FTLD-MAPT mutations and short 5'UTR Tau mRNAs increase Tau translation

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• Tau protein aggregation is central to Alzheimer's disease (AD) and tauopathies.
• Truncated Tau species and altered expression levels are implicated in disease pathology.
• Mechanisms of truncated Tau synthesis and the role of N-terminal mutations remain unclear.

Purpose of the Study:

• Investigate how Tau mRNA 5' untranslated regions (5'UTRs) and N-terminal mutations influence Tau protein synthesis.
• Elucidate the mechanisms behind truncated Tau generation.
• Determine the impact of disease-associated N-terminal mutations on Tau expression.

Main Methods:

• Analysis of Tau mRNA 5'UTRs in tauopathy brains.
• Investigation of N-terminal Tau coding sequence mutations (R5H, R5L, R5C).
• Assessment of Tau protein synthesis and expression levels in response to mRNA and mutation variations.

Main Results:

• Tau mRNA 5'UTR length and N-terminal coding sequences significantly modulate Tau expression.
• Truncated Tau protein species are produced via alternative translation initiation.
• Disease-associated N-terminal mutations increase Tau expression, primarily through mRNA secondary structure changes.

Conclusions:

• The 5' end of Tau mRNA and N-terminal coding sequences are key regulators of Tau synthesis.
• Alternative translation initiation generates disease-relevant truncated Tau species.
• N-terminal mutations linked to neurodegenerative diseases affect Tau expression through mRNA structural modifications.