MKRN2 Physically Interacts with GLE1 to Regulate mRNA Export and Zebrafish Retinal Development
Eric J Wolf1, Amanda Miles2, Eliza S Lee3
1Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.
Abstract:
The mammalian mRNA nuclear export process is thought to terminate at the cytoplasmic face of the nuclear pore complex through ribonucleoprotein remodeling. We conduct a stringent affinity-purification mass-spectrometry-based screen of the physical interactions of human RNA-binding E3 ubiquitin ligases. The resulting protein-interaction network reveals interactions between the RNA-binding E3 ubiquitin ligase MKRN2 and GLE1, a DEAD-box helicase activator implicated in mRNA export termination. We assess MKRN2 epistasis with GLE1 in a zebrafish model. Morpholino-mediated knockdown or CRISPR/Cas9-based knockout of MKRN2 partially rescue retinal developmental defects seen upon GLE1 depletion, consistent with a functional association between GLE1 and MKRN2. Using ribonomic approaches, we show that MKRN2 binds selectively to the 3' UTR of a diverse subset of mRNAs and that nuclear export of MKRN2-associated mRNAs is enhanced upon knockdown of MKRN2. Taken together, we suggest that MKRN2 interacts with GLE1 to selectively regulate mRNA nuclear export and retinal development.
Insights
The RNA-binding E3 ubiquitin ligase MKRN2 interacts with GLE1 to regulate messenger RNA (mRNA) nuclear export and retinal development. This finding reveals a novel mechanism controlling gene expression and cellular processes.
Area of Science:
- Molecular Biology
- Cell Biology
- Genetics
Background:
- Messenger RNA (mRNA) nuclear export is crucial for gene expression, involving complex protein interactions at the nuclear pore complex.
- Ribonucleoprotein remodeling is a key step in mRNA export termination.
- The role of RNA-binding E3 ubiquitin ligases in mRNA export is not fully understood.
Purpose of the Study:
- To identify novel protein interactions involved in mammalian mRNA nuclear export.
- To investigate the functional association between MKRN2 and GLE1 in mRNA export and retinal development.
- To elucidate the mechanism by which MKRN2 regulates mRNA export.
Main Methods:
- Affinity-purification mass spectrometry to screen protein interactions of human RNA-binding E3 ubiquitin ligases.
- Zebrafish model to assess epistasis between MKRN2 and GLE1.
- Morpholino-mediated knockdown and CRISPR/Cas9 knockout in zebrafish.
- Ribonomic approaches to identify mRNA targets of MKRN2.
Main Results:
- Identified a physical interaction between MKRN2 and GLE1, an mRNA export factor.
- MKRN2 knockdown or knockout partially rescued retinal defects caused by GLE1 depletion in zebrafish.
- MKRN2 selectively binds to the 3' UTR of a subset of mRNAs.
- Nuclear export of MKRN2-associated mRNAs was enhanced upon MKRN2 knockdown.
Conclusions:
- MKRN2 interacts with GLE1 to selectively regulate mRNA nuclear export.
- This interaction plays a role in retinal development.
- MKRN2 acts as a regulator of mRNA export, influencing gene expression and cellular processes.
