Cryptic Splicing of GAP43 mRNA is a Novel Hallmark of TDP-43-Associated ALS and AD.

ABSTRACT: Cytoplasmic aggregation of transactive response DNA-binding protein 43 (TDP-43) is a hallmark of amyotrophic lateral sclerosis (ALS) and occurs in 57% of Alzheimer's disease (AD) cases. TDP-43 regulates RNA processing, including cryptic exon splicing. Here, we demonstrate that TDP-43 directly controls growth-associated protein (GAP43) expression by binding to its pre-mRNA. Loss or hyperphosphorylation of TDP-43 disrupts this binding, leading to the inclusion of cryptic exon 4a1, which introduces premature stop codons and reduces GAP43 protein levels. RNA sequencing analysis of ALS and AD brains revealed GAP43 downregulation, while 4a1 is upregulated in AD cases with phosphorylated TDP-43. TDP-43 knockdown impaired axonal regeneration in induced pluripotent stem cell (iPSC)-derived motor ne

SUBMITTER: Yang M 

PROVIDER: S-EPMC12463067 | biostudies-literature | 2025 Sep

REPOSITORIES: biostudies-literature