Role of the HCF-1 basic region in sustaining cell proliferation.

BACKGROUND: The human herpes simplex virus-associated host cell factor 1 (HCF-1) is a conserved human transcriptional co-regulator that links positive and negative histone modifying activities with sequence-specific DNA-binding transcription factors. It is synthesized as a 2035 amino acid precursor that is cleaved to generate an amino- (HCF-1(N)) terminal subunit, which promotes G1-to-S phase progression, and a carboxy- (HCF-1(C)) terminal subunit, which controls multiple aspects of cell division during M phase. The HCF-1(N) subunit contains a Kelch domain that tethers HCF-1 to sequence-specific DNA-binding transcription factors, and a poorly characterized so called "Basic" region (owing to a high ratio of basic vs. acidic amino acids) that is required for cell proliferation and has been shown to associate with the Sin3 histone deacetylase (HDAC) component. Here we studied the role of the Basic region in cell proliferation and G1-to-S phase transition assays. METHODOLOGY/PRINCIPAL FINDINGS: Surprisingly, much like the transcriptional activation domains of sequence-specific DNA-binding transcription factors, there is no unique sequence within the Basic region required for promoting cell proliferation or G1-to-S phase transition. Indeed, the ability to promote these activities is size dependent such that the shorter the Basic region segment the less activity observed. We find, however, that the Basic region requirements for promoting cell proliferation in a temperature-sensitive tsBN67 cell assay are more stringent than for G1-to-S phase progression in an HCF-1 siRNA-depletion HeLa-cell assay. Thus, either half of the Basic region alone can support G1-to-S phase progression but not cell proliferation effectively in these assays. Nevertheless, the Basic region displays considerable structural plasticity because each half is able to promote cell proliferation when duplicated in tandem. Consistent with a potential role in promoting cell-cycle progression, the Sin3a HDAC component can associate independently with either half of the Basic region fused to the HCF-1 Kelch domain. CONCLUSIONS/SIGNIFICANCE: While conserved, the HCF-1 Basic region displays striking structural flexibility for controlling cell proliferation.

Mutational analysis of BTAF1-TBP interaction: BTAF1 can rescue DNA-binding defective TBP mutants.

The BTAF1 transcription factor interacts with TATA-binding protein (TBP) to form the B-TFIID complex, which is involved in RNA polymerase II transcription. Here, we present an extensive mapping study of TBP residues involved in BTAF1 interaction. This shows that residues in the concave, DNA-binding surface of TBP are important for BTAF1 binding. In addition, BTAF1 interacts with residues in helix 2 on the convex side of TBP as assayed in protein-protein and in DNA-binding assays. BTAF1 drastically changes the TATA-box binding specificity of TBP, as it is able to recruit DNA-binding defective TBP mutants to both TATA-containing and TATA-less DNA. Interestingly, other helix 2 interacting factors, such as TFIIA and NC2, can also stabilize mutant TBP binding to DNA. In contrast, TFIIB which interacts with a distinct surface of TBP does not display this activity. Since many proteins contact helix 2 of TBP, this provides a molecular basis for mutually exclusive TBP interactions and stresses the importance of this structural element for eukaryotic transcription.

Update of the FANTOM web resource: from mammalian transcriptional landscape to its dynamic regulation.

The international Functional Annotation Of the Mammalian Genomes 4 (FANTOM4) research collaboration set out to better understand the transcriptional network that regulates macrophage differentiation and to uncover novel components of the transcriptome employing a series of high-throughput experiments. The primary and unique technique is cap analysis of gene expression (CAGE), sequencing mRNA 5'-ends with a second-generation sequencer to quantify promoter activities even in the absence of gene annotation. Additional genome-wide experiments complement the setup including short RNA sequencing, microarray gene expression profiling on large-scale perturbation experiments and ChIP-chip for epigenetic marks and transcription factors. All the experiments are performed in a differentiation time course of the THP-1 human leukemic cell line. Furthermore, we performed a large-scale mammalian two-hybrid (M2H) assay between transcription factors and monitored their expression profile across human and mouse tissues with qRT-PCR to address combinatorial effects of regulation by transcription factors. These interdependent data have been analyzed individually and in combination with each other and are published in related but distinct papers. We provide all data together with systematic annotation in an integrated view as resource for the scientific community (http://fantom.gsc.riken.jp/4/). Additionally, we assembled a rich set of derived analysis results including published predicted and validated regulatory interactions. Here we introduce the resource and its update after the initial release.

Control of hair follicle cell fate by underlying mesenchyme through a CSL-Wnt5a-FoxN1 regulatory axis.

Epithelial-mesenchymal interactions are key to skin morphogenesis and homeostasis. We report that maintenance of the hair follicle keratinocyte cell fate is defective in mice with mesenchymal deletion of the CSL/RBP-Jkappa gene, the effector of "canonical" Notch signaling. Hair follicle reconstitution assays demonstrate that this can be attributed to an intrinsic defect of dermal papilla cells. Similar consequences on hair follicle differentiation result from deletion of Wnt5a, a specific dermal papilla signature gene that we found to be under direct Notch/CSL control in these cells. Functional rescue experiments establish Wnt5a as an essential downstream mediator of Notch-CSL signaling, impinging on expression in the keratinocyte compartment of FoxN1, a gene with a key hair follicle regulatory function. Thus, Notch/CSL signaling plays a unique function in control of hair follicle differentiation by the underlying mesenchyme, with Wnt5a signaling and FoxN1 as mediators.

EWS-FLI1 Utilizes Divergent Chromatin Remodeling Mechanisms to Directly Activate or Repress Enhancer Elements in Ewing Sarcoma.

The aberrant transcription factor EWS-FLI1 drives Ewing sarcoma, but its molecular function is not completely understood. We find that EWS-FLI1 reprograms gene regulatory circuits in Ewing sarcoma by directly inducing or repressing enhancers. At GGAA repeat elements, which lack evolutionary conservation and regulatory potential in other cell types, EWS-FLI1 multimers induce chromatin opening and create de novo enhancers that physically interact with target promoters. Conversely, EWS-FLI1 inactivates conserved enhancers containing canonical ETS motifs by displacing wild-type ETS transcription factors. These divergent chromatin-remodeling patterns repress tumor suppressors and mesenchymal lineage regulators while activating oncogenes and potential therapeutic targets, such as the kinase VRK1. Our findings demonstrate how EWS-FLI1 establishes an oncogenic regulatory program governing both tumor survival and differentiation.

Analysis of a boundary protein delimiting chromatin domains in yeast

SUMMARY The expression state of a eukaryotic gene depends in part on its location in the chromosome. This position effect results from the organization of eukaryotic genomes into discrete functional domains, defined by local differences in chromatin structure. The expression of genes within each domain appears to be defined and maintained by the concerted action of regulatory elements such as promoters, enhancers, silencers and locus control regions. Individual domains may be bordered by boundary elements that separate regions of permissive and silent chromatin. When located next to chromosomal elements such as telomeres, genes can be subjected to epigenetic silencing. In yeast, this is mediated by the propagation of the SIR proteins from telomeres towards more centromeric regions. Particular transcription factors can protect downstream genes from silencing when tethered between the gene and the telomere, and they may thus act as chromatin domain boundaries. Here we have studied one of these transcription factors, CTF-1, that binds directly histone H3. A deletion mutagenesis localized the barrier activity to CTF-1 histone-binding domain. A saturating point mutagenesis of this domain identified several amino-acid substitutions that similarly inhibited the boundary and histone-binding activities. Chromatin immunoprecipitation experiments indicated that the barrier protein efficiently prevents the spreading of SIR proteins, and that it separates domains of hypoacetylated and hyperacetylated histones. Together, these results suggest a mechanism by which proteins such as CTF-1 may interact directly with histone H3 to prevent the propagation of a silent chromatin structure, thereby defining boundaries of permissive and silent chromatin domains. RESUME L'expression des gènes eucaryotes dépend en partie de leur localisation sur les chromosomes. Cet effet de position résulte de l'organisation des génomes eucaryotes en domaines fonctionnels, définis par des changements locaux au niveau de la structure de la chromatine. Dans chacun de ces domaines, l'expression des gènes est définie et maintenue par l'action concertée de différents éléments régulateurs tels que les promoteurs, les amplificateurs, les silenceurs et les locus control régions. Ces domaines peuvent être entourés par des éléments barrière, séparant les régions de chromatine répressive des régions permissive pour l'expression des gènes. Lorsqu'ils se situent à proximité d'éléments chromosomiques comme les telomères, les gènes peuvent être réprimés de manière épigénétique. Chez la levure, cette répression est établie par la propagation des protéines SIR depuis les télomères vers les régions centromériques. Certains facteurs de transcription peuvent empêcher la répression d'un gène, lorsqu'ils sont placés entre ce gène et le télomère. Nous avons étudié un de ces facteurs, CTF-1, qui a la particularité de lier directement l'histone H3. La délétion de certaines parties de CTF-1 a permis de déterminer que la région responsable de l'activité barrière correspond au domaine d'interaction avec H3. Plusieurs mutations points effectuées dans ce domaine inhibent à la fois l'activité barrière et la capacité de lier H3. Des expériences d'immuno-précipitation de la chromatine indiquent que la protéine barrière CTF-1 prévient efficacement la propagation des protéines SIR et sépare des domaines contenant des histones hypo-acétylées de ceux constitués d'histones hyper-acétylées. Ces résultats suggèrent que CTF-1 interagit directement avec l'histone H3 pour empêcher la propagation de la chromatine répressive, délimitant ainsi des domaines de chromatine permissive et des domaines de chromatine silencieuse.

The TT genotype of the STAT4 rs7574865 polymorphism is associated with high disease activity and disability in patients with early arthritis

BACKGROUND The number of copies of the HLA-DRB1 shared epitope, and the minor alleles of the STAT4 rs7574865 and the PTPN22 rs2476601 polymorphisms have all been linked with an increased risk of developing rheumatoid arthritis. In the present study, we investigated the effects of these genetic variants on disease activity and disability in patients with early arthritis. METHODOLOGY AND RESULTS We studied 640 patients with early arthritis (76% women; median age, 52 years), recording disease-related variables every 6 months during a 2-year follow-up. HLA-DRB1 alleles were determined by PCR-SSO, while rs7574865 and rs2476601 were genotyped with the Taqman 5' allelic discrimination assay. Multivariate analysis was performed using generalized estimating equations for repeated measures. After adjusting for confounding variables such as gender, age and ACPA, the TT genotype of rs7574865 in STAT4 was associated with increased disease activity (DAS28) as compared with the GG genotype (β coefficient [95% confidence interval] = 0.42 [0.01-0.83], p = 0.044). Conversely, the presence of the T allele of rs2476601 in PTPN22 was associated with diminished disease activity during follow-up in a dose-dependent manner (CT genotype = -0.27 [-0.56- -0.01], p = 0.042; TT genotype = -0.68 [-1.64- -0.27], p = 0.162). After adjustment for gender, age and disease activity, homozygosity for the T allele of rs7574865 in STAT4 was associated with greater disability as compared with the GG genotype. CONCLUSIONS Our data suggest that patients with early arthritis who are homozygous for the T allele of rs7574865 in STAT4 may develop a more severe form of the disease with increased disease activity and disability.

PIF3 is a repressor of chloroplast development.

The phytochrome-interacting factor PIF3 has been proposed to act as a positive regulator of chloroplast development. Here, we show that the pif3 mutant has a phenotype that is similar to the pif1 mutant, lacking the repressor of chloroplast development PIF1, and that a pif1pif3 double mutant has an additive phenotype in all respects. The pif mutants showed elevated protochlorophyllide levels in the dark, and etioplasts of pif mutants contained smaller prolamellar bodies and more prothylakoid membranes than corresponding wild-type seedlings, similar to previous reports of constitutive photomorphogenic mutants. Consistent with this observation, pif1, pif3, and pif1pif3 showed reduced hypocotyl elongation and increased cotyledon opening in the dark. Transfer of 4-d-old dark-grown seedlings to white light resulted in more chlorophyll synthesis in pif mutants over the first 2 h, and analysis of gene expression in dark-grown pif mutants indicated that key tetrapyrrole regulatory genes such as HEMA1 encoding the rate-limiting step in tetrapyrrole synthesis were already elevated 2 d after germination. Circadian regulation of HEMA1 in the dark also showed reduced amplitude and a shorter, variable period in the pif mutants, whereas expression of the core clock components TOC1, CCA1, and LHY was largely unaffected. Expression of both PIF1 and PIF3 was circadian regulated in dark-grown seedlings. PIF1 and PIF3 are proposed to be negative regulators that function to integrate light and circadian control in the regulation of chloroplast development.

Peroxisome proliferator-activated receptor-beta signaling contributes to enhanced proliferation of hepatic stellate cells.

BACKGROUND & AIMS: The peroxisome proliferator-activated nuclear receptors (PPAR-alpha, PPAR-beta, and PPAR-gamma), which modulate the expression of genes involved in energy homeostasis, cell cycle, and immune function, may play a role in hepatic stellate cell activation. Previous studies focused on the decreased expression of PPAR-gamma in hepatic stellate cell activation but did not investigate the expression and role of the PPAR-alpha and -beta isotypes. The aim of this study was to evaluate the expression of the different PPARs during hepatic stellate cell activation in vitro and in situ and to analyze possible factors that might contribute to their expression. In a second part of the study, the effect of a PPAR-beta agonist on acute liver injury was evaluated. METHODS: The effects of PPAR isotype-specific ligands on hepatic stellate cell transition were evaluated by bromodeoxyuridine incorporation, gel shifts, immunoprecipitation, and use of antisense PPAR-beta RNA-expressing adenoviruses. Tumor necrosis factor alpha-induced PPAR-beta phosphorylation and expression was evaluated by metabolic labeling and by using specific P38 inhibitors. RESULTS: Hepatic stellate cells constitutively express high levels of PPAR-beta, which become further induced during culture activation and in vivo fibrogenesis. No significant expression of PPAR-alpha or -gamma was found. Stimulation of the P38 mitogen-activated protein kinase pathway modulated the expression of PPAR-beta. Transcriptional activation of PPAR-beta by L165041 enhanced hepatic stellate cell proliferation. Treatment of rats with a single bolus of CCl(4) in combination with L165041 further enhanced the expression of fibrotic markers. CONCLUSIONS: PPAR-beta is an important signal-transducing factor contributing to hepatic stellate cell proliferation during acute and chronic liver inflammation.

Hes1 regulates corneal development and the function of corneal epithelial stem/progenitor cells.

Hes1, a major target gene in Notch signaling, regulates the fate and differentiation of various cell types in many developmental systems. To gain a novel insight into the role of Hes1 in corneal tissue, we performed gain-of-function and loss-of-function studies. We show that corneal development was severely disturbed in Hes1-null mice. Hes1-null corneas manifested abnormal junctional specialization, cell differentiation, and less cell proliferation ability. Worthy of note, Hes1 is expressed mainly in the corneal epithelial stem/progenitor cells and is not detected in the differentiated corneal epithelial cells. Expression of Hes1 is closely linked with corneal epithelial stem/progenitor cell proliferation activity in vivo. Moreover, forced Hes1 expression inhibits the differentiation of corneal epithelial stem/progenitor cells and maintains these cells' undifferentiated state. Our data provide the first evidence that Hes1 regulates corneal development and the homeostatic function of corneal epithelial stem/progenitor cells.

Remodelage des canaux potassiques dépendants de l'ATP lors de l'hypertrophie et de l'insuffisance cardiaque

RESUME :Introduction. Les maladies cardiovasculaires représentent la première cause de mortalité dans les pays développés et l'insuffisance cardiaque (IC) est la plus fréquente. Suite à un infarctus, le coeur des patients subit un remodelage ventriculaire pouvant évoluer vers un état d'IC. L'IC se définit comme un état dans lequel le coeur n'est plus capable d'approvisionner suffisamment les organes et cet état s'accompagne souvent de troubles du rythme cardiaque. Le remodelage ventriculaire touche de nombreux gènes codant à la fois pour les voies métaboliques et pour des canaux ioniques favorisant ainsi l'apparition des arythmies responsables de la mort subite des patients atteints d'IC. Comprendre ce passage entre remodelage et IC est crucial afin de pouvoir un jour prévenir l'IC et les complications médicales qui l'accompagnent. Nous nous sommes intéressés aux canaux potassiques dépendants de l'ATP (KATP) car ces canaux ont la capacité de coupler le métabolisme de la cellule à son activité électrique. En effet, les canaux KATP s'ouvrent quand la charge énergétique (rapport ATP/ ADP) de la cellule chute. Dans les cardiomyocytes, l'ouverture des KATP induit une hyperpolarisation de la membrane cellulaire ce qui diminue indirectement la surcharge calcique et de ce fait préserve la cellule. Les canaux KATp sont formés de 4 sous-unités Kir6.x (Kir6.1 ou Kir6.2) formant le pore du canal associées à 4 sous-unités régulatrices SUR. Les propriétés électrophysiologiques ainsi que la sensibilité pharmacologique des canaux KATP dépendent de leur composition et seuls les canaux KATP formés par la sous-unité Kirô.l sont activés par le diazoxyde.Méthodes et résultats. Nous avons d'abord montré dans un modèle in vivo d'IC chez le rat adulte que les sous-unités Kir6.1 et SUR sont surexprimées dans ces conditions pathologiques. Par ailleurs, les cardiomyocytes issus des coeurs infarcis deviennent sensibles au diazoxyde reflétant la surexpression de Kir6.1. Les potentiels d'action qui sont prolongés dans l'IC et qui sont à l'origine d'arythmies majeures sont normalisés par l'ouverture des canaux KATp induite par le diazoxyde. Ainsi, l'ouverture pharmacologique des canaux KATp contribuerait à la cardio-protection. Dans une seconde partie, nous avons déterminé quels étaient les facteurs de transcription responsables de ce changement d'expression des sous-unités formant les KATP. Dans notre modèle, nous avons pu montrer que la surexpression de Kirô.l est due aux facteurs de transcription Fox03 et FoxF2 qui est aussi responsable de la surexpression des sous-unités SUR. Dans la dernière partie de ce travail, nous avons mis au point un modèle d'IC in vitro en cultivant les cardiomyocytes de rats adultes en présence d'angiotensine II (Angll) ou de TNFa. Ce modèle expérimental nous a non seulement permis de mettre en relation l'importance de L'AnglI et du TNFa sur le remodelage des canaux KATP mais aussi de développer un modèle in vitro présentant les mêmes caractéristiques que le modèle in vivo concernant le remodelage des KATP lors de l'IC. Ce dernier modèle expérimental ouvre des perspectives afin de mieux caractériser les voies de signalisation impliquées dans le remodelage des canaux KATp lors de l'IC.Conclusion. Les canaux KATp subissent un remodelage lors de l'IC et les résultats obtenus montrent le potentiel cardio-protecteur de ces canaux.ABSTRACT :Background and aim. Cardiovascular disease is the leading cause of death in developed countries and heart failure (HF) is the most common. Following myocardial infarction, the heart of the patient undergoes ventricular remodeling which may evolve toward a state of HF. HF is defined as a state in which heart is unable to supply enough blood to organs and this state is often accompanied by cardiac arrhythmias. Ventricular remodeling involves many genes coding for both metabolic enzymes and ion channels. Changes in ion channel expression can promote arrhythmias responsible for sudden death in patients with HF. A better understanding of the transition between remodeling and HF is crucial in order to prevent the complications associated to HF We were interested in ATP-dependent potassium channels (KATp) because they couple cell metabolism to electrical activity of the cell. Indeed, KATP channels open when the energy charge (ratio of ATP / ADP) of the cell collapses. In cardiomyocytes, the opening of KATP channels induces hyper- polanzation of the cell membrane which reduces calcium overload and thereby protects the cell. KATp channels are composed by 4 Kir6.x subumts (Kir6.1 or Kir6.2) forming the pore channel associated with 4 regulatory subunits SUR. The electrophysiological properties as well as pharmacological sensitivity of KATp channels depend on their composition and only KATP channels formed by Kir6.1 subunit are activated by diazoxide.Methods and results. Firstly, using an in vivo model of HF in adult rats, we showed that Kir6.1 and SUR subunits are overexpressed in HF. In addition, cardiomyocytes from post-infarction hearts became sensitive to diazoxide reflecting the overexpression of the Kir6.1 subunit. The opening of KATP by diazoxide tended to reduce the action potential duration (APD) which is extended in HF. This increase in APD is known to be a major source of arrhythmias during HF. Therefore, the opening of KATP channels by diazoxide would be cardio-protective. Secondly, we wanted to determine which transcription factors were responsible for this KATP remodeling. In our model of HF, we showed that overexpression of Kir6.1 is due to the transcription factors Fox03 and FOXF2 which is also responsible for SUR subunits overexpression. Thirdly, we developed an in vitro model of HF by cultivation of adult rat cardiomyocytes in the presence of angiotensin II (Angll) or TNFa. This model is very interesting not only because it underlines the importance of Angll and TNFa in KATp remodeling but also because this in vitro model presents the same KATP remodeling as the in vivo model of HF. These findings show that our in vitro model of HF opens up many possibilities to investigate more precisely the signaling pathways involved in remodeling of the KATP channels in HF.Conclusion. KATP channels undergo remodeling during HF and our results show the cardio¬protective potential of KATP channels in this disease.

Critical role of the transcriptional repressor neuron-restrictive silencer factor in the specific control of connexin36 in insulin-producing cell lines.

Connexin36 (Cx36) is specifically expressed in neurons and in pancreatic beta-cells. Cx36 functions as a critical regulator of insulin secretion and content in beta-cells. In order to identify the molecular mechanisms that control the beta-cell expression of Cx36, we initiated the characterization of the human 5' regulatory region of the CX36 gene. A 2043-bp fragment of the human CX36 promoter was identified from a human BAC library and fused to a luciferase reporter gene. This promoter region was sufficient to confer specific expression to the reporter gene in insulin-secreting cell lines. Within this 5' regulatory region, a putative neuron-restrictive silencer element conserved between rodent and human species was recognized and binds the neuron-restrictive silencing factor (NRSF/REST). This factor is not expressed in insulin-secreting cells and neurons; it functions as a potent repressor through the recruitment of histone deacetylase to the promoter of neuronal genes. The NRSF-mediated repression of Cx36 in HeLa cells was abolished by trichostatin A, confirming the functional importance of histone deacetylase activity. Ectopic expression, by viral gene transfer, of NRSF/REST in different insulin-secreting beta-cell lines induced a marked reduction in Cx36 mRNA and protein content. Moreover, mutations in the Cx36 neuron-restrictive silencer element relieved the low transcriptional activity of the human CX36 promoter observed in HeLa cells and in INS-1 cells expressing NRSF/REST. The data showed that cx36 gene expression in insulin-producing beta-cell lines is strictly controlled by the transcriptional repressor NRSF/REST indicating that Cx36 participates to the neuronal phenotype of the pancreatic beta-cells.

An HMG-box-containing T-cell factor required for thymocyte differentiation.

Two candidate genes for controlling thymocyte differentiation, T-cell factor-1 (Tcf-1) and lymphoid enhancer-binding factor (Lef-1), encode closely related DNA-binding HMG-box proteins. Their expression pattern is complex and largely overlapping during embryogenesis, yet restricted to lymphocytes postnatally. Here we generate two independent germline mutations in Tcf-1 and find that thymocyte development in (otherwise normal) mutant mice is blocked at the transition from the CD8+, immature single-positive to the CD4+/CD8+ double-positive stage. In contrast to wild-type mice, most of the immature single-positive cells in the mutants are not in the cell cycle and the number of immunocompetent T cells in peripheral lymphoid organs is reduced. We conclude that Tcf-1 controls an essential step in thymocyte differentiation.

Selectively impaired development of intestinal T cell receptor gamma delta+ cells and liver CD4+ NK1+ T cell receptor alpha beta+ cells in T cell factor-1-deficient mice.

T cell factor-1 (Tcf-1) is a transcription factor that binds to a sequence motif present in several T cell-specific enhancer elements. In Tcf-1-deficient (Tcf-1-/-) mice, thymocyte development is partially blocked at the transition from the CD4-8+ immature single-positive stage to the CD4+8+ double-positive stage, resulting in a marked decrease of mature peripheral T cells in lymph node and spleen. We report here that the development of most intestinal TCR gamma delta+ cells and liver CD4+ NK1.1+TCR alpha beta+ (NK1+T) cells, which are believed to be of extrathymic origin, is selectively impaired in Tcf-1-/- mice. In contrast, thymic and thymus-derived (splenic) TCR gamma delta+ cells are present in normal numbers in Tcf-1-/- mice, as are other T cell subsets in intestine and liver. Collectively, our data suggest that Tcf-1 is differentially required for the development of some extrathymic T cell subsets, including intestinal TCR gamma delta+ cells and liver CD4+ NK1+T cells.

Genetic characterisation of Langerin gene in human immunodeficiency virus-1-infected women from Bahia, Brazil

Studies on human genetic variations are a useful source of knowledge about human immunodeficiency virus (HIV)-1 infection. The Langerin protein, found at the surface of Langerhans cells, has an important protective role in HIV-1 infection. Differences in Langerin function due to host genetic factors could influence susceptibility to HIV-1 infection. To verify the frequency of mutations in the Langerin gene, 118 samples from HIV-1-infected women and 99 samples from HIV-1-uninfected individuals were selected for sequencing of the promoter and carbohydrate recognition domain (CRD)-encoding regions of the Langerin gene. Langerin promoter analysis revealed two single nucleotide polymorphisms (SNPs) and one mutation in both studied groups, which created new binding sites for certain transcription factors, such as NFAT5, HOXB9.01 and STAT6.01, according to MatInspector software analysis. Three SNPs were observed in the CRD-encoding region in HIV-1-infected and uninfected individuals: p.K313I, c.941C>T and c.983C>T. This study shows that mutations in the Langerin gene are present in the analysed populations at different genotypic and allelic frequencies. Further studies should be conducted to verify the role of these mutations in HIV-1 susceptibility.