Forkhead Box P2 Research Articles

Analysis of two language-related genes in autism

Impairment of language abilities is a common feature in autistic individuals. Heterozygous mutations in the Forkhead Box P2 (FOXP2) gene lead to a severe spoken language disorder. Recently, several studies have pinpointed the involvement of common variants of the Contactin-Associated Protein-Like 2 (CNTNAP2) gene, whose transcription is regulated by the product of FOXP2, in several disorders characterized by language impairments such as autism, specific language impairment (SLI), and selective mutism (SM). In the present study, common variants of the FOXP2 and the CNTNAP2 genes were analyzed through a case-control association study in 322 Spanish autistic patients and 524 controls. The results of this study suggest that common variants of FOXP2 are unlikely to contribute to autism susceptibility, in agreement with previous findings. Furthermore, we failed to replicate in our sample a previous association finding of two single nucleotide polymorphisms (rs2710102 and rs7794745) in the CNTNAP2 gene with autism. No evidence for the association of these genes with language traits was observed in our analysis.

First Knockdown Gene Expression in Bat (Hipposideros armiger) Brain Mediated by Lentivirus

Lentivirus-mediated RNA interference (RNAi) is a potent experimental tool for investigating gene functions in vitro and in vivo. It has advantages that transgenic technology lacks. However, in vivo applications are difficult to apply in the central nervous system of non-model organisms due to the lack of a standard brain atlas and genetic information. Here, we report the development of an in vivo gene delivery system used in bat brain tissue for the first time, based on lentivirus (LV) vectors expressing short hairpin RNA (shRNA) targeting Hipposideros armiger forkhead box P2 (FoxP2). In vitro transfection into HEK 293T cell with the vector bearing the cassettes encoding FoxP2 shRNA verified the knockdown efficiency. Pseudovirus particles were administered via stereotactic intracerebral microinjection into the anterior cingulate cortex of H. armiger. FoxP2 is of major interest because of its role in sensorimotor coordination and probably in echolocation. Subsequent in situ hybridization validated the in vivo silencing of the target gene. This report demonstrates that LV-mediated expression of RNAi could achieve effective gene silencing in bats, a non-model organism, and will assist in elucidating the functions of bat genes.

An association study of sequence variants in the forkhead box P2 (FOXP2) gene and adulthood attention-deficit/hyperactivity disorder in two European samples

Attention-deficit/hyperactivity disorder (ADHD) is a common psychiatric disorder manifesting as symptoms of inattention, hyperactivity, and/or impulsivity. Learning disabilities co-occur with ADHD in 20-30% of cases and this high co-occurrence raises the possibility of a common etiological background. Forkhead box P2 (FOXP2) encodes a transcription factor involved in speech and language impairment and in the control of the corticobasal ganglia circuits known to be relevant in ADHD, suggesting a possible role of FOXP2 in ADHD. Our aim was to carry out an association study between FOXP2 and adulthood ADHD. We carried out a case-control association study in 643 adult ADHD patients and 619 controls from Germany and in 361 adult ADHD patients and 442 controls from Spain with 12 tagging single nucleotide polymorphisms covering the FOXP2 gene. The single-marker and multiple-marker analyses showed an association between FOXP2 and combined ADHD in the German cohort [rs12533005: P=0.0033; odds ratio=1.30 (1.09-1.56); rs12533005/rs1229761: P=4.1e-04; odds ratio=1.38 (1.15-1.66)]. These positive results, however, were not confirmed in the Spanish sample. Although these preliminary findings provide a tentative evidence for the contribution of FOXP2 to ADHD and suggest common genetic factors for this psychiatric disorder and learning disabilities, they should be interpreted with caution. Further studies in larger samples are needed to clarify the role of this transcription factor in ADHD.

The DISC1 promoter: characterization and regulation by FOXP2

Disrupted in schizophrenia 1 (DISC1) is a leading candidate susceptibility gene for schizophrenia, bipolar disorder and recurrent major depression, which has been implicated in other psychiatric illnesses of neurodevelopmental origin, including autism. DISC1 was initially identified at the breakpoint of a balanced chromosomal translocation, t(1;11) (q42.1;14.3), in a family with a high incidence of psychiatric illness. Carriers of the translocation show a 50% reduction in DISC1 protein levels, suggesting altered DISC1 expression as a pathogenic mechanism in psychiatric illness. Altered DISC1 expression in the post-mortem brains of individuals with psychiatric illness and the frequent implication of non-coding regions of the gene by association analysis further support this assertion. Here, we provide the first characterization of the DISC1 promoter region. Using dual luciferase assays, we demonstrate that a region -300 to -177 bp relative to the transcription start site (TSS) contributes positively to DISC1 promoter activity, while a region -982 to -301 bp relative to the TSS confers a repressive effect. We further demonstrate inhibition of DISC1 promoter activity and protein expression by forkhead-box P2 (FOXP2), a transcription factor implicated in speech and language function. This inhibition is diminished by two distinct FOXP2 point mutations, R553H and R328X, which were previously found in families affected by developmental verbal dyspraxia. Our work identifies an intriguing mechanistic link between neurodevelopmental disorders that have traditionally been viewed as diagnostically distinct but which do share varying degrees of phenotypic overlap.

FOXP2, APOE, and PRNP: New Modulators in Primary Progressive Aphasia

Primary progressive aphasia (PPA) is a heterogeneous disorder characterized by progressive language impairment. Polymorphisms within forkhead box P2 gene (FOXP2) gene have been associated with speech and language impairment. Apolipoprotein E (APOE) genotype and PRNP 129 codon status have been demonstrated to increase the risk of PPA, but with contrasting results. In the present study, we have evaluated the impact of FOXP2, APOE and PRNP genetic variations as risk factors and/or disease-modulators in PPA. 94 PPA patients and 200 age-matched healthy controls were considered and FOXP2 polymorphisms (rs1456031, rs17137124), APOE genotype, and PRNP codon 129 polymorphism analyzed. In 34 PPA patients, SPECT imaging data were analyzed by Statistical Parametric Mapping (SPM8). Genetic distributions and allele frequencies of FOXP2 and PRNP polymorphisms did not differ between groups while APOE ε4 was more represented in PPA as compared to controls. PPA patients carrying at-risk FOXP2 polymorphisms (rs1456031 and/or rs17137124) showed greater hypoperfusion in the frontal areas, namely the left inferior frontal gyrus and the right cingulated gyrus compared to non-carriers (p < 0.005). PPA patients carrying at least one ε4 allele had greater hypoperfusion in orbitofrontal regions (superior frontal gyrus and orbital gyrus) as compared to non-carriers ε4 (p < 0.005). PRNP codon 129 homozigosity correlated with left frontotemporal hypoperfusion (p < 0.005). Genetic variations within FOXP2, APOE, and PRNP modulate PPA disease, leading to a specific regional hypoperfusion according to different molecular pathways. APOE ε4 is overrepresented in PPA, thus likely acting as genetic risk factor on disease development.

Characterization of the immunological microenvironment of tumour buds and its impact on prognosis in mismatch repair-proficient and -deficient colorectal cancers

Tumour budding in colorectal cancer is established as a poor prognostic factor. The inverse correlation of tumour buds with peritumoural lymphocytic inflammation suggests an interaction with specific immune responses. The aims of this study were to characterize the immunological microenvironment of tumour buds and its impact on prognosis in mismatch repair (MMR)-proficient and -deficient colorectal cancers. A total of 297 colorectal cancers were double-immunostained for CK22 plus one of the following: CD138, CD16, CD20, CD21, CD56, CD68, CD8, forkhead box P2 (FoxP3), granzyme B, mast cell tryptase, CD3 or T cell intracellular antigen-1 (TIA)-1. Tumour buds and immune cells within the region of densest budding were evaluated [×40 high-power field (HPF)] simultaneously. In both MMR-proficient and -deficient cancers, CD8(+), FoxP3(+) and CD68(+) cells were observed most frequently (>40 cells/HPF) and were independent prognostic factors. A combined prognostic score of tumour budding and CD8(+), FoxP3(+) and CD68(+) distinctly identified patients with low-, moderate- or high-risk colorectal cancers with 5-year survival rates of 75.2% [confidence interval 95% (CI): 66-83], 56.3% (95% CI: 43-68) and 25.2% (95% CI: 14-38), respectively, in MMR-proficient and -deficient cancers. The combined assessment of tumour budding with CD8, FoxP3 and CD68 lymphocytes could represent a basis for a prognostic score similar to the Bloom Richardson grade (BRE) and Gleason scores for breast and prostatic cancers.

Twitter evolution: converging mechanisms in birdsong and human speech

Vocal imitation in human infants and in some orders of birds relies on auditory-guided motor learning during a sensitive period of development. It proceeds from 'babbling' (in humans) and 'subsong' (in birds) through distinct phases towards the full-fledged communication system. Language development and birdsong learning have parallels at the behavioural, neural and genetic levels. Different orders of birds have evolved networks of brain regions for song learning and production that have a surprisingly similar gross anatomy, with analogies to human cortical regions and basal ganglia. Comparisons between different songbird species and humans point towards both general and species-specific principles of vocal learning and have identified common neural and molecular substrates, including the forkhead box P2 (FOXP2) gene.

Involvement of T helper type 17 and regulatory T cell activity in tumour immunology of bladder carcinoma

T helper type 17 (Th17) and regulatory T cells (T(reg) ) play an important role in the pathogenesis of inflammation and autoimmune disorders. Recent studies have suggested that they also had an impact on tumour immunology. However, the relationship between Th17 and T(reg) cells in the pathogenesis of bladder carcinoma is still unclear. Flow cytometry was used to analyse the numbers, phenotype and cytokine production of Th17 cells in peripheral blood and tumour tissue from bladder carcinoma patients, in parallel with analysis of T(reg) cells. The suppressor capacity of T(reg) and the potential effects of interleukin (IL)-2 on the differentiation of Th17 and T(reg) cells in vitro were studied in a T cell stimulation and suppression assays. The results were as follows: Th17 cells were enriched in the tumours of patients with bladder carcinoma compared with the peripheral blood of patients and controls; patients with bladder carcinoma had a higher proportion of T(reg) cells in peripheral blood compared with healthy controls and nearly all patients examined showed a relative enrichment of tumour-infiltrating T(reg) with respect to peripheral blood; there appeared to be an inverse relationship between tumour-infiltrating Th17 and T(reg) cells; IL-2 could convert tumour-infiltrating T(reg) cells cultured in the presence of the autologous irradiated CD3(-) fraction into Th17 cells, down-regulate forkhead box P2 expression and suppressive capacity of T(reg) cells. This study is the first to define the frequency and characteristics of Th17 cells in bladder carcinoma. We suggest that the balance between Th17 and T(reg) cells may be involved in the development or progression of bladder carcinoma.

Recent advances in the genetics of language impairment

Specific language impairment (SLI) is defined as an unexpected and persistent impairment in language ability despite adequate opportunity and intelligence and in the absence of any explanatory medical conditions. This condition is highly heritable and affects between 5% and 8% of pre-school children. Over the past few years, investigations have begun to uncover genetic factors that may contribute to susceptibility to language impairment. So far, variants in four specific genes have been associated with spoken language disorders - forkhead box P2 (FOXP2) and contactin-associated protein-like 2 (CNTNAP2) on chromosome7 and calcium-transporting ATPase 2C2 (ATP2C2) and c-MAF inducing protein (CMIP) on chromosome 16. Here, we describe the different ways in which these genes were identified as candidates for language impairment. We discuss how characterization of these genes, and the pathways in which they are involved, may enhance our understanding of language disorders and improve our understanding of the biological foundations of language acquisition.

The enigma of speech and language acquisition in human - A genetic approach

The use of language is one of the most vital traits that distinguish human from other species. The gene FOXP2 (fork head box P2) is relevant to the human ability to develop language. FOXP2 is situated on human chromosome 7q31, and its major splice form encodes a protein of 715 amino acids. It contains a glutamine rich region consisting of two adjacent polyglutamine tracts, encoded by mixtures of CAG and CAA repeats. Two functional copy of FOXP2 seem to be required for acquisition of normal language in human. The chimpanzee, gorilla and the rhesus macaque FOXP2 proteins are all identical to each other and carry only one difference from the mouse and two differences from the human protein, whereas the orangutan two differences from the mouse and three from humans. This gene is also important on particular aspects of cognition awareness or grammatical processing.

Human-specific transcriptional regulation of CNS development genes by FOXP2

The signaling pathways orchestrating both the evolution and development of language in the human brain remain unknown. To date, the transcription factor FOXP2 (forkhead box P2) is the only gene implicated in Mendelian forms of human speech and language dysfunction1,2,3. It has been proposed, that the amino acid composition in the human variant of FOXP2 has undergone accelerated evolution, and this change occurred around the time of language emergence in humans4,5. However, this remains controversial, and whether the acquisition of these amino acids in human FOXP2 has any functional consequence in human neurons remains untested. Here, we demonstrate that these two amino acids alter FOXP2 function by conferring differential transcriptional regulation in vitro. We extend these observations in vivo to human and chimpanzee brain, and use network analysis to identify novel relationships among the differentially expressed genes. These data provide experimental support for the functional relevance of changes in FOXP2 that occur on the human lineage, highlighting specific pathways with direct consequences for human brain development and disease. Since FOXP2 has an important role in speech and language in humans, the identified targets may have a critical function in the development and evolution of language circuitry in humans.

Simple and Sensitive Method for Identification of Human DNA by Allele‐Specific Polymerase Chain Reaction of FOXP2

The forkhead box P2 (FOXP2) gene is specifically involved in speech and language development in humans. The sequence is well conserved among many vertebrate species but has accumulated amino acid changes in the human lineage. The aim of this study was to develop a simple method to discriminate between human and nonhuman vertebrate DNA in forensic specimens by amplification of a human-specific genomic region. In the present study, we designed an allele-specific polymerase chain reaction (PCR) using primers to amplify smaller than 70-bp regions of FOXP2 to identify DNA as being of human or nonhuman, including ape, origin. PCR amplification was also successfully performed using fluorescence-labeled primers, and this method allows a single PCR reaction with a genomic DNA sample as small as 0.01 ng. This system also identified the presence of human DNA in two blood stains stored for 20 and 38 years. The results suggested the potential usefulness of FOXP2 as an identifier of human DNA in forensic samples.

Genetics of Specific Language Impairment

Specific language impairment is a disorder that occurs in up to 7% of children aged 5 to 6 years. Typical specific language impairment involves both comprehension and production deficits and is associated with deficits in repeating nonsense words. Although no gene has been implicated in most cases of this disorder, mutations in the gene for the forkhead box P2 (FOXP2) transcription factor are associated with a rare autosomal dominant form that affects approximately 2% of all …

Ultrasonic vocalization impairment of Foxp2 (R552H) knockin mice related to speech-language disorder and abnormality of Purkinje cells

Previous studies have demonstrated that mutation in the forkhead domain of the forkhead box P2 (FOXP2) protein (R553H) causes speech-language disorders. To further analyze FOXP2 function in speech learning, we generated a knockin (KI) mouse for Foxp2 (R552H) [Foxp2 (R552H)-KI], corresponding to the human FOXP2 (R553H) mutation, by homologous recombination. Homozygous Foxp2 (R552H)-KI mice showed reduced weight, immature development of the cerebellum with incompletely folded folia, Purkinje cells with poor dendritic arbors and less synaptophysin immunoreactivity, and achieved crisis stage for survival 3 weeks after birth. At postnatal day 10, these mice also showed severe ultrasonic vocalization (USV) and motor impairment, whereas the heterozygous Foxp2 (R552H)-KI mice exhibited modest impairments. Similar to the wild-type protein, Foxp2 (R552H) localized in the nuclei of the Purkinje cells and the thalamus, striatum, cortex, and hippocampus (CA1) neurons of the homozygous Foxp2 (R552H)-KI mice (postnatal day 10), and some of the neurons showed nuclear aggregates of Foxp2 (R552H). In addition to the immature development of the cerebellum, Foxp2 (R552H) nuclear aggregates may further compromise the function of the Purkinje cells and cerebral neurons of the homozygous mice, resulting in their death. In contrast, heterozygous Foxp2 (R552H)-KI mice, which showed modest impairment of USVs with different USV qualities and which did not exhibit nuclear aggregates, should provide insights into the common molecular mechanisms between the mouse USV and human speech learning and the relationship between the USV and motor neural systems.

Intracellular distribution of a speech/language disorder associated FOXP2 mutant

Although a mutation (R553H) in the forkhead box (FOX)P2 gene is associated with speech/language disorder, little is known about the function of FOXP2 or its relevance to this disorder. In the present study, we identify the forkhead nuclear localization domains that contribute to the cellular distribution of FOXP2. Nuclear localization of FOXP2 depended on two distally separated nuclear localization signals in the forkhead domain. A truncated version of FOXP2 lacking the leu-zip, Zn 2+ finger, and forkhead domains that was observed in another patient with speech abnormalities demonstrated an aggregated cytoplasmic localization. Furthermore, FOXP2 (R553H) mainly exhibited a cytoplasmic localization despite retaining interactions with nuclear transport proteins (importin α and β). Interestingly, wild type FOXP2 promoted the transport of FOXP2 (R553H) into the nucleus. Mutant and wild type FOXP2 heterodimers in the nucleus or FOXP2 R553H in the cytoplasm may underlie the pathogenesis of the autosomal dominant speech/language disorder.

Absence of a Paternally Inherited FOXP2 Gene in Developmental Verbal Dyspraxia

Mutations in FOXP2 cause developmental verbal dyspraxia (DVD), but only a few cases have been described. We characterize 13 patients with DVD--5 with hemizygous paternal deletions spanning the FOXP2 gene, 1 with a translocation interrupting FOXP2, and the remaining 7 with maternal uniparental disomy of chromosome 7 (UPD7), who were also given a diagnosis of Silver-Russell Syndrome (SRS). Of these individuals with DVD, all 12 for whom parental DNA was available showed absence of a paternal copy of FOXP2. Five other individuals with deletions of paternally inherited FOXP2 but with incomplete clinical information or phenotypes too complex to properly assess are also described. Four of the patients with DVD also meet criteria for autism spectrum disorder. Individuals with paternal UPD7 or with partial maternal UPD7 or deletion starting downstream of FOXP2 do not have DVD. Using quantitative real-time polymerase chain reaction, we show the maternally inherited FOXP2 to be comparatively underexpressed. Our results indicate that absence of paternal FOXP2 is the cause of DVD in patients with SRS with maternal UPD7. The data also point to a role for differential parent-of-origin expression of FOXP2 in human speech development.

Singing Mice, Songbirds, and More: Models for FOXP2 Function and Dysfunction in Human Speech and Language

In 2001, a point mutation in the forkhead box P2 (FOXP2) coding sequence was identified as the basis of an inherited speech and language disorder suffered by members of the family known as "KE." This mini-symposium review focuses on recent findings and research-in-progress, primarily from five laboratories. Each aims at capitalizing on the FOXP2 discovery to build a neurobiological bridge between molecule and phenotype. Below, we describe genetic through behavioral techniques used currently to investigate FoxP2 in birds, rodents, and humans for discovery of the neural bases of vocal learning and language.

FoxP2Regulation during Undirected Singing in Adult Songbirds

Learned vocal communication, including human speech, is a socially influenced behavior limited to certain animals. This ability requires auditory feedback during vocalization, which allows for on-line evaluation, to achieve the desired vocal output. To date, FOXP2 (forkhead box P2), a transcriptional repressor, is the only molecule directly linked to human speech. Identified FOXP2 mutations cause orofacial dyspraxia accompanied by abnormalities in corticostriatal circuitry controlling voluntary orofacial movements. These observations implicate FOXP2 in the developmental formation of neural circuits used in speech, but whether FOXP2 additionally plays an active role in mature circuitry was unknown. To address this question, we use a songbird, the zebra finch (Taeniopygia guttata), whose learned song and underlying circuitry are well characterized. We show that, when adult males sing, FoxP2 mRNA is acutely downregulated within area X, the specific region of the songbird striatum dedicated to song. Furthermore, we find downregulation in males that sing by themselves (undirected singers) but not in males that sing to females (directed singers). This FoxP2 downregulation cannot be a simple consequence of the motor act because birds sang in both directed and undirected contexts. Our data suggest that FoxP2 is important not only for the formation but also for the function of vocal control circuitry. Social context-dependent, acute changes in FoxP2 within the basal ganglia of adult songbirds also suggest, by analogy, that the core deficits of affected humans extend beyond development and beyond basic central motor control.

No association of FOXP2 and PTPRZ1 on 7q31 with autism from the Japanese population

Autism is a child-onset pervasive developmental disorder, with a significant role of genetic factors in its development. Genome-wide linkage studies have suggested a 7q region as a susceptibility locus for autism. We investigated several single nucleotide polymorphisms (SNPs) of Forkhead Box P2 ( FOXP2) and Protein-Tyrosine Phosphatase, Receptor-type, Zeta-1 ( PTPRZ1) at the 7q region in Japanese patients with autism and healthy controls. No significant difference was observed, after correction for the multiple testing, in allele, genotype or haplotype frequencies of the SNPs of FOXP2 or PTPRZ1 between patients and controls. No evidence was thus obtained for a major role of FOXP2 or PTPRZ1 in the development of autism.

Differentially expressed genes in mouse liver during development of fatty liver disease (FLD)

FLD is considered as the hepatic manifestation of the metabolic syndrome but still poorly understood at the molecular level. To study differentially expressed genes during development of FDL in C57BL/6 mice upon challenge with a high fat diet for 1 and 5 weeks, respectively. Hepatic gene expression was determined in livers from 3 groups of four male mice. Total liver RNA was isolated, reverse transcribed and labelled with Cy5- or Cy3-dUTP, respectively. Labeled probes were hybridized to the same microarray spotted with more than 17,000 oligonucleotides. Slides were scanned with a GENE PIX 4000B array scanner and signals of fluorescence-tagged cDNA spots were quantitated. Genes were considered to be expressed differentially if there was a greater than 1.5-fold difference in abundance of mRNA when compared with controls. Following one and five weeks on the high fat diet, liver weight increased by 22% (p<0.05) and 76% (p<0.005), respectively and liver specimens demonstrated an increasing number of fatty vacuoles with an inflammatory infiltrate after 5 weeks. Following 1 week of the high fat diet, 51 genes were differentially expressed (47 overexpressed) whereas at 5 weeks the number of differentially genes decreased to 19 (13 overexpressed). Highly overexpressed genes included Septin 2 (Sept2), Zinc finger protein 239 (Zfp239), Nerve growth factor beta (Ngfb), Ankyrin repeat domain 6 (Ankrd6), proprotein convertase subtilisin/kexin type 2 (Pcsk2), all of which are important for cell growth and differentiation. In addition activation of the immune response was noted by overexpression of small inducible cytokine A3 (Scya3), Interleukin 10 (IL10) and Linker of T-cell receptor pathways (Lnk). Interestingly, stearoyl-CoA desaturase 1 (Scd1), a rate-limiting enzyme in the synthetic pathway of unsaturated fatty acids was overexpressed, too. Genes with a significant down-regulation included Opsin (Opn3), Major urinary protein 3 (Mup3) and 4 (Mup4) both of which are members of the lipocalin family, Forkhead box P2 (Foxp2) and Cytidine 5'-triphosphate synthase (Ctps). In conclusion, our study provides a framework to identify genes with relevance for the development of FLD.