Transactivation-responsive DNA-binding protein 43 (TDP-43) is a component of pathological inclusions in amyotrophic lateral sclerosis and several forms of sporadic and familial frontotemporal lobar degeneration.
To identify novel causes of familial neurodegenerative diseases, we extended our previous studies of TAR DNA-binding protein 43 (TDP-43) proteinopathies to investigate TDP-43 as a candidate gene in familial cases of motor neuron disease.
Since the discovery of neuropathological lesions made of TDP-43 and ubiquitin proteins in cases of frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS), there is a burst of effort on finding related familial mutations and developing animal models.
Inclusions of TAR DNA-binding protein-43 (TDP-43), a nuclear protein that regulates transcription and RNA splicing, are the defining histopathological feature of frontotemporal lobar degeneration with ubiquitin-positive inclusions (FTLD-Us) and sporadic and familial forms of amyotrophic lateral sclerosis (ALS).
Recent studies showed that TAR DNA-binding protein 43 (TDP-43), encoded by the TARDBP gene, is a major pathological protein in both sporadic and familial frontotemporal lobar degeneration (FTLD).
Trans-activation-responsive DNA-binding protein 43 (TDP-43) is a component of pathological inclusions in amyotrophic lateral sclerosis and several forms of sporadic and familial frontotemporal lobar degeneration.
However, emerging research has demonstrated that mutations and pathology associated with the TDP-43 gene and protein may be more common than SOD1 mutations in familial and sporadic ALS.
Mutations in the TARDBP gene, which encodes the TAR DNA binding protein (TDP-43), have been described in individuals with familial and sporadic amyotrophic lateral sclerosis (ALS).
The 43-kD transactive response (TAR)-DNA-binding protein (TARDBP) mutations have been demonstrated to be causative of sporadic and familial forms of amyotrophic lateral sclerosis.
The identification of TDP-43 mutations in familial and sporadic amyotrophic lateral sclerosis cases confirms its pathogenic role; but it is wild-type TDP-43 that is deposited in the vast majority of TDP-43 proteinopathies, implicating other unknown factors for its mislocalization and aggregation.
The RNA/DNA-binding proteins fused in sarcoma (FUS; also known as TLS) and TAR DNA binding protein-43 (TDP-43) have recently been shown to be genetically and pathologically associated with familial forms of ALS and FTD.
Mutations of the progranulin (GRN) gene are a major cause of familial frontotemporal lobar degeneration with transactive response (TAR) DNA-binding protein of 43 kDa (TDP-43) proteinopathy (FTLD-TDP).
For example, FUS and TDP-43, which rank 1st and 10th among RRM-bearing prion candidates, form cytoplasmic inclusions in the degenerating motor neurons of ALS patients and mutations in TDP-43 and FUS cause familial ALS.
French TARDBP+ patients with ALS (n = 28) were compared first to 3 cohorts: 737 sporadic ALS (SALS), 192 nonmutated familial ALS (FALS), and 58 SOD1 + FALS, and then to 117 TARDBP+ cases from the literature.
Overexpression of wild-type TDP-43 resulted in vacuolar degeneration of the photoreceptor neurons associated with thinning of the retina, which was significantly exacerbated by mutations of TDP-43 linked to familial ALS or disrupting its nuclear localization signal (NLS).