TDP-43 regulates its mRNA levels through a negative feedback loop.

Area of Science:

• Molecular Biology
• Neuroscience
• Genetics

Background:

• TAR DNA-binding protein (TDP-43) is an RNA-binding protein implicated in RNA processing.
• Abnormal TDP-43 is a hallmark of neurodegenerative diseases like ALS and FTLD.
• Understanding TDP-43 regulation is critical for disease pathomechanisms.

Purpose of the Study:

• To investigate the regulatory mechanisms controlling TDP-43 expression.
• To determine the role of TDP-43's RNA-binding activity in its own regulation.
• To explore the link between TDP-43 self-regulation and neurodegenerative disease.

Main Methods:

• Generation of human cell lines expressing tagged wild-type and mutant TDP-43.
• Analysis of TDP-43 autoregulation through binding to its 3' UTR.
• Investigation of TDP-43's C-terminal region's role in self-regulation.
• Assessment of TDP-43's impact on mRNA stability and exosome-mediated degradation.

Main Results:

• TDP-43 controls its own expression via a negative feedback loop.
• RNA-binding properties and the C-terminal region of TDP-43 are essential for this autoregulation.
• TDP-43 binding to its 3' UTR promotes RNA instability rather than altering splicing.
• Inhibition of exosome-mediated degradation partially restored TDP-43 levels.

Conclusions:

• Cellular TDP-43 levels are tightly regulated by a negative feedback mechanism.
• Disease-associated TDP-43 aggregates likely disrupt this self-regulation, contributing to pathogenesis.
• TDP-43 autoregulation is a potential therapeutic target for TDP-43 proteinopathies.