Truncating mutations in THAP1 define the nuclear localization signal

Identification and functional analysis of novel THAP1 mutations

“…THAP1 contains a bipartite NLS spanning 16 amino acids (aa 146-162) in the C-terminal part of THAP1. 18 Although the frameshift mutation Asp191Thrfs*9 does not affect the NLS itself, we demonstrated an impaired nuclear import of mutant THAP1 in vitro. This altered intracellular distribution of THAP1 may be explained by a protein misfolding affecting at least the C-terminal region of THAP1, which disturbs the formation of the bipartite NLS and results in a reduced interaction with nuclear importing proteins.…”

“…These GFP-labeled constructs were transiently expressed for 48 h in OVCAR-3 cells and localization was determined using confocal laser scanning microscopy as described. 18 OVCAR-3 cells are well suited for immunocytochemistry experiments due to their size and handling.…”

“…Recently, in-vitro tests have become available to explore the functional consequences of different mutations. 3,4,18 In the present study, we investigated 567 patients with primary dystonia for mutations in the THAP1 gene and performed an in-vitro assay to assess the putative functional consequences of the mutations. These findings were related to the clinical phenotype of mutation carriers.…”

THAP1, the gene mutated in DYT6 dystonia, autoregulates its own expression

“…Both mutations affect distinct domains of the THAP1 protein: While the missense mutation p.Arg13His is localized in the THAP domain, the frameshift mutation p.Lys158Asnfs*23 disrupts the nuclear localization signal. It has been shown that this mutation impairs the nuclear import of THAP1 preventing DNA binding of cytoplasm-located THAP1 [19]. Thus, both mutations are considered to result in reduced THAP1 promoter binding leading to decreased transcription factor activity and subsequently resulting in reduced repression of THAP1 expression.…”

“…Therefore, we also aimed to investigate endogenous expression levels in patient-derived neurons. Since primary neurons are not available from living individuals, we generated iPS cells from primary human dermal fibroblasts taken from two dystonia patients harboring a heterozygous missense mutation (p.Arg13His) within the THAP DNA-binding domain or a frameshift mutation (p.Lys158Asnfs*23) disrupting the nuclear localization signal of THAP1 [19] as well as two healthy individuals as controls. One iPS cell line per individual was established and the expression of pluripotency markers in these cells was confirmed by immunostaining (Fig.…”