mobility shift assays (EMSA) confirmed this hairpin physically interacts with the coiled coil domain of IKKα (IKKα-ccd). A+B RNA has a high binding affinity (KD ~1-7 nM) to IKKα. The binding of A+B disrupts the dimerization of NEMO and IKKα-ccd domains in vitro and in vivo, a critical step for IKK action. This is the first time that a demonstration of a short RNA can disrupt coiled-coil dimerization. Consistent with this, A+B inhibits the phosphorylation of IkBα and suppresses NF-kB activity to inhibit tumor oncogenesis Furthermore, the bottom strand of A+B is modulated by alternative splicing that adds a 5’ extension, 4a, to exon 4 of DRAIC and its expression in lung tumors is associated with low NF-kB activity. Additional mutation studies identified that the UUGGAUU in the bottom strand of A+B is required for the interaction with IKKα-ccd. The 4a region is enriched by DNase I, RBM25 and CEBPB. Knocking down RBM 25 and CEBPB altered the ratio of isoforms with and without 4a region in LNCaP cells, accompanied by the alteration of NF-kB target genes, suggesting that RBM25 and CEBPB may play a role in the inclusion of exon 4a-4. In conclusion, we identified a small hairpin A+B that is responsible for DRAIC exerting its function in inhibition of the NF-kB, and UUGGAAU within A+B that is modulated by alternative splicing event is responsible for the interaction.
ProQuest ID
Recommended Citation
Hao, Xiaoxiao, "Explore The Molecular Mechanisms Underlying The Interaction Between The Long Non-Coding Rna Draic And Ikka" (2025). All ETDs from UAB. 7377.
https://digitalcommons.library.uab.edu/etd-collection/7377
