Unravelling the molecular basis of fidelity in mRNA splicing through DEAH-box helicases DHX38 and DHX8
Loading...
Embargo End Date
2026-07-15
ICR Authors
Authors
Adde, A
Document Type
Thesis or Dissertation
Date
2026-01-15
Date Accepted
Abstract
The spliceosome is a large and dynamic complex splicing together exons in pre-mRNA to generate mature mRNA, which is then translated into a protein. RNA helicases drive the transitions between different stages of the spliceosome assembly and regulate the selection of a splice junction. This is a normal phenomenon, but when deregulated is a hallmark of cancer. The DEAH-box RNA helicases DHX38 and DHX8 remodel the spliceosome between the C and C* complex and between the C* and P complex at the later stages of spliceosome assembly. They play crucial roles in regulating splicing fidelity by rejecting sub-optimal splice sites. Previous experiments have identified a complex comprising DHX38, DHX8 and other spliceosomal proteins. Using double co-immunoprecipitation, I confirmed that DHX38 and DHX8 co-elute together. Using mass spectrometry, I identified several other spliceosome related proteins involved which I term the ‘fidelity complex’.
DHX38 is a potential therapeutic cancer drug target, as it is upregulated in cancer cells, but the full-length structure is unknown. Therefore, a second aim of my research involved its structure determination using cryo-electron microscopy, because crystallisation of full length DHX38 proved unsuccessful. Here I report a low-resolution anisotropic map of the closed conformation of the full length DHX38. The truncated helicase domain of DHX38 was co-expressed with the novel chaperone NudCD1. NudCD1 is a tumour associated antigen with a conserved p23 domain which allows for chaperone activity. NudCD1 has been found to bind to multiple DEAH-box helicases however its function is still poorly understood. Here I report the low-resolution density maps of NudCD1 on its own, and the NudCD1-DHX38 complex, which shows the WD40 domain of NudCD1 packing against the C-terminal domain of DHX38, with the helicase core in a possible open conformation. Furthermore, the beta sheet of NudCD1 interacting with the RecA domain.
Citation
2026
DOI
Source Title
Publisher
Institute of Cancer Research (University Of London)
ISSN
eISSN
Collections
Research Team
Hit Discov Struct Design