Structural determinants of specific DNA-recognition by the THAP zinc finger

Bioinformatic analysis of THAP9 transposase homolog: conserved regions, novel motifs

THAP9 is a transposable element-derived gene that encodes the THAP9 protein, which is homologous to the Drosophila P-element transposase (DmTNP) and can cut and paste DNA. However, the exact functional role of THAP9 is unknown. Here, we perform structure prediction, evolutionary analysis and extensive in silico characterization of THAP9, including predicting domains and putative post-translational modification sites. Comparison of the AlphaFold-predicted structure of THAP9 with the DmTNP CryoEM structure, provided insights about the C2CH motif and other DNA binding residues, RNase H-like catalytic domain and insertion domain of the THAP9 protein. We also predicted previously unreported mammalian-specific post-translational modification sites that may play a role in the subcellular localization of THAP9. Furthermore, we observed that there are distinct organism class-specific conservation patterns of key functional residues in certain THAP9 domains.

Transcriptional regulatory network for neuron-glia interactions and its implication for DYT6 dystonia

Advances in sequencing technologies have identified novel genes associated with inherited forms of dystonia, providing valuable insights into its genetic basis and revealing diverse genetic pathways and mechanisms involved in its pathophysiology. Since identifying genetic variation in the transcription factor coding THAP1 gene linked to isolated dystonia, numerous investigations have employed transcriptomic studies in DYT-THAP1 models to uncover pathogenic molecular mechanisms underlying dystonia. This review examines key findings from transcriptomic studies conducted on in vivo and in vitro DYT-THAP1 models, which demonstrate that the THAP1-regulated transcriptome is diverse and cell-specific, yet it is bound and co-regulated by a common set of proteins. Prominent among its functions, THAP1 and its co-regulatory network target molecular pathways critical for generating myelinating oligodendrocytes that ensheath axons and generate white matter in the central nervous system. Several lines of investigation have demonstrated the importance of myelination and oligodendrogenesis in motor function during development and in adults, emphasizing the non-cell autonomous contributions of glial cells to neural circuits involved in motor function. Further research on the role of myelin abnormalities in motor deficits in DYT6 models will enhance our understanding of axon-glia interactions in dystonia pathophysiology and provide potential therapeutic interventions targeting these pathways.

Versatile Strategy for the Construction of a Transcription Factor-Based Orthogonal Gene Expression Toolbox in Monascus spp

Gene expression is needed to be conducted in an orthogonal manner and controllable independently from the host's native regulatory system. However, there is a shortage of gene expression regulatory toolboxes that function orthogonally from each other and toward the host. Herein, we developed a strategy based on the mutant library to generate orthogonal gene expression toolboxes. A transcription factor, MaR, located in the Monascus azaphilone biosynthetic gene cluster, was taken as a typical example. Nine DNA-binding residues of MaR were identified by molecular simulation and site-directed mutagenesis. We created five MaR multi-site saturation mutagenesis libraries consisting of 10743 MaR variants on the basis of five cognate promoters. A functional analysis revealed that all five tested promoters were orthogonally regulated by five different MaR variants, respectively. Furthermore, fine gene expression tunability and high signal sensitivity of this toolbox are demonstrated by introducing chemically inducible expression modules, designing synthetic promoter elements, and creating protein-protein interaction between MaRs. This study paves the way for a bottom-up approach to build orthogonal gene expression toolboxes.

Pan-Cancer Analysis Reveals the Prognostic Potential of the THAP9/THAP9-AS1 Sense-Antisense Gene Pair in Human Cancers

Human THAP9, which encodes a domesticated transposase of unknown function, and lncRNA THAP9-AS1 (THAP9-antisense1) are arranged head-to-head on opposite DNA strands, forming a sense and antisense gene pair. We predict that there is a bidirectional promoter that potentially regulates the expression of THAP9 and THAP9-AS1. Although both THAP9 and THAP9-AS1 are reported to be involved in various cancers, their correlative roles on each other’s expression has not been explored. We analyzed the expression levels, prognosis, and predicted biological functions of the two genes across different cancer datasets (TCGA, GTEx). We observed that although the expression levels of the two genes, THAP9 and THAP9-AS1, varied in different tumors, the expression of the gene pair was strongly correlated with patient prognosis; higher expression of the gene pair was usually linked to poor overall and disease-free survival. Thus, THAP9 and THAP9-AS1 may serve as potential clinical biomarkers of tumor prognosis. Further, we performed a gene co-expression analysis (using WGCNA) followed by a differential gene correlation analysis (DGCA) across 22 cancers to identify genes that share the expression pattern of THAP9 and THAP9-AS1. Interestingly, in both normal and cancer samples, THAP9 and THAP9-AS1 often co-express; moreover, their expression is positively correlated in each cancer type, suggesting the coordinated regulation of this H2H gene pair.

A pathogenic DYT-THAP1 dystonia mutation causes hypomyelination and loss of YY1 binding

Dystonia is a disabling disease that manifests as prolonged involuntary twisting movements. DYT-THAP1 is an inherited form of isolated dystonia caused by mutations in THAP1 encoding the transcription factor THAP1. The phe81leu (F81L) missense mutation is representative of a category of poorly understood mutations that do not occur on residues critical for DNA binding. Here, we demonstrate that the F81L mutation (THAP1F81L) impairs THAP1 transcriptional activity and disrupts CNS myelination. Strikingly, THAP1F81L exhibits normal DNA binding but causes a significantly reduced DNA binding of YY1, its transcriptional partner that also has an established role in oligodendrocyte lineage progression. Our results suggest a model of molecular pathogenesis whereby THAP1F81L normally binds DNA but is unable to efficiently organize an active transcription complex.

Dystonia-specific mutations in THAP1 alter transcription of genes associated with neurodevelopment and myelin

Dystonia is a neurologic disorder associated with an increasingly large number of genetic variants in many genes, resulting in characteristic disturbances in volitional movement. Dissecting the relationships between these mutations and their functional outcomes is critical in understanding the pathways that drive dystonia pathogenesis. Here we established a pipeline for characterizing an allelic series of dystonia-specific mutations. We used this strategy to investigate the molecular consequences of genetic variation in THAP1, which encodes a transcription factor linked to neural differentiation. Multiple pathogenic mutations associated with dystonia cluster within distinct THAP1 functional domains and are predicted to alter DNA-binding properties and/or protein interactions differently, yet the relative impact of these varied changes on molecular signatures and neural deficits is unclear. To determine the effects of these mutations on THAP1 transcriptional activity, we engineered an allelic series of eight alterations in a common induced pluripotent stem cell background and differentiated these lines into a panel of near-isogenic neural stem cells (n = 94 lines). Transcriptome profiling followed by joint analysis of the most robust signatures across mutations identified a convergent pattern of dysregulated genes functionally related to neurodevelopment, lysosomal lipid metabolism, and myelin. On the basis of these observations, we examined mice bearing Thap1-disruptive alleles and detected significant changes in myelin gene expression and reduction of myelin structural integrity relative to control mice. These results suggest that deficits in neurodevelopment and myelination are common consequences of dystonia-associated THAP1 mutations and highlight the potential role of neuron-glial interactions in the pathogenesis of dystonia.

Transposable elements shape the evolution of mammalian development

Transposable elements (TEs) promote genetic innovation but also threaten genome stability. Despite multiple layers of host defence, TEs actively shape mammalian-specific developmental processes, particularly during pre-implantation and extra-embryonic development and at the maternal-fetal interface. Here, we review how TEs influence mammalian genomes both directly by providing the raw material for genetic change and indirectly via co-evolving TE-binding Krüppel-associated box zinc finger proteins (KRAB-ZFPs). Throughout mammalian evolution, individual activities of ancient TEs were co-opted to enable invasive placentation that characterizes live-born mammals. By contrast, the widespread activity of evolutionarily young TEs may reflect an ongoing co-evolution that continues to impact mammalian development.

4-Methylumbelliferone treatment and hyaluronan inhibition as a therapeutic strategy for chronic prostatitis

BACKGROUND

Hyaluronan (HA), an extracellular matrix component, accumulates in most chronic inflammatory tissues. Here, we studied the impact of HA on the pathogenesis of chronic prostatitis.

MATERIALS AND METHODS

First, we sorted demographic characteristics and peripheral blood serum samples from patients with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) to assess the relationship between the levels of HA in peripheral blood serum and the severity of inflammation in patients. Second, we induced an experimental autoimmune prostatitis (EAP) mouse model and treated the mice with 4-methylumbelliferone (4-MU) (200 mg/kg/day). After the mice were sacrificed, RNA from Th1 cells of the mouse spleens was extracted for RNA sequencing. We used weighted gene co-expression network analysis (WGCNA) to identify co-expressed gene modules and hub-gene related to the pathogenesis of EAP. The expression of critical genes associated with the identified pathway was confirmed by using western blot analysis.

RESULTS

HA was significantly more highly expressed in CP/CPPS patients than in healthy volunteers and positively correlated with the severity of pain, urination symptoms, and quality of life. Besides, the protein expression of HA was significantly higher in prostate tissues derived from EAP models than in those derived from controls. 4-MU, an oral inhibitor of HA synthesis, relieved immunocyte infiltration to the prostate and significantly reduced the proportion of Th1 cells. Based on the WGCNA, we identified 18 co-expression modules and identified that the Grey60 and brown modules were positively associated with the EAP and negatively associated with the Control and 4-MU-treated groups. Pathway enrichment analyses and western blot assays proved that HA potentially activated the cell cycle pathway, increasing the proportion of Th1 cells promoting chronic prostatitis pathogenesis, while these processes were reversed by 4-MU treatment.

CONCLUSIONS

Our results suggest that HA is elevated in patients with CP/CPPS compared with healthy controls and that targeting HA through 4-MU suppresses the activity of the cell cycle-related pathway, potentially by decreasing the proportion of Th1 cells and relieving chronic prostatitis. Our findings might inspire the clinical treatment of chronic prostatitis.

Reduced Expression of GABA A Receptor Alpha2 Subunit Is Associated With Disinhibition of DYT-THAP1 Dystonia Patient-Derived Striatal Medium Spiny Neurons

DYT-THAP1 dystonia (formerly DYT6) is an adolescent-onset dystonia characterized by involuntary muscle contractions usually involving the upper body. It is caused by mutations in the gene THAP1 encoding for the transcription factor Thanatos-associated protein (THAP) domain containing apoptosis-associated protein 1 and inherited in an autosomal-dominant manner with reduced penetrance. Alterations in the development of striatal neuronal projections and synaptic function are known from transgenic mice models. To investigate pathogenetic mechanisms, human induced pluripotent stem cell (iPSC)-derived medium spiny neurons (MSNs) from two patients and one family member with reduced penetrance carrying a mutation in the gene THAP1 (c.474delA and c.38G > A) were functionally characterized in comparison to healthy controls. Calcium imaging and quantitative PCR analysis revealed significantly lower Ca²⁺ amplitudes upon GABA applications and a marked downregulation of the gene encoding the GABA_A receptor alpha2 subunit in THAP1 MSNs indicating a decreased GABAergic transmission. Whole-cell patch-clamp recordings showed a significantly lower frequency of miniature postsynaptic currents (mPSCs), whereas the frequency of spontaneous action potentials (APs) was elevated in THAP1 MSNs suggesting that decreased synaptic activity might have resulted in enhanced generation of APs. Our molecular and functional data indicate that a reduced expression of GABA_A receptor alpha2 subunit could eventually lead to limited GABAergic synaptic transmission, neuronal disinhibition, and hyperexcitability of THAP1 MSNs. These data give pathophysiological insight and may contribute to the development of novel treatment strategies for DYT-THAP1 dystonia.

THAP11 Functions as a Tumor Suppressor in Gastric Cancer through Regulating c-Myc Signaling Pathways

We aim to investigate the role of THAP11 (thanatos-associated protein11) in gastric cancer and its regulation mechanisms. THAP11 expression was analyzed in 51 pairs of GC tissues and the corresponding paracancerous tissues by qRT-PCR and Western blot. After THAP11 was overexpressed or knocked-down, cell proliferation, cell cycle, and apoptosis were detected in MKN-45 cells. We found that THAP11 was significantly downregulated in GC tissues and GC cell lines. Functionally, THAP11 overexpression markedly inhibited cell growth, induced G1/G0 cell-cycle arrest, and promoted cell apoptosis of MKN-45 cells, while silencing of THAP11 led to increased cell growth, increased DNA synthesis, and inhibited apoptosis. In addition, THAP11 negatively regulated the expression of c-Myc, decreased cyclinD1 protein, and increased p27 and p21 protein levels. We also found cell growth suppression induced by THAP11 was rescued by c-Myc overexpression, further confirming that THAP11 suppresses gastric cancer cell growth via the c-Myc pathway. THAP11 acts as a cell growth suppressor and exerts its role possibly through negatively regulating c-Myc pathway in gastric cancer.

Classification of the human THAP protein family identifies an evolutionarily conserved coiled coil region

Background

The THAP (Thanatos Associated Proteins) protein family in humans is implicated in various important cellular processes like epigenetic regulation, maintenance of pluripotency, transposition and disorders like cancers and hemophilia. The human THAP protein family which consists of twelve members of different lengths has a well characterized amino terminal, zinc-coordinating, DNA-binding domain called the THAP domain. However, the carboxy terminus of most THAP proteins is yet to be structurally characterized. A coiled coil region is known to help in protein oligomerization in THAP1 and THAP11. It is not known if other human THAP proteins oligomerize. We have used bioinformatic tools to explore the possibility of dimerization of THAP proteins via a coiled coil region.

Results

Classification of human THAP protein into three size based groups led to the identification of an evolutionarily conserved alpha helical region, downstream of the amino terminal THAP domain. Secondary structure predictions, alpha helical wheel plots and protein models demonstrated the strong possibility of coiled coil formation in this conserved, leucine rich region of all THAP proteins except THAP10.

Conclusions

The identification of a predicted oligomerization region in the human THAP protein family opens new directions to investigate the members of this protein family.

Electronic supplementary material

The online version of this article (10.1186/s12900-019-0102-2) contains supplementary material, which is available to authorized users.

The Human Transcription Factors

Transcription factors (TFs) recognize specific DNA sequences to control chromatin and transcription, forming a complex system that guides expression of the genome. Despite keen interest in understanding how TFs control gene expression, it remains challenging to determine how the precise genomic binding sites of TFs are specified and how TF binding ultimately relates to regulation of transcription. This review considers how TFs are identified and functionally characterized, principally through the lens of a catalog of over 1,600 likely human TFs and binding motifs for two-thirds of them. Major classes of human TFs differ markedly in their evolutionary trajectories and expression patterns, underscoring distinct functions. TFs likewise underlie many different aspects of human physiology, disease, and variation, highlighting the importance of continued effort to understand TF-mediated gene regulation.

Inherited dystonias: clinical features and molecular pathways

Recent decades have witnessed dramatic increases in understanding of the genetics of dystonia - a movement disorder characterized by involuntary twisting and abnormal posture. Hampered by a lack of overt neuropathology, researchers are investigating isolated monogenic causes to pinpoint common molecular mechanisms in this heterogeneous disease. Evidence from imaging, cellular, and murine work implicates deficiencies in dopamine neurotransmission, transcriptional dysregulation, and selective vulnerability of distinct neuronal populations to disease mutations. Studies of genetic forms of dystonia are also illuminating the developmental dependence of disease symptoms that is typical of many forms of the disease. As understanding of monogenic forms of dystonia grows, a clearer picture will develop of the abnormal motor circuitry behind this relatively common phenomenology. This chapter focuses on the current data covering the etiology and epidemiology, clinical presentation, and pathogenesis of four monogenic forms of isolated dystonia: DYT-TOR1A, DYT-THAP1, DYT-GCH1, and DYT-GNAL.

The DYT6 Dystonia Protein THAP1 Regulates Myelination within the Oligodendrocyte Lineage

The childhood-onset motor disorder DYT6 dystonia is caused by loss-of-function mutations in the transcription factor THAP1, but the neurodevelopmental processes in which THAP1 participates are unknown. We find that THAP1 is essential for the timing of myelination initiation during CNS maturation. Conditional deletion of THAP1 in the CNS retards maturation of the oligodendrocyte (OL) lineage, delaying myelination and causing persistent motor deficits. The CNS myelination defect results from a cell-autonomous requirement for THAP1 in the OL lineage and is recapitulated in developmental assays performed on OL progenitor cells purified from Thap1 null mice. Loss of THAP1 function disrupts a core set of OL maturation genes and reduces the DNA occupancy of YY1, a transcription factor required for OL maturation. These studies establish a role for THAP1 transcriptional regulation at the inception of myelination and implicate abnormal timing of myelination in the pathogenesis of childhood-onset dystonia.

Genomic Determinants of THAP11/ZNF143/HCFC1 Complex Recruitment to Chromatin

The THAP11 and ZNF143 transcription factors recognize overlapping DNA sequences and are reported to exhibit signs of both competitive and cooperative binding. HCFC1 serves as a scaffold protein, bridging interactions between transcription factors, including THAP11 and ZNF143, and transcriptional coregulators. The exact mechanism of how DNA sequences guide the recruitment of the THAP11/ZNF143/HCFC1 complex to chromatin is still controversial. In this study, we use chromosomally integrated synthetic constructs and clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9-mediated approaches in intact cells to elucidate the role of the DNA sequence in the recruitment of this complex and to establish its biological relevance. We show that the ACTACA submotif, shared by both THAP11 and ZNF143, directs the recruitment of THAP11 and HCFC1 to ZNF143-occupied loci. Importantly, its position, spacing, and orientation relative to the ZNF143 core motif are critical for this action. CRISPR-Cas9-mediated alterations of the ACTACA submotif at endogenous promoters recapitulated results obtained with synthetic constructs and resulted in altered gene transcription and histone modifications at targeted promoters. Our in vivo approaches provide strong evidence for the molecular role of the ACTACA submotif in THAP11, ZNF143, and HCFC1 cooperative recruitment to chromatin and its biological role in target gene expression.

P Transposable Elements in Drosophila and other Eukaryotic Organisms

P transposable elements were discovered in Drosophila as the causative agents of a syndrome of genetic traits called hybrid dysgenesis. Hybrid dysgenesis exhibits a unique pattern of maternal inheritance linked to the germline-specific small RNA piwi-interacting (piRNA) pathway. The use of P transposable elements as vectors for gene transfer and as genetic tools revolutionized the field of Drosophila molecular genetics. P element transposons have served as a useful model to investigate mechanisms of cut-and-paste transposition in eukaryotes. Biochemical studies have revealed new and unexpected insights into how eukaryotic DNA-based transposons are mobilized. For example, the P element transposase makes unusual 17nt-3' extended double-strand DNA breaks at the transposon termini and uses guanosine triphosphate (GTP) as a cofactor to promote synapsis of the two transposon ends early in the transposition pathway. The N-terminal DNA binding domain of the P element transposase, called a THAP domain, contains a C2CH zinc-coordinating motif and is the founding member of a large family of animal-specific site-specific DNA binding proteins. Over the past decade genome sequencing efforts have revealed the presence of P element-like transposable elements or P element transposase-like genes (called THAP9) in many eukaryotic genomes, including vertebrates, such as primates including humans, zebrafish and Xenopus, as well as the human parasite Trichomonas vaginalis, the sea squirt Ciona, sea urchin and hydra. Surprisingly, the human and zebrafish P element transposase-related THAP9 genes promote transposition of the Drosophila P element transposon DNA in human and Drosophila cells, indicating that the THAP9 genes encode active P element "transposase" proteins.

Host cell factor-1 recruitment to E2F-bound and cell-cycle-control genes is mediated by THAP11 and ZNF143

Host cell factor-1 (HCF-1) is a metazoan transcriptional coregulator essential for cell-cycle progression and cell proliferation. Current models suggest a mechanism whereby HCF-1 functions as a direct coregulator of E2F proteins, facilitating the expression of genes necessary for cell proliferation. In this report, we show that HCF-1 recruitment to numerous E2F-bound promoters is mediated by the concerted action of zinc finger transcription factors THAP11 and ZNF143, rather than E2F proteins directly. THAP11, ZNF143, and HCF-1 form a mutually dependent complex on chromatin, which is independent of E2F occupancy. Disruption of the THAP11/ZNF143/HCF-1 complex results in altered expression of cell-cycle control genes and leads to reduced cell proliferation, cell-cycle progression, and cell viability. These data establish a model in which a THAP11/ZNF143/HCF-1 complex is a critical component of the transcriptional regulatory network governing cell proliferation.

Dystonia type 6 gene product Thap1: identification of a 50 kDa DNA-binding species in neuronal nuclear fractions

Mutations in THAP1 result in dystonia type 6, with partial penetrance and variable phenotype. The goal of this study was to examine the nature and expression pattern of the protein product(s) of the Thap1 transcription factor (DYT6 gene) in mouse neurons, and to study the regional and developmental distribution, and subcellular localization of Thap1 protein. The goal was accomplished via overexpression and knock-down of Thap1 in the HEK293T cell line and in mouse striatal primary cultures and western blotting of embryonic Thap1-null tissue. The endogenous and transduced Thap1 isoforms were characterized using three different commercially available anti-Thap1 antibodies and validated by immunoprecipitation and DNA oligonucleotide affinity chromatography. We identified multiple, novel Thap1 species of apparent M_r 32 kDa, 47 kDa, and 50–52 kDa in vitro and in vivo, and verified the previously identified species at 29–30 kDa in neurons. The Thap1 species at the 50 kDa size range was exclusively detected in murine brain and testes and were located in the nuclear compartment. Thus, in addition to the predicted 25 kDa apparent M_r, we identified Thap1 species with greater apparent M_r that we speculate may be a result of posttranslational modifications. The neural localization of the 50 kDa species and its nuclear compartmentalization suggests that these may be key Thap1 species controlling neuronal gene transcription. Dysfunction of the neuronal 50 kDa species may therefore be implicated in the pathogenesis of DYT6.

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

THAP1 encodes a transcription factor but its regulation is largely elusive. TOR1A was shown to be repressed by THAP1 in vitro. Notably, mutations in both of these genes lead to dystonia (DYT6 or DYT1). Surprisingly, expressional changes of TOR1A in THAP1 mutation carriers have not been detected indicating additional levels of regulation. Here, we investigated whether THAP1 is able to autoregulate its own expression. Using in-silico prediction, luciferase reporter gene assays, and (quantitative) chromatin immunoprecipitation (ChIP), we defined the THAP1 minimal promoter to a 480bp-fragment and demonstrated specific binding of THAP1 to this region which resulted in repression of the THAP1 promoter. This autoregulation was disturbed by different DYT6-causing mutations. Two mutants (Ser6Phe, Arg13His) were shown to be less stable than wildtype THAP1 adding to the effect of reduced binding to the THAP1 promoter. Overexpressed THAP1 is preferably degraded through the proteasome. Notably, endogenous THAP1 expression was significantly reduced in cells overexpressing wildtype THAP1 as demonstrated by quantitative PCR. In contrast, higher THAP1 levels were detected in induced pluripotent stem cell (iPS)-derived neurons from THAP1 mutation carriers. Thus, we identified a feedback-loop in the regulation of THAP1 expression and demonstrated that mutant THAP1 leads to higher THAP1 expression levels. This compensatory autoregulation may contribute to the mean age at onset in the late teen years or even reduced penetrance in some THAP1 mutation carriers.

Combined occurrence of a novel TOR1A and a THAP1 mutation in primary dystonia

BACKGROUND

The ΔGAG deletion of the TOR1A gene (DYT1) is responsible for DYT1 dystonia. However, no other TOR1A mutation has been reported in the Chinese population.

METHODS

Two hundred one dystonia patients without the ΔGAG deletion were screened for other mutations in TOR1A. Gene function changes were analyzed by subcellular distribution and luciferase reporter assay.

RESULTS

A novel TOR1A mutation (c.581A>T, p.Asp194Val) was found in a patient with early-onset segmental dystonia harboring a THAP1 mutation (c.539T>C, p.Leu180Ser). Overexpression of mutant TOR1A Asp194Val protein induces inclusion formation in SK-N-AS cell lines, and the repressive activity of the mutant THAP1 Leu180Ser protein on TOR1A gene expression is decreased compared with wild-type THAP1.

CONCLUSIONS

This is the first report about a dystonia patient harboring two distinct dystonia gene mutations. Functional analysis indicated a potential additive effect of these two mutations, which might provoke the occurrence of dystonic symptoms in this patient.

Effects of THAP11 on erythroid differentiation and megakaryocytic differentiation of K562 cells

Hematopoiesis is a complex process regulated by sets of transcription factors in a stage-specific and context-dependent manner. THAP11 is a transcription factor involved in cell growth, ES cell pluripotency, and embryogenesis. Here we showed that THAP11 was down-regulated during erythroid differentiation but up-regulated during megakaryocytic differentiation of cord blood CD34+ cells. Overexpression of THAP11 in K562 cells inhibited the erythroid differentiation induced by hemin with decreased numbers of benzidine-positive cells and decreased mRNA levels of α-globin (HBA) and glycophorin A (GPA), and knockdown of THAP11 enhanced the erythroid differentiation. Conversely, THAP11 overexpression accelerated the megakaryocytic differentiation induced by phorbol myristate acetate (PMA) with increased percentage of CD41+ cells, increased numbers of 4N cells, and elevated CD61 mRNA levels, and THAP11 knockdown attenuated the megakaryocytic differentiation. The expression levels of transcription factors such as c-Myc, c-Myb, GATA-2, and Fli1 were changed by THAP11 overexpression. In this way, our results suggested that THAP11 reversibly regulated erythroid and megakaryocytic differentiation.

Emerging common molecular pathways for primary dystonia

The dystonias are a group of hyperkinetic movement disorders whose principal cause is neuron dysfunction at 1 or more interconnected nodes of the motor system. The study of genes and proteins that cause familial dystonia provides critical information about the cellular pathways involved in this dysfunction, which disrupts the motor pathways at the systems level. In recent years study of the increasing number of DYT genes has implicated a number of cell functions that appear to be involved in the pathogenesis of dystonia. A review of the literature published in English-language publications available on PubMed relating to the genetics and cellular pathology of dystonia was performed. Numerous potential pathogenetic mechanisms have been identified. We describe those that fall into 3 emerging thematic groups: cell-cycle and transcriptional regulation in the nucleus, endoplasmic reticulum and nuclear envelope function, and control of synaptic function. © 2013 Movement Disorder Society.

A rare sequence variant in intron 1 of THAP1 is associated with primary dystonia

Although coding variants in THAP1 have been causally associated with primary dystonia, the contribution of noncoding variants remains uncertain. Herein, we examine a previously identified Intron 1 variant (c.71+9C>A, rs200209986). Among 1672 subjects with mainly adult-onset primary dystonia, 12 harbored the variant in contrast to 1/1574 controls (P < 0.01). Dystonia classification included cervical dystonia (N = 3), laryngeal dystonia (adductor subtype, N = 3), jaw-opening oromandibular dystonia (N = 1), blepharospasm (N = 2), and unclassified (N = 3). Age of dystonia onset ranged from 25 to 69 years (mean = 54 years). In comparison to controls with no identified THAP1 sequence variants, the c.71+9C>A variant was associated with an elevated ratio of Isoform 1 (NM_018105) to Isoform 2 (NM_199003) in leukocytes. In silico and minigene analyses indicated that c.71+9C>A alters THAP1 splicing. Lymphoblastoid cells harboring the c.71+9C>A variant showed extensive apoptosis with relatively fewer cells in the G2 phase of the cell cycle. Differentially expressed genes from lymphoblastoid cells revealed that the c.71+9C>A variant exerts effects on DNA synthesis, cell growth and proliferation, cell survival, and cytotoxicity. In aggregate, these data indicate that THAP1 c.71+9C>A is a risk factor for adult-onset primary dystonia.

Par-4/THAP1 complex and Notch3 competitively regulated pre-mRNA splicing of CCAR1 and affected inversely the survival of T-cell acute lymphoblastic leukemia cells

Although the intensification of therapy for children with T-cell acute lymphoblastic leukemia (T-ALL) has substantially improved clinical outcomes, T-ALL remains an important challenge in pediatric oncology. Here, we report that the cooperative synergy between prostate apoptosis response factor-4 (Par-4) and THAP1 induces cell cycle and apoptosis regulator 1 (CCAR1) gene expression and cellular apoptosis in human T-ALL cell line Jurkat cells, CEM cells and primary cultured neoplastic T lymphocytes from children with T-ALL. Par-4 and THAP1 collaborated to activate the promoter of CCAR1 gene. Mechanistic investigations revealed that Par-4 and THAP1 formed a protein complex by the interaction of their carboxyl termini, and THAP1 bound to CCAR1 promoter though its zinc-dependent DNA-binding domain at amino terminus. Par-4/THAP1 complex and Notch3 competitively bound to CCAR1 promoter and competitively modulated alternative pre-mRNA splicing of CCAR1, which resulted in two different transcripts and played an opposite role in T-ALL cell survival. Despite Notch3 induced a shift splicing from the full-length isoform toward a shorter form of CCAR1 mRNA by splicing factor SRp40 and SRp55, Par-4/THAP1 complex strongly antagonized this inductive effect. Our finding revealed a mechanistic rationale for Par-4/THAP1-induced apoptosis in T-ALL cells that would be of benefit to develop a new therapy strategy for T-ALL.

Identification of multiple binding sites for the THAP domain of the Galileo transposase in the long terminal inverted-repeats

Galileo is a DNA transposon responsible for the generation of several chromosomal inversions in Drosophila. In contrast to other members of the P-element superfamily, it has unusually long terminal inverted-repeats (TIRs) that resemble those of Foldback elements. To investigate the function of the long TIRs we derived consensus and ancestral sequences for the Galileo transposase in three species of Drosophilids. Following gene synthesis, we expressed and purified their constituent THAP domains and tested their binding activity towards the respective Galileo TIRs. DNase I footprinting located the most proximal DNA binding site about 70 bp from the transposon end. Using this sequence we identified further binding sites in the tandem repeats that are found within the long TIRs. This suggests that the synaptic complex between Galileo ends may be a complicated structure containing higher-order multimers of the transposase. We also attempted to reconstitute Galileo transposition in Drosophila embryos but no events were detected. Thus, although the limited numbers of Galileo copies in each genome were sufficient to provide functional consensus sequences for the THAP domains, they do not specify a fully active transposase. Since the THAP recognition sequence is short, and will occur many times in a large genome, it seems likely that the multiple binding sites within the long, internally repetitive, TIRs of Galileo and other Foldback-like elements may provide the transposase with its binding specificity.

NMR studies of a new family of DNA binding proteins: the THAP proteins

The THAP (THanatos-Associated Protein) domain is an evolutionary conserved C2CH zinc-coordinating domain shared with a large family of cellular factors (THAP proteins). Many members of the THAP family act as transcription factors that control cell proliferation, cell cycle progression, angiogenesis, apoptosis and epigenetic gene silencing. They recognize specific DNA sequences in the promoters of target genes and subsequently recruit effector proteins. Recent structural and functional studies have allowed getting better insight into the nuclear and cellular functions of some THAP members and the molecular mechanisms by which they recognize DNA. The present article reviews recent advances in the knowledge of the THAP domains structures and their interaction with DNA, with a particular focus on NMR. It provides the solution structure of the THAP domain of THAP11, a recently characterized human THAP protein with important functions in transcription and cell growth in colon cancer.

Pathologic changes in the brain in cervical dystonia pre- and post-mortem - a commentary with a special focus on the cerebellum

In a recent issue of Experimental Neurology, Prudente et al. (2012) investigated the neuropathology of cervical dystonia in six patients. Their most important finding was a patchy loss of cerebellar Purkinje cells in the cerebellum. In this article we discuss their findings in the context of a review including primary and secondary cervical dystonia. An update is given of the current knowledge on structural and functional brain abnormalities in idiopathic cervical dystonia with a special focus on the cerebellum.

Neural expression of the transcription factor THAP1 during development in rat

Loss of function mutations in THAP1 has been associated with primary generalized and focal dystonia in children and adults. THAP1 encodes a transcription factor (THAP1) that harbors an atypical zinc finger domain and plays a critical role in G(1)-S cell cycle control. Current thinking suggests that dystonia may be a neurodevelopmental circuit disorder. Hence, THAP1 may participate in the development of the nervous system. Herein, we report the neurodevelopmental expression patterns of Thap1 transcript and THAP1 protein from the early postnatal period through adulthood in the rat brain, spinal cord and dorsal root ganglia (DRG). We detected Thap1 transcript and THAP1-immunoreactivity (IR) in the cerebral cortex, cerebellum, striatum, substantia nigra, thalamus, spinal cord and DRG. Thap1 transcript expression was higher in the brain than in spinal cord and DRG at P1 and P7 and declined to similar levels at P14 and later time points in all regions except the cerebellum, where it remained high through adulthood. In the brain, THAP1 expression was highest in early development, particularly in the cerebellum at P7. In addition to Purkinje cells in the cerebellum, THAP1-IR was also localized to pyramidal neurons in the cerebral cortex, relay neurons in the thalamus, medium spiny and cholinergic neurons in the striatum, dopaminergic neurons in the substantia nigra, and pyramidal and interneurons in the hippocampus. In the cerebellar cortex, THAP1-IR was prominently distributed in the perikarya and proximal dendrites of Purkinje cells at early time-points. In contrast, it was more diffusely distributed throughout the dendritic arbor of adult Purkinje cells producing a moderate diffuse staining pattern in the molecular layer. At all time points, nuclear IR was weaker than cytoplasmic IR. The prominent cytoplasmic and developmentally regulated expression of THAP1 suggests that THAP1 may function as part of a cell surface-nucleus signaling cascade involved in terminal neural differentiation.

THAP and ATF-2 regulated sterol carrier protein-2 promoter activities in the larval midgut of the yellow fever mosquito, Aedes aegypti

Expression of sterol carrier protein-2 (SCP-2) in Aedes aegypti shows a distinct temporal/spatial pattern throughout the life cycle. In order to identify the transcription factors responsible for the larval temporal/spatial regulation of AeSCP-2 transcription, AeSCP-2 promoter activities were studied in vivo via transient transfection of promoter/reporter gene assays. Regulatory sequences upstream −1.3 kb of the transcription start site of AeSCP-2 were found to be critical for the in vivo temporal/spatial promoter activity. Interestingly, the −1.6 kb promoter sequence efficiently drove the larval midgut-specific siRNA expression, indicating that the −1.6 kb upstream sequence is sufficient for temporal/spatial AeSCP-2 transcriptional activity. Four transcription factors were identified in the midgut nuclear extract from feeding larvae via labeled −1.6/−1.3 kb DNA probe pull-down and proteomic analysis. Co-transfection of the promoter/reporter gene with inducible siRNA expression of each transcription factor was performed to confirm the regulatory function of individual transcription factor on AeSCP-2 transcriptional activities in the larval midgut. The results indicate that two of the identified transcription factors, Thanatos-associated protein (THAP) and activating transcription factor-2 (ATF-2), antagonistically control AeSCP-2 transcriptional activity in the midgut of feeding larvae via the regulatory sequences between −1.6 to −1.3 kb 5′ upstream of the transcription start site. In vivo expression knockdown of THAP and ATF-2 resulted in significant changes in developmental progression, which may be partially due to their effects on AeSCP-2 expression.

Towards the classification of DYT6 dystonia mutants in the DNA-binding domain of THAP1

The transcription factor THAP1 (THanatos Associated Protein 1) has emerged recently as the cause of DYT6 primary dystonia, a type of rare, familial and mostly early-onset syndrome that leads to involuntary muscle contractions. Many of the mutations described in the DYT6 patients fall within the sequence-specific DNA-binding domain (THAP domain) of THAP1 and are believed to negatively affect DNA binding. Here, we have used an integrated approach combining spectroscopic (NMR, fluorescence, DSF) and calorimetric (ITC) methods to evaluate the effect of missense mutations, within the THAP domain, on the structure, stability and DNA binding. Our study demonstrates that none of the mutations investigated failed to bind DNA and some of them even bind DNA stronger than the wild-type protein. However, some mutations could alter DNA-binding specificity. Furthermore, the most striking effect is the decrease of stability observed for mutations at positions affecting the zinc coordination, the hydrophobic core or the C-terminal AVPTIF motif, with unfolding temperatures ranging from 46°C for the wild-type to below 37°C for two mutations. These findings suggest that reduction in population of folded protein under physiological conditions could also account for the disease.

Mutations in CIZ1 cause adult onset primary cervical dystonia

OBJECTIVE

Primary dystonia is usually of adult onset, can be familial, and frequently involves the cervical musculature. Our goal was to identify the causal mutation in a family with adult onset, primary cervical dystonia.

METHODS

Linkage and haplotype analyses were combined with solution-based whole-exome capture and massively parallel sequencing in a large Caucasian pedigree with adult onset, primary cervical dystonia to identify a cosegregating mutation. High-throughput screening and Sanger sequencing were completed in 308 Caucasians with familial or sporadic adult onset cervical dystonia and matching controls for sequence variants in this mutant gene.

RESULTS

Exome sequencing led to the identification of an exonic splicing enhancer mutation in exon 7 of CIZ1 (c.790A>G, p.S264G), which encodes CIZ1, Cip1-interacting zinc finger protein 1. CIZ1 is a p21(Cip1/Waf1) -interacting zinc finger protein expressed in brain and involved in DNA synthesis and cell-cycle control. Using a minigene assay, we showed that c.790A>G altered CIZ1 splicing patterns. The p.S264G mutation also altered the nuclear localization of CIZ1. Screening in subjects with adult-onset cervical dystonia identified 2 additional CIZ1 missense mutations (p.P47S and p.R672M).

INTERPRETATION

Mutations in CIZ1 may cause adult onset, primary cervical dystonia, possibly by precipitating neurodevelopmental abnormalities that manifest in adults and/or G1/S cell-cycle dysregulation in the mature central nervous system.

Genotype-phenotype correlations in THAP1 dystonia: molecular foundations and description of new cases

An extensive variety of THAP1 sequence variants have been associated with focal, segmental and generalized dystonia with age of onset ranging from 3 to over 60 years. In previous work, we screened 1114 subjects with mainly adult-onset primary dystonia (Neurology 2010; 74:229-238) and identified 6 missense mutations in THAP1. For this report, we screened 750 additional subjects for mutations in coding regions of THAP1 and interrogated all published descriptions of THAP1 phenotypes (gender, age of onset, anatomical distribution of dystonia, family history and site of onset) to explore the possibility of THAP1 genotype-phenotype correlations and facilitate a deeper understanding of THAP1 pathobiology. We identified 5 additional missense mutations in THAP1 (p.A7D, p.K16E, p.S21C, p.R29Q, and p.I80V). Three of these variants are associated with appendicular tremors, which were an isolated or presenting sign in some of the affected subjects. Abductor laryngeal dystonia and mild blepharospasm can be manifestations of THAP1 mutations in some individuals. Overall, mean age of onset for THAP1 dystonia is 16.8 years and the most common sites of onset are the arm and neck, and the most frequently affected anatomical site is the neck. In addition, over half of patients exhibit either cranial or laryngeal involvement. Protein truncating mutations and missense mutations within the THAP domain of THAP1 tend to manifest at an earlier age and exhibit more extensive anatomical distributions than mutations localized to other regions of THAP1.

A transcriptional regulatory role of the THAP11-HCF-1 complex in colon cancer cell function

The recently identified Thanatos-associated protein (THAP) domain is an atypical zinc finger motif with sequence-specific DNA-binding activity. Emerging data suggest that THAP proteins may function in chromatin-dependent processes, including transcriptional regulation, but the roles of most THAP proteins in normal and aberrant cellular processes remain largely unknown. In this work, we identify THAP11 as a transcriptional regulator differentially expressed in human colon cancer. Immunohistochemical analysis of human colon cancers revealed increased THAP11 expression in both primary tumors and metastases. Knockdown of THAP11 in SW620 colon cancer cells resulted in a significant decrease in cell proliferation, and profiling of gene expression in these cells identified a novel gene set composed of 80 differentially expressed genes, 70% of which were derepressed by THAP11 knockdown. THAP11 was found to associate physically with the transcriptional coregulator HCF-1 (host cell factor 1) and recruit HCF-1 to target promoters. Importantly, THAP11-mediated gene regulation and its chromatin association require HCF-1, while HCF-1 recruitment at these genes requires THAP11. Collectively, these data provide the first characterization of THAP11-dependent gene expression in human colon cancer cells and suggest that the THAP11-HCF-1 complex may be an important transcriptional and cell growth regulator in human colon cancer.

Structural basis for sequence-specific DNA recognition by an Arabidopsis WRKY transcription factor

The WRKY family transcription factors regulate plant-specific reactions that are mostly related to biotic and abiotic stresses. They share the WRKY domain, which recognizes a DNA element (TTGAC(C/T)) termed the W-box, in target genes. Here, we determined the solution structure of the C-terminal WRKY domain of Arabidopsis WRKY4 in complex with the W-box DNA by NMR. A four-stranded β-sheet enters the major groove of DNA in an atypical mode termed the β-wedge, where the sheet is nearly perpendicular to the DNA helical axis. Residues in the conserved WRKYGQK motif contact DNA bases mainly through extensive apolar contacts with thymine methyl groups. The importance of these contacts was verified by substituting the relevant T bases with U and by surface plasmon resonance analyses of DNA binding.

Milestones in dystonia

The last 25 years have seen remarkable advances in our understanding of the genetic etiologies of dystonia, new approaches into dissecting underlying pathophysiology, and independent progress in identifying effective treatments. In this review we highlight some of these advances, especially the genetic findings that have taken us from phenomenological to molecular-based diagnoses. Twenty DYT loci have been designated and 10 genes identified, all based on linkage analyses in families. Hand in hand with these genetic findings, neurophysiological and imaging techniques have been employed that have helped illuminate the similarities and differences among the various etiological dystonia subtypes. This knowledge is just beginning to yield new approaches to treatment including those based on DYT1 animal models. Despite the lag in identifying genetically based therapies, effective treatments, including impressive benefits from deep brain stimulation and botulinum toxin chemodenervation, have marked the last 25 years. The challenge ahead includes continued advancement into understanding dystonia's many underlying causes and associated pathology and using this knowledge to advance treatment including preventing genetic disease expression.

Identification and functional analysis of novel THAP1 mutations

Mutations in THAP1 have been associated with dystonia 6 (DYT6). THAP1 encodes a transcription factor that represses the expression of DYT1. To further evaluate the mutational spectrum of THAP1 and its associated phenotype, we sequenced THAP1 in 567 patients with focal (n = 461), segmental (n = 68), or generalized dystonia (n = 38). We identified 10 novel variants, including six missense substitutions within the DNA-binding Thanatos-associated protein domain (Arg13His, Lys16Glu, His23Pro, Lys24Glu, Pro26Leu, Ile80Val), a 1bp-deletion downstream of the nuclear localization signal (Asp191Thrfs*9), and three alterations in the untranslated regions. The effect of the missense variants was assessed using prediction tools and luciferase reporter gene assays. This indicated the Ile80Val substitution as a benign variant. The subcellular localization of Asp191Thrfs*9 suggests a disturbed nuclear import for this mutation. Thus, we consider six of the 10 novel variants as pathogenic mutations accounting for a mutation frequency of 1.1%. Mutation carriers presented mainly with early onset dystonia (<12 years in five of six patients). Symptoms started in an arm or neck and spread to become generalized in three patients or segmental in two patients. Speech was affected in four mutation carriers. In conclusion, THAP1 mutations are rare in unselected dystonia patients and functional analysis is necessary to distinguish between benign variants and pathogenic mutations.

Dimerization of the DYT6 dystonia protein, THAP1, requires residues within the coiled-coil domain

Thanatos-associated [THAP] domain-containing apoptosis-associated protein 1 (THAP1) is a DNA-binding protein that has been recently associated with DYT6 dystonia, a hereditary movement disorder involving sustained, involuntary muscle contractions. A large number of dystonia-related mutations have been identified in THAP1 in diverse patient populations worldwide. Previous reports have suggested that THAP1 oligomerizes with itself via a C-terminal coiled-coil domain, raising the possibility that DYT6 mutations in this region might affect this interaction. In this study, we examined the ability of wild-type THAP1 to bind itself and the effects on this interaction of the following disease mutations: C54Y, F81L, ΔF132, T142A, I149T, Q154fs180X, and A166T. The results confirmed that wild-type THAP1 associated with itself and most of the DYT6 mutants tested, except for the Q154fs180X variant, which loses most of the coiled-coil domain because of a frameshift at position 154. However, deletion of C-terminal residues after position 166 produced a truncated variant of THAP1 that was able to bind the wild-type protein. The interaction of THAP1 with itself therefore required residues within a 13-amino acid region (aa 154-166) of the coiled-coil domain. Further inspection of this sequence revealed elements highly consistent with previous descriptions of leucine zippers, which serve as dimerization domains in other transcription factor families. Based on this similarity, a structural model was generated to predict how hydrophobic residues in this region may mediate dimerization. These observations offer additional insight into the role of the coiled-coil domain in THAP1, which may facilitate future analyses of DYT6 mutations in this region.

Functional diversification of the RING finger and other binuclear treble clef domains in prokaryotes and the early evolution of the ubiquitin system

Recent studies point to a diverse assemblage of prokaryotic cognates of the eukaryotic ubiquitin (Ub) system. These systems span an entire spectrum, ranging from those catalyzing cofactor and amino acid biosynthesis, with only adenylating E1-like enzymes and ubiquitin-like proteins (Ubls), to those that are closer to eukaryotic systems by virtue of possessing E2 enzymes. Until recently E3 enzymes were unknown in such prokaryotic systems. Using contextual information from comparative genomics, we uncover a diverse group of RING finger E3s in prokaryotes that are likely to function with E1s, E2s, JAB domain peptidases and Ubls. These E1s, E2s and RING fingers suggest that features hitherto believed to be unique to eukaryotic versions of these proteins emerged progressively in such prokaryotic systems. These include the specific configuration of residues associated with oxyanion-hole formation in E2s and the C-terminal UFD in the E1 enzyme, which presents the E2 to its active site. Our study suggests for the first time that YukD-like Ubls might be conjugated by some of these systems in a manner similar to eukaryotic Ubls. We also show that prokaryotic RING fingers possess considerable functional diversity and that not all of them are involved in Ub-related functions. In eukaryotes, other than RING fingers, a number of distinct binuclear (chelating two Zn atoms) and mononuclear (chelating one zinc atom) treble clef domains are involved in Ub-related functions. Through detailed structural analysis we delineated the higher order relationships and interaction modes of binuclear treble clef domains. This indicated that the FYVE domain acquired the binuclear state independently of the other binuclear forms and that different treble clef domains have convergently acquired Ub-related functions independently of the RING finger. Among these, we uncover evidence for notable prokaryotic radiations of the ZF-UBP, B-box, AN1 and LIM clades of treble clef domains and present contextual evidence to support their role in functions unrelated to the Ub-system in prokaryotes. In particular, we show that bacterial ZF-UBP domains are part of a novel cyclic nucleotide-dependent redox signaling system, whereas prokaryotic B-box, AN1 and LIM domains have related functions as partners of diverse membrane-associated peptidases in processing proteins. This information, in conjunction with structural analysis, suggests that these treble clef domains might have been independently recruited to the eukaryotic Ub-system due to an ancient conserved mode of interaction with peptides.

Hybrid approach to analysis of β-sheet structures based on signal processing and statistical consideration

A number of biotechnology applications are based on protein design. For this design, the relationship between a protein’s primary structure and its conformation is of vital importance. A β-sheet is a common feature of a protein’s two-dimensional structure; therefore, elucidating the principles governing β-sheet structure and its stability is critical for understanding the protein-folding process. In the three-dimensional representation of protein molecules, C α carbon coordinates (carbon atom immediately adjacent to the carboxylate group) have often been employed instead of the complete set of coordinates for the corresponding residues. Using the C α carbon coordinates, we showed that particular amino acids are not randomly distributed within a β-sheet structure. On the basis of a new statistical approach for the analysis of a spatial distribution of amino acids in a protein, presented by their physico-chemical parameters, the electron–ion interaction potential (EIIP) and hydrophobicity, are described here. The relationship between amino acid positions inside the β-sheet and the EIIP and hydrophobicity parameters was established. The correlation between amino acid propensities related to the β-sheet was examined using multiple cross-spectra analysis. We also applied the continuous wavelet transform for the analysis of selected β-sheet structures using the EIIP and hydrophobicity parameters. The findings provide new insight into conformational propensities of amino acids for the adaption of β-sheet structures.

Nuclear magnetic resonance analysis of protein-DNA interactions

Recent methodological and instrumental advances in solution-state nuclear magnetic resonance have opened up the way to investigating challenging problems in structural biology such as large macromolecular complexes. This review focuses on the experimental strategies currently employed to solve structures of protein-DNA complexes and to analyse their dynamics. It highlights how these approaches can help in understanding detailed molecular mechanisms of target recognition.

Genetic and clinical features of primary torsion dystonia

Primary torsion dystonia (PTD) is defined as a syndrome in which dystonia is the only clinical sign (except for tremor), and there is no evidence of neuronal degeneration or an acquired cause by history or routine laboratory assessment. Seven different loci have been recognized for PTD but only two of the genes have been identified. In this review we will describe the phenotypes associated with these loci and discuss the responsible gene. This article is part of a Special Issue entitled "Advances in dystonia".

Molecular pathways in dystonia

The hereditary dystonias comprise a set of diseases defined by a common constellation of motor deficits. These disorders are most likely associated with different molecular etiologies, many of which have yet to be elucidated. Here we discuss recent advances in three forms of hereditary dystonia, DYT1, DYT6 and DYT16, which share a similar clinical picture: onset in childhood or adolescence, progressive spread of symptoms with generalized involvement of body regions and a steady state affliction without treatment. Unlike DYT1, the genes responsible for DYT6 and DYT16 have only recently been identified, with relatively little information about the function of the encoded proteins. Nevertheless, recent data suggest that these proteins may fit together within interacting pathways involved in dopaminergic signaling, transcriptional regulation, and cellular stress responses. This review focuses on these molecular pathways, highlighting potential common themes among these dystonias which may serve as areas for future research. This article is part of a Special Issue entitled "Advances in dystonia".