TDP-43 promotes microRNA biogenesis as a component of the Drosha and Dicer complexes

Area of Science:

• Molecular Biology
• Neuroscience
• Genetics

Background:

• Aberrant microRNA (miRNA) expression is implicated in various diseases, including cancer.
• The precise mechanisms governing individual miRNA expression remain largely unknown.
• Abnormal cellular distribution of TAR DNA-binding protein-43 (TDP-43) is a hallmark of neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD).

Purpose of the Study:

• To elucidate the role of TDP-43 in microRNA (miRNA) biogenesis.
• To investigate the mechanisms by which TDP-43 regulates miRNA production.
• To determine the functional significance of TDP-43 in miRNA processing and neuronal development.

Main Methods:

• Investigated TDP-43 interactions with the Drosha and Dicer complexes.
• Analyzed TDP-43 binding to primary miRNAs (pri-miRNAs) and precursor miRNAs (pre-miRNAs).
• Assessed the impact of TDP-43 on miRNA biogenesis and neuronal outgrowth.

Main Results:

• TDP-43 facilitates precursor miRNA (pre-miRNA) production by interacting with the nuclear Drosha complex and binding to primary miRNAs (pri-miRNAs).
• Cytoplasmic TDP-43 promotes pre-miRNA processing through interaction with the Dicer complex and binding to pre-miRNA terminal loops.
• TDP-43's role in miRNA biogenesis is critical for neuronal outgrowth.

Conclusions:

• TDP-43 plays a previously unrecognized role in the posttranscriptional regulation of miRNA expression.
• TDP-43 regulates miRNA biogenesis in both the nucleus and the cytoplasm.
• Dysregulation of TDP-43 in miRNA biogenesis may contribute to neurodegenerative diseases.