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Results for “Enhancer mapping”

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PubMed2026

Optical genome mapping enhanced by refined variant interpretation in pediatric acute lymphoblastic leukemia.

Reliable detection of structural variants (SVs) and copy number variations (CNVs) is crucial in the contemporary diagnostics of pediatric B-cell acute lymphoblastic leukemia (B-ALL). However, limitations of commonly used conventional and molecular cytogenetic methods may hinder the accurate genetic characterization of patients. Optical genome mapping (OGM) offers a reliable alternative by enabling high-resolution, genome-wide detection of CNVs and SVs. Chromosomal aberrations were screened using OGM in 51 children with B-ALL. The results were compared with those of karyotyping, fluorescence in situ hybridization (FISH), digital multiplex ligation-dependent probe amplification (digitalMLPA), and targeted RNA sequencing (RNA-seq). OGM data showed high congruency with karyotyping and FISH findings, detecting clinically relevant variants beyond G-banding results and unraveling a complex KMT2A fusion undetected by FISH. Gene fusions involved in complex ETV6::RUNX1 translocations, but not detected by RNA-seq, were confirmed using FISH. Normalization of OGM copy number values with DNA-index-improved concordance with FISH-derived copy numbers in near-tri/tetraploid cases. In the peripheral regions of OGM variants (fringe-zones), a novel evaluation strategy called 'FriZone' was applied, which significantly improved the concordance between OGM and digitalMLPA. In addition, a co-segregation analysis revealed strong associations between ETV6::RUNX1 fusion and deletions of ETV6, RAG2, and NR3C2. OGM uncovered complex rearrangements undetected by widely used methods in 15% of cases, improving genetic classification and risk stratification in 10% of the patients. The FriZone analysis and normalization by DNA-index provide a refined, more accurate approach to OGM variant interpretation, facilitating the efficient application of OGM in clinical diagnostics. © 2026 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Humans↗

PubMed2026

Combining neuromelanin-sensitive MRI and quantitative susceptibility mapping for enhanced diagnosis and differentiation of parkinson's disease: A systematic review.

BACKGROUND: Loss of dopaminergic neurones and iron deposition in the substantia nigra pars compacta (SNpc) are two major pathological hallmarks of Parkinson's disease (PD). Such changes can be visualised by advanced techniques including neuromelanin-sensitive MRI (NM-MRI) and quantitative susceptibility mapping (QSM). This systematic review investigates the diagnostic performance and methodological development of the integrated use of NM-MRI and QSM in PD. METHODS: The systematic search was performed in four databases (Scopus, PubMed, ScienceDirect, and Web of Science) according to the PRISMA 2020 guidelines until July 2026. Bias was assessed using QUADAS-2 and certainty of evidence was assessed using GRADE. RESULTS: Seventeen studies with 2228 participants were included. Combined NM-MRI and QSM consistently showed reduced neuromelanin volume/contrast and increased iron deposition in the SNpc of PD patients compared to healthy controls. Multimodal integration yielded a significant improvement in diagnostic accuracy (AUC values 0.86-0.99), and was able to successfully differentiate PD. Recent methodological advances included simultaneous acquisition sequences (e.g. MTC-GRE, STAGE, setMag) and AI-driven automated segmentation, which led to significantly reduced scan times and improved reproducibility. CONCLUSION: The combination of NM-MRI and QSM has a synergistic effect and provides powerful complementary biomarkers for the diagnosis and differential diagnosis of PD.

Humans↗

PubMed2003

1-Mb resolution array-based comparative genomic hybridization using a BAC clone set optimized for cancer gene analysis.

Array-based comparative genomic hybridization (aCGH) is a recently developed tool for genome-wide determination of DNA copy number alterations. This technology has tremendous potential for disease-gene discovery in cancer and developmental disorders as well as numerous other applications. However, widespread utilization of a CGH has been limited by the lack of well characterized, high-resolution clone sets optimized for consistent performance in aCGH assays and specifically designed analytic software. We have assembled a set of approximately 4100 publicly available human bacterial artificial chromosome (BAC) clones evenly spaced at approximately 1-Mb resolution across the genome, which includes direct coverage of approximately 400 known cancer genes. This aCGH-optimized clone set was compiled from five existing sets, experimentally refined, and supplemented for higher resolution and enhancing mapping capabilities. This clone set is associated with a public online resource containing detailed clone mapping data, protocols for the construction and use of arrays, and a suite of analytical software tools designed specifically for aCGH analysis. These resources should greatly facilitate the use of aCGH in gene discovery.

Cell Line, Tumor↗

PubMed2027

Mapping Stage-Specific Enhancer Dynamics During the Specification of Human Trophoblast Lineage.

Chromatin immunoprecipitation followed by next-generation sequencing (ChIP-seq) is a powerful technique for mapping cis-acting regulatory elements in DNA regions, such as enhancers and promoters, that are associated with specific histone modification marks or bound by transcription factors (TFs). By systematically mapping enhancer landscapes across various cell types or differentiation trajectories, this methodology facilitates the discovery of highly regulated genes specific to certain cell types, as well as the underlying transcriptional and epigenetic regulatory mechanisms that establish cellular identity and function. Particular emphasis has been placed on mapping large clusters of enhancers known as super-enhancers (SEs), which are often associated with cell-type-specific master TFs. Unlike typical enhancers, SEs can help to identify previously unknown key TFs specific to certain cell types. Follow-up studies can systematically validate these master regulators and their mechanisms of action, providing a comprehensive framework for deciphering the regulatory architecture underlying cellular identity. This protocol outlines how to map dynamic changes in enhancer and SE usage during human trophoblast differentiation using human trophoblast stem cells (TSCs) and their subsequent differentiation into more specialized cell types.

Humans↗

PubMed2026

Enhancer-promoter interaction maps in pig implantation tissue identify candidate cis-regulatory elements and regulatory variants.

Due to the polygenic nature of pig reproductive traits, most variants accounting for the phenotypic variation remain poorly characterized. It is well established that trait-associated variants are often enriched in regulatory elements of relevant tissues, and coordinated endometrial-conceptus crosstalk is critical for implantation success. Accordingly, this study aimed to investigate the chromatin landscape in pig endometrium-conceptus tissues and identify regulatory variants associated with reproductive traits. Combining RNA-seq and ChIP-seq, we uncovered cis-regulatory elements whose histone modification patterns correlate with gene expression. H3K27ac-based chromatin interaction profiling further resolved 2137 cis-regulatory elements involved in enhancer-promoter (E-P) interactions. Subsequent analyses identified candidate variants within these regulatory regions that associate with reproductive traits, in which the enhancer SNP rs346038249 likely affects transcriptional activity through allele-dependent transcription factor binding. Collectively, our findings provide mechanistic insights into pig embryo implantation and nominate candidate regulatory variants that merit further functional validation for their potential role in pig genetic improvement.

Embryo implantation↗

PubMed2025

Chromosome-level genome assembly and annotation of Petunia hybrida.

Petunia hybrida is the world's most popular garden plant and is regarded as a supermodel for studying the biology associated with the Asterid clade, the largest of the two major groups of flowering plants. Unlike other Solanaceae, petunia has a base chromosome number of seven, not 12. This along with recombination suppression has previously hindered efforts to assemble its genome to chromosome level. Here we achieve a chromosome-level assembly for P. hybrida using a combination of short-read and long-read sequencing, optical mapping (Bionano) and Hi-C technologies. The resulting assembly spans 1253.6 Mb with a BUSCO score of 99.8%. A total of 35,089 genes were predicted and of those 29,655 were functionally annotated. Syntenic regions between petunia, tomato and pepper were identified, highlighting rearrangements that have occurred since their divergence indicating that the 12 chromosomes of Solanaceae did not originate from whole genome duplication of an ancestral species with seven chromosomes like petunia. This assembly will enhance trait mapping efficiency and serve as a valuable resource for functional genomic studies.

Petunia↗

PubMed2026

Multimodal atlas of human atherosclerosis links granular vascular cell states to coronary artery disease risk.

Advances in single-cell and spatial assays have revolutionized the scale and resolution of molecular tissue profiling. Here we present MetaPlaq, a multimodal atlas of human atherosclerotic arterial beds comprising over a million cells across single-cell transcriptomics, epigenomics and high-resolution spatial expression assays. We map granular cell states and disease-relevant transcriptional programs within the native tissue context of coronary arteries. Furthermore, we map cardiovascular GWAS signals to smooth muscle cells (SMCs) and endothelial cells (ECs) and uncover the cis-regulatory architecture governing their phenotypic transitions. Our comprehensive epigenomic reference allowed us to build cell-specific enhancer-gene link maps and multimodal gene regulatory networks (GRNs) underlying disease-relevant states such as osteogenic SMCs and ECs undergoing mesenchymal transition. We also integrate SMC and EC disease-associated gene sets with GRNs to nominate key transcription factors such as PRRX1, BNC2 and ELK3 regulating atherosclerosis-relevant transcriptional programs. Finally, we layer single-cell and spatial modalities to fine-map GWAS variants with improved cell and anatomical context. We highlight candidate cell-specific regulatory mechanisms at less characterized CAD loci, including FGD5 and MCF2L in ECs. Together, this atlas represents an important step towards fully interpreting genetic risk loci and informing new therapeutic strategies for cardiovascular disease.

Journal Article↗

PubMed2025

Integrative Genomic, Transcriptomic and Epigenomic Analysis Reveals cis-regulatory Contributions to High-altitude Adaptation in Tibetan Pigs.

The Qinghai-Tibet Plateau, characterized by its extreme environmental conditions, presents significant challenges to life, making it an ideal region for studying adaptation and evolution. Tibetan pigs, known for their high genetic diversity and exceptional adaptability to high altitudes, serve as excellent models for investigating high-altitude adaptation. While previous studies have extensively identified genetic determinants associated with high-altitude adaptation, the molecular mechanisms, particularly cis-regulatory patterns, remain poorly understood. Here, we conducted a selective sweep analysis using 484 genomes from Chinese and Western pig breeds across various altitudes, revealing 38.56 Mb of genomic regions under selection in Tibetan pigs. Enrichment analysis identified the lung as the primary functional tissue involved in high-altitude adaptation, supported by tissue-specific transcriptional and regulatory patterns observed between Tibetan and Meishan pigs (low altitude). By integrating genomic, RNA-seq, ATAC-seq, and H3K27ac HiChIP data, we constructed comprehensive enhancer-promoter regulatory maps of candidate genes and pinpointed promising genetic determinants associated with high-altitude adaptation, including SNPs in EPAS1, KLF13, SPRED1, and CFD. These loci were predicted to influence chromatin accessibility and the interactions of regulatory elements, with altered binding strength of relevant transcription factors. Further in vitro experiments confirmed that these loci function as allele-specific enhancers, modulating the expression of target genes. Our findings elucidate the regulatory basis of high-altitude adaptation in Tibetan pigs and provide valuable insights for exploring hypoxia-related diseases in livestock and humans.

Animals↗

PubMed2026

Long-read sequencing resolves complex CYP21A2 variants and identifies 2+0 carriers in 21-hydroxylase deficiency.

The complex CYP21A2 variants arising from high homology with its pseudogene CYP21A1P challenge the diagnosis of 21-hydroxylase deficiency (21-OHD). This study systematically evaluated long-read sequencing (LRS) for identifying complex structural variants of the CYP21A2 gene in 21-OHD in comparison with conventional molecular diagnostic methods, including multiplex ligation-dependent probe amplification (MLPA), CNVplex, and SNaPshot. Twenty patients with suspected 21-OHD and defined CYP21A2 structural variants identified via initial MLPA screening were enrolled. Variants were further analyzed using CNVplex and SNaPshot, then all samples underwent LRS for comprehensive variant detection, breakpoint mapping, and haplotype resolution. LRS overcame key limitations of conventional methods. It reliably identified a novel large-fragment deletion and defined its boundaries. Notably, LRS identified "2+0" carriers, where deletions masked by duplications cause false-negatives with standard techniques. Moreover, LRS accurately distinguished CYP21A1P/CYP21A2_CH-4 and CH-9 chimera subtypes which were indistinguishable by the combined conventional assays. Furthermore, LRS enabled the precise identification and characterization of TNXA/TNXB chimeric deletions. These are frequently misclassified as CYP21A1P/CYP21A2 chimeras by conventional methods but are critical for diagnosing associated conditions such as CAH-X syndrome. LRS provides a superior, integrated solution for the molecular diagnosis of 21-OHD, offering precise structural variant characterization, accurate carrier detection, and reliable breakpoint mapping. Its application enhances diagnostic accuracy, supports advanced genetic counseling, and paves the way for genotype-informed clinical management.

Journal Article↗

PubMed2023

Genome-wide identification of transcriptional enhancers during human placental development and association with function, differentiation, and disease†.

The placenta is a dynamic organ that must perform a remarkable variety of functions during its relatively short existence in order to support a developing fetus. These functions include nutrient delivery, gas exchange, waste removal, hormone production, and immune barrier protection. Proper placenta development and function are critical for healthy pregnancy outcomes, but the underlying genomic regulatory events that control this process remain largely unknown. We hypothesized that mapping sites of transcriptional enhancer activity and associated changes in gene expression across gestation in human placenta tissue would identify genomic loci and predicted transcription factor activity related to critical placenta functions. We used a suite of genomic assays [i.e., RNA-sequencing (RNA-seq), Precision run-on-sequencing (PRO-seq), and Chromatin immunoprecipitation-sequencing (ChIP-seq)] and computational pipelines to identify a set of >20 000 enhancers that are active at various time points in gestation. Changes in the activity of these enhancers correlate with changes in gene expression. In addition, some of these enhancers encode risk for adverse pregnancy outcomes. We further show that integrating enhancer activity, transcription factor motif analysis, and transcription factor expression can identify distinct sets of transcription factors predicted to be more active either in early pregnancy or at term. Knockdown of selected identified transcription factors in a trophoblast stem cell culture model altered the expression of key placental marker genes. These observations provide a framework for future mechanistic studies of individual enhancer-transcription factor-target gene interactions and have the potential to inform genetic risk prediction for adverse pregnancy outcomes.

Humans↗

PubMed2026

Artificial intelligence-derived myocardial fibrosis on cardiac magnetic resonance for prognosis in cardiomyopathy: A systematic review of a sparse evidence base.

BACKGROUND: Myocardial fibrosis on cardiovascular magnetic resonance (CMR), assessed by late gadolinium enhancement (LGE) and parametric mapping, is an established predictor of adverse events in cardiomyopathy. We assessed whether artificial intelligence (AI) quantification of fibrosis adds independent prognostic value. METHODS: We searched six databases, a clinical-trials register, and a preprint server from inception to 13 June 2026. Eligible studies used AI to generate a fibrosis marker in adults with ischemic or nonischemic cardiomyopathy, with covariate-adjusted outcomes over ≥12 months. Risk of bias was assessed using PROBAST, PROBAST+AI, and QUIPS. Fewer than three comparable studies precluded meta-analysis; certainty was rated using GRADE. RESULTS: Of 448 records (381 after de-duplication), 18 full texts were reviewed and two included, one peer-reviewed and one preprint. In an ischemic-cardiomyopathy registry (Ghanbari et al.; n = 216 analytic, 26 events), AI-derived dense LGE scar predicted arrhythmic events (univariable hazard ratio [HR] 2.35, 95% CI 1.33-4.15), and AI-derived but not manual scar improved discrimination beyond guideline criteria (area under the curve 0.63 to 0.68; p = 0.02). In a nonischemic dilated-cardiomyopathy preprint (Kim et al.; n = 347, 119 events), automated extracellular volume ≥30% predicted cardiovascular death or heart-failure hospitalization (adjusted HR 2.00, 95% CI 1.32-3.03). Both were at high risk of bias, with data-derived thresholds and no external validation. CONCLUSIONS: Across only two studies, AI-derived fibrosis was independently associated with adverse cardiovascular events, but its added value over manual quantification remains unproven. Certainty was very low. The evidence base is sparse and not yet ready for clinical use.

Humans↗

PubMed2025

Predicting telomerase reverse transcriptase promoter mutation status in glioblastoma by whole-tumor multi-sequence magnetic resonance texture analysis.

OBJECTIVE: This study aimed to determine the feasibility of preoperative multi-sequence magnetic resonance texture analysis (MRTA) for predicting TERT promoter mutation status in IDH-wildtype glioblastoma (IDHwt GB). METHODS: The clinical and imaging data of 111 patients with IDHwt GB at our hospital between November 2018 and June 2023 were retrospectively analyzed as the training set, and those of 23 patients with IDHwt GB between July 2023 and November 2023 were interpreted as the validation set. We used molecular sequencing results to classify the training set into TERT promoter mutation and wildtype groups. Textural features of the whole-tumor volume were extracted, including T2-weighted imaging (T2WI), T2-fluid-attenuated inversion recovery, apparent diffusion coefficient (ADC) map, and contrast-enhanced T1-weighted imaging (CE-T1). All textural features were obtained using open-source pyradiomics. After feature selection, logistic regression was used to build prediction models, and a nomogram was generated. Finally, the model was validated using validation cohort. RESULTS: The CE-T1_Model (AUC 0.704) had a better predictive ability than the T2_Model (AUC 0.684) and ADC_Model (AUC 0.624). The MRI_Combined_Model (CE-T1, T2, and ADC texture features) (AUC 0.780) had a better predictive ability than the Clinical_Model (AUC 0.758). The Combined_Model (CE-T1, T2, ADC texture features, and clinical features) had the best predictive performance (AUC 0.871), with a sensitivity, specificity, and accuracy of 82.60 %, 83.30 %, and 80.18 %, respectively. The AUC, sensitivity, specificity, and accuracy in the validation cohort were 0.775, 86.70 %, 75.00 %, and 69.57 %, respectively. CONCLUSIONS: Whole-tumor multi-sequence MRTA can be used as non-invasive quantitative parameters to assist in the preoperative clinical prediction of TERT promoter mutation status in IDHwt GB.

Humans↗

PubMed2025

Genetic-epigenetic interactions (meQTLs) in orofacial clefts etiology.

OBJECTIVES: Nonsyndromic orofacial clefts (OFCs) involve complex genetic and environmental factors, with over 60 risk loci accounting for only a minority of estimated heritability and residing in non-coding regions with unclear functional relevance. We hypothesize that some genetic variants alter orofacial cleft risk by modifying DNA methylation (DNAm) at regulatory sequences essential for craniofacial development, acting as methylation quantitative trait loci (meQTLs). METHODS: We analyzed 10 well-established OFC-associated SNPs against genome-wide DNAm profiles in 409 cases and 456 controls, identifying 23 potential meQTLs. We validated findings using 358 cleft-discordant sibling pairs analyzed with quantitative MethyLight assays. Cross-referencing with the mQTL Database assessed temporal patterns across human development. Functional annotation used GeneHancer and craniofacial enhancer databases. RESULTS: Nine meQTLs were successfully replicated, including the highly significant rs987525 (8q24) - cg16561172 (MYC) association (P = 9.610E-6). This association mapped to a mesendoderm-active enhancer upstream of MYC, providing mechanistic explanation for the longstanding 8q24 cleft locus. Additional validated associations involved MAFB-PLCG1, NOG-PPM1E, FOXE1-FRZB, and SPRY2-LGR4 interactions. Independent differential methylation analysis revealed significant differences between discordant siblings at three CpG sites. Cross-referencing confirmed concordance with population-level methylation effects, with childhood representing the critical developmental window for most associations. CONCLUSIONS: This systematic meQTL characterization in OFCs demonstrates that genetic variants influence disease risk through epigenetic mechanisms. The 8q24-MYC regulatory pathway evidence provides crucial mechanistic insight into a major OFC risk locus. These findings bridge genetic associations with functional consequences, address missing heritability challenges, and suggest potential biomarkers and therapeutic targets for OFC prevention and treatment.

Journal Article↗

PubMed2025

H3K4me2 distinguishes a distinct class of enhancers during the maternal-to-zygotic transition.

After egg fertilization, an initially silent embryonic genome is transcriptionally activated during the maternal-to-zygotic transition. In zebrafish, maternal vertebrate pluripotency factors Nanog, Pou5f3 (OCT4 homolog), and Sox19b (SOX2 homolog) (NPS) play essential roles in orchestrating embryonic genome activation, acting as "pioneers" that open condensed chromatin and mediate acquisition of activating histone modifications. However, some embryonic gene transcription still occurs in the absence of these factors, suggesting the existence of other mechanisms regulating genome activation. To identify chromatin signatures of these unknown pathways, we profiled the histone modification landscape of zebrafish embryos using CUT&RUN. Our regulatory map revealed two subclasses of enhancers distinguished by presence or absence of H3K4me2. Enhancers lacking H3K4me2 tend to require NPS factors for de novo activation, while enhancers bearing H3K4me2 are epigenetically bookmarked by DNA hypomethylation to recapitulate gamete activity in the embryo, independent of NPS pioneering. Thus, parallel enhancer activation pathways combine to induce transcriptional reprogramming to pluripotency in the early embryo.

Animals↗

PubMed2022

Enhancer and super-enhancer landscape in polycystic kidney disease.

Widespread aberrant gene expression is a pathological hallmark of polycystic kidney disease (PKD). Numerous pathogenic signaling cascades, including c-Myc, Fos, and Jun, are transactivated. However, the underlying epigenetic regulators are poorly defined. Here we show that H3K27ac, an acetylated modification of DNA packing protein histone H3 that marks active enhancers, is elevated in mouse and human samples of autosomal dominant PKD. Using comparative H3K27ac ChIP-Seq analysis, we mapped over 16000 active intronic and intergenic enhancer elements in Pkd1-mutant mouse kidneys. We found that the cystic kidney epigenetic landscape resembles that of a developing kidney, and over 90% of upregulated genes in Pkd1-mutant kidneys are co-housed with activated enhancers in the same topologically associated domains. Furthermore, we identified an evolutionarily conserved enhancer cluster downstream of the c-Myc gene and super-enhancers flanking both Jun and Fos loci in mouse and human models of autosomal dominant PKD. Deleting these regulatory elements reduced c-Myc, Jun, or Fos abundance and suppressed proliferation and 3D cyst growth of Pkd1-mutant cells. Finally, inhibiting glycolysis and glutaminolysis or activating Ppara in Pkd1-mutant cells lowerd global H3K27ac levels and its abundance on c-Myc enhancers. Thus, our work suggests that epigenetic rewiring mediates the transcriptomic dysregulation in PKD, and the regulatory elements can be targeted to slow cyst growth.

Animals↗

PubMed2025

Enhancer-targeting CRISPR screens at coronary artery disease loci suggest shared mechanisms of disease risk.

To systematically identify causal genetic mechanisms that confer risk for coronary artery disease (CAD) in GWAS loci, we mapped genome-wide variant-to-enhancer-to-gene (V2E2G) links in vascular smooth muscle cells (SMC). Enhancers identified by active chromatin features, and further prioritized by base-resolution deep learning models of chromatin accessibility in 108 CAD loci, were studied with CRISPRi targeting and Direct-Capture Targeted Perturb-seq (DC-TAP-seq) evaluation of 470 genes. Seventy-six V2E2G links were identified for 59 candidate CAD genes representing gene programs including epithelial-mesenchymal transformation, ubiquitination, and protein folding as well as BMP and TGFB signaling. Similar methods employed with an independent focused screen targeting one candidate locus at 9p21.3 identified 10 enhancers regulating expression of multiple genes at this location. Detailed molecular studies revealed that two enhancers mediating transcription factor binding and transcriptional regulation contribute to ancestry-specific and sex-specific risk for CAD and the surrogate biomarker vascular calcification. Together, these studies advance our identification of GWAS CAD V2E2G links across the genome, and specific mechanisms of risk at the complex 9p21.3 locus.

Journal Article↗

PubMed2026

Heat shock protein 40 enhances axon regeneration in a mouse model of traumatic optic neuropathy.

Retinal ganglion cell death occurs following injury to the optic nerve either by trauma or in disease such as glaucoma, leading to severe vision loss. Recent innovations have demonstrated that optic nerve regeneration is feasible; however, the regeneration is limited. The aim of the present study is to identify genomic elements enhancing axon regeneration. We have taken a forward genetics approach using the BXD recombinant mouse strains to identify a gene that increases the extent of optic nerve regeneration. Axon regeneration was induced by knocking down Pten in retinal ganglion cells using adeno-associated virus to deliver an shRNA followed by an intravitreal injection of Zymosan with CPT-cAMP that produced a mild inflammatory response. Retinal ganglion cell axons were damaged by optic nerve crush. Following a 12-day survival period, regenerating axons were labeled by intravitreal injection of Cholera Toxin B conjugated with Alexa Fluor 647. Two days later, labeled axons within the optic nerve were examined to determine the number of regenerating axons and the distance they traveled down the optic nerve. The analysis revealed a surprising difference in the amount of axonal regeneration across all 33 BXD strains. There was a 7.5-fold difference in the number of regenerating axons and a 4-fold difference in the distance traveled by regenerating axons. These data were used to generate an interval map defining genomic loci that modulate enhanced axonal regeneration. A quantitative trait locus modulating axon regeneration was identified on Chromosome 14 (115 to 119 Mb). Within this locus were 16 annotated genes. Subsequent testing revealed that one candidate gene, Dnajc3, modulated axonal regeneration. Dnajc3 encodes heat shock protein 40 (HSP40), a molecular chaperone. Knocking down Dnajc3 in the high regenerative strain (BXD90) led to a decreased regeneration response, whereas, overexpression of Dnajc3 in a low regenerative strain (BXD34) resulted in an increased regeneration response. These findings reveal that Dnajc3 not only increases the number of regenerating axons, but also increases the distance that axons travel. The enhanced regeneration will prove to be critical for functional recovery in humans, where the distance axons travel to their targets is considerably longer than that of mice.

axon regeneration↗

PubMed2026

Genetic-epigenetic interactions (meQTLs) in orofacial clefts etiology.

Understanding how genetic variants influence disease risk through molecular mechanisms remains a central challenge in complex disease genetics. Nonsyndromic orofacial clefts (OFCs) exemplify this challenge, with most risk loci residing in non-coding regions. We hypothesized that common genetic variants influence OFC risk by modulating DNA methylation at regulatory elements through methylation quantitative trait loci (meQTLs). We analyzed 10 OFC-associated SNPs against genome-wide DNA methylation profiles in 409 cases and 456 controls, identifying 23 potential meQTLs. Findings were validated using 358 cleft-discordant sibling pairs with MethyLight assays. We performed formal mediation analysis, genotype-tissue interaction and cross-referenced with the mQTL Database to assess developmental timing. Nine meQTLs were validated, including rs987525 (8q24)-cg16561172 (MYC) (P = 9.6 × 10⁻⁶), which mapped to a mesendoderm-active enhancer upstream of MYC. Genotype × tissue interaction confirmed tissue-specificity (P = 1.00 × 10- 3), with stronger effects in oral-derived tissue (saliva). Additional validated SNP-CpG associations involved MAFB-PLCG1, NOG-PPM1E, FOXE1-FRZB, and SPRY2-LGR4. While effect sizes correlated between tissues (r = 0.81), formal mediation analysis indicated individual CpG sites do not fully mediate SNP-phenotype relationships, suggesting coordinated epigenetic mechanisms. Most associations showed peak effects during childhood, while 8q24 showed unique adult-specific patterns. We identified genetic variants influencing methylation at craniofacial regulatory elements, and provided a mechanistic link for a major risk locus, 8q24, with tissue-specific effects in saliva. While individual CpG sites did not fully mediate the genetic risk, our findings identified specific regulatory regions where coordinated epigenetic changes may contribute to OFC susceptibility.

Humans↗