Generation of tamoxifen-inducible Tfap2b-CreERT2 mice using CRISPR-Cas9.

Tfap2b, a pivotal transcription factor, plays critical roles within neural crest cells and their derived lineage. To unravel the intricate lineage dynamics and contribution of these Tfap2b+ cells during craniofacial development, we established a Tfap2b-CreERT2 knock-in transgenic mouse line using the CRISPR-Cas9-mediated homologous direct repair. By breeding with tdTomato reporter mice and initiating Cre activity through tamoxifen induction at distinct developmental time points, we show the Tfap2b lineage within the key neural crest-derived domains, such as the facial mesenchyme, midbrain, cerebellum, spinal cord, and limbs. Notably, the migratory neurons stemming from the dorsal root ganglia are visible subsequent to Cre activity initiated at E8.5. Intriguingly, Tfap2b+ cells, serving as the progenitors for limb development, show activity predominantly commencing at E10.5. Across the mouse craniofacial landscape, Tfap2b exhibits a widespread presence throughout the facial organs. Here we validate its role as a marker of progenitors in tooth development and have confirmed that this process initiates from E12.5. Our study not only validates the Tfap2b-CreERT2 transgenic line, but also provides a powerful tool for lineage tracing and genetic targeting of Tfap2b-expressing cells and their progenitor in a temporally and spatially regulated manner during the intricate process of development and organogenesis.

Human Genetics of Ventricular Septal Defect.

Ventricular septal defects (VSDs) are recognized as one of the commonest congenital heart diseases (CHD), accounting for up to 40% of all cardiac malformations, and occur as isolated CHDs as well as together with other cardiac and extracardiac congenital malformations in individual patients and families. The genetic etiology of VSD is complex and extraordinarily heterogeneous. Chromosomal abnormalities such as aneuploidy and structural variations as well as rare point mutations in various genes have been reported to be associated with this cardiac defect. This includes both well-defined syndromes with known genetic cause (e.g., DiGeorge syndrome and Holt-Oram syndrome) and so far undefined syndromic forms characterized by unspecific symptoms. Mutations in genes encoding cardiac transcription factors (e.g., NKX2-5 and GATA4) and signaling molecules (e.g., CFC1) have been most frequently found in VSD cases. Moreover, new high-resolution methods such as comparative genomic hybridization enabled the discovery of a high number of different copy number variations, leading to gain or loss of chromosomal regions often containing multiple genes, in patients with VSD. In this chapter, we will describe the broad genetic heterogeneity observed in VSD patients considering recent advances in this field.

Tfap2a is a novel gatekeeper of nephron differentiation during kidney development.

Renal functional units known as nephrons undergo patterning events during development that create a segmental array of cellular compartments with discrete physiological identities. Here, from a forward genetic screen using zebrafish, we report the discovery that transcription factor AP-2 alpha (tfap2a) coordinates a gene regulatory network that activates the terminal differentiation program of distal segments in the pronephros. We found that tfap2a acts downstream of Iroquois homeobox 3b (irx3b), a distal lineage transcription factor, to operate a circuit consisting of tfap2b, irx1a and genes encoding solute transporters that dictate the specialized metabolic functions of distal nephron segments. Interestingly, this regulatory node is distinct from other checkpoints of differentiation, such as polarity establishment and ciliogenesis. Thus, our studies reveal insights into the genetic control of differentiation, where tfap2a is essential for regulating a suite of segment transporter traits at the final tier of zebrafish pronephros ontogeny. These findings have relevance for understanding renal birth defects, as well as efforts to recapitulate nephrogenesis in vivo to facilitate drug discovery and regenerative therapies.

Mutations in TFAP2B and previously unimplicated genes of the BMP, Wnt, and Hedgehog pathways in syndromic craniosynostosis.

Craniosynostosis (CS) is a frequent congenital anomaly featuring the premature fusion of 1 or more sutures of the cranial vault. Syndromic cases, featuring additional congenital anomalies, make up 15% of CS. While many genes underlying syndromic CS have been identified, the cause of many syndromic cases remains unknown. We performed exome sequencing of 12 syndromic CS cases and their parents, in whom previous genetic evaluations were unrevealing. Damaging de novo or transmitted loss of function (LOF) mutations were found in 8 genes that are highly intolerant to LOF mutation (P = 4.0 × 10-8); additionally, a rare damaging mutation in SOX11, which has a lower level of intolerance, was identified. Four probands had rare damaging mutations (2 de novo) in TFAP2B, a transcription factor that orchestrates neural crest cell migration and differentiation; this mutation burden is highly significant (P = 8.2 × 10-12). Three probands had rare damaging mutations in GLI2, SOX11, or GPC4, which function in the Hedgehog, BMP, and Wnt signaling pathways; other genes in these pathways have previously been implicated in syndromic CS. Similarly, damaging de novo mutations were identified in genes encoding the chromatin modifier KAT6A, and CTNNA1, encoding catenin α-1. These findings establish TFAP2B as a CS gene, have implications for assessing risk to subsequent children in these families, and provide evidence implicating other genes in syndromic CS. This high yield indicates the value of performing exome sequencing of syndromic CS patients when sequencing of known disease loci is unrevealing.

Evaluation of Ductal Tissue in Coarctation of the Aorta Using X-Ray Phase-Contrast Tomography.

We assessed the histological accuracy of X-ray phase-contrast tomography (XPCT) and investigated three-dimensional (3D) ductal tissue distribution in coarctation of the aorta (CoA) specimens. We used nine CoA samples, including the aortic isthmus, ductus arteriosus (DA), and their confluences. 3D images were obtained using XPCT. After scanning, the samples were histologically evaluated using elastica van Gieson (EVG) staining and transcription factor AP-2 beta (TFAP2B) immunostaining. XPCT sectional images clearly depicted ductal tissue distribution as low-density areas. In comparison with EVG staining, the mass density of the aortic wall positively correlated with elastic fiber formation (R = 0.69, P < 0.001). TFAP2B expression was consistent with low-density area including intimal thickness on XPCT images. On 3D imaging, the distances from the DA insertion to the distal terminal of the ductal media and to the intima on the ductal side were 1.63 ± 0.22 mm and 2.70 ± 0.55 mm, respectively. In the short-axis view, the posterior extension of the ductal tissue into the aortic lumen was 79 ± 18% of the diameter of the descending aorta. In three specimens, the aortic wall was entirely occupied by ductal tissue. The ductal intima spread more distally and laterally than the ductal media. The contrast resolution of XPCT images was comparable to that of histological assessment. Based on the 3D images, we conclude that complete resection of intimal thickness, including the opposite side of the DA insertion, is required to eliminate residual ductal tissue and to prevent postoperative re-coarctation.

Transcription factor TFAP2B up-regulates human corneal endothelial cell-specific genes during corneal development and maintenance.

The corneal endothelium, which originates from the neural crest via the periocular mesenchyme (PM), is crucial for maintaining corneal transparency. The development of corneal endothelial cells (CECs) from the neural crest is accompanied by the expression of several transcription factors, but the contribution of some of these transcriptional regulators to CEC development is incompletely understood. Here, we focused on activating enhancer-binding protein 2 (TFAP2, AP-2), a neural crest-expressed transcription factor. Using semiquantitative/quantitative RT-PCR and reporter gene and biochemical assays, we found that, within the AP-2 family, the TFAP2B gene is the only one expressed in human CECs in vivo and that its expression is strongly localized to the peripheral region of the corneal endothelium. Furthermore, the TFAP2B protein was expressed both in vivo and in cultured CECs. During mouse development, TFAP2B expression began in the PM at embryonic day 11.5 and then in CECs during adulthood. siRNA-mediated knockdown of TFAP2B in CECs decreased the expression of the corneal endothelium-specific proteins type VIII collagen α2 (COL8A2) and zona pellucida glycoprotein 4 (ZP4) and suppressed cell proliferation. Of note, we also found that TFAP2B binds to the promoter of the COL8A2 and ZP4 genes. Furthermore, CECs that highly expressed ZP4 also highly expressed both TFAP2B and COL8A2 and showed high cell proliferation. These findings suggest that TFAP2B transcriptionally regulates CEC-specific genes and therefore may be an important transcriptional regulator of corneal endothelial development and homeostasis.

A novel missense mutation in TFAP2B associated with Char syndrome and central diabetes insipidus.

Char syndrome is characterized by persistent patent ductus arteriosus (PDA) associated with hand-skeletal abnormalities and distinctive facial dysmorphism. Pathogenic variants in the transcription factor gene TFAP2B have been shown to cause Char syndrome; however, there is significant phenotypic variability linked to variant location. Here, we report a pediatric patient with a novel de novo variant in the fifth exon of TFAP2B, c.917C > T (p.Thr306Met), who presented with PDA, patent foramen ovale, postaxial polydactyly of the left fifth toe and clinodactyly of the left fourth toe, sensorineural hearing loss, scoliosis, dental anomalies, and central diabetes insipidus (CDI). CDI, scoliosis, and hearing loss have not previously been reported in a patient with Char syndrome, and while the association may be coincidental, this report expands the genotypes and potentially phenotypes associated with this syndrome.

Decreased expression of TFAP2B in endometrial cancer predicts poor prognosis: A study based on TCGA data.

BACKGROUND: Transcription factor activator protein-2ß (TFAP-2ß) was previously reported to constituted promoter activity in endometrial carcinoma (EC). We evaluated the role of TFAP2B in ECs using publicly available data from The Cancer Genome Atlas (TCGA). METHODS: The relationship between clinical pathologic features and TFAP2B were analyzed with the Wilcoxon signed-rank test and logistic regression. Clinicopathologic characteristics associated with overall survival in TCGA patients using Cox regression and the Kaplan-Meier method. Gene Set Enrichment Analysis (GSEA) was performed using TCGA data set. RESULTS: Reduced TFAP2B expression in EC was significantly associated with high grade (OR=2.2 for well, moderate vs. poor), stage (OR=2.5 for I vs. IV), histology (OR=1.8 for serous vs. endometrioid), distant metastasis (OR=2.4 for positive vs. negative) (all p-values<0.05). Kaplan-Meier survival analysis showed that EC with TFAP2B-low had a worse prognosis than that with TFAP2B-high (p=0.013). The univariate analysis revealed that TFAP2B-low correlated significantly with a poor overall survival (OS) (HR: 2.35; 95% confidence interval [CI]: 1.17-4.73; p=0.016). The multivariate analysis revealed that TFAP2B remained independently associated with overall survival, with a HR of 4.42 (CI: 1.25-12.64; p=0.021). GSEA show that p53/hypoxia pathway, androgen response, notch signaling, fatty acid metabolism, glycolysis and estrogen response late are differentially enriched in TFAP2B high expression phenotype. CONCLUSIONS: TFAP2B expression may be a potential prognostic molecular marker of poor survival in endometrial cancer, Moreover, the p53/hypoxia, androgen response and notch signaling pathway may be the key pathway regulated by TFAP2B in EC.

Tfap2b mutation in mice results in patent ductus arteriosus and renal malformation.

BACKGROUND: Transcription factor TFAP2B is associated with Char syndrome in humans and is characterized by patent ductus arteriosus (PDA) and facial and finger abnormalities. In a previous study, we detected a c.435_438delCCGG TFAP2B mutation in a family with PDA, and no facial dysmorphism or finger abnormalities were observed. This 4-base pair (bp) deletion in exon 2 resulted in a truncated protein of about 21 kDa in cultured cells in vitro. However, it is not clear why c.435_438delCCGG mutation carriers are present with isolated PDA instead of Char syndrome. MATERIALS AND METHODS: We successfully established a mouse model bearing Tfap2b c.435_438delCCGG mutation using CRISPR/Cas9 technology. The mutant mice were phenotyped using histological analysis, and the development of ductus smooth muscles in mutant mice was examined by immunohistochemistry. RESULTS: The c.435_438delCCGG homozygous mutant mice were characterized by delayed closure of the ductus arteriosus (DA) and renal malformation. Furthermore, the c.435_438delCCGG mutation might result in PDA by affecting the development of ductus arterious smooth muscle cells. CONCLUSIONS: Using the c.435_438delCCGG homozygous mice, we verified the nature of the c.435_438delCCGG mutation and established a new and useful animal model to explore the function of Tfap2b and the mechanisms of PDA and renal formation. These findings may be useful for the development of therapies for those rare disorder.

Characterization of transcription factor AP-2 ß mutations involved in familial isolated patent ductus arteriosus suggests haploinsufficiency.

BACKGROUND: Patent ductus arteriosus (PDA) is one of the most common congenital heart defects. Transcription factor AP-2 beta (TFAP2B) mutations are associated with the Char syndrome, a disorder associated with PDA, and with facial and fingers abnormalities. Recently, we identified two TFAP2B mutations in two families without Char syndrome phenotype, c.601+5G>A and c.435_438delCCGG, and these TFAP2B mutations were associated with familial isolated PDA. The aim of this study was to identify the effects of these mutations on TFAP2B function. METHODS: Plasmids containing the wild-type or mutated TFAP2B were constructed and transfected in cells. Plasmids containing the TFAP2B coactivator, Cpb/p300-interacting transactivator 2 (CITED2), was also transfected. TFAP2B expression was detected by luciferase expression and by Western blot analysis. RESULTS: These mutations resulted in loss of transactivation function, which could not be improved by Cpb/p300-interacting transactivator 2. The c.601+5G>A mutated gene did not express any protein, whereas the c.435_438delCCGG mutation did not impact the transactivation function activated by the wild-type TFAP2B. CONCLUSIONS: These results suggest that a haploinsufficiency effect of TFAP2B could be involved in familial isolated PDA.

Crucial role of TFAP2B in the nervous system for regulating NREM sleep.

The AP-2 transcription factors are crucial for regulating sleep in both vertebrate and invertebrate animals. In mice, loss of function of the transcription factor AP-2ß (TFAP2B) reduces non-rapid eye movement (NREM) sleep. When and where TFAP2B functions, however, is unclear. Here, we used the Cre-loxP system to generate mice in which Tfap2b was specifically deleted in the nervous system during development and mice in which neuronal Tfap2b was specifically deleted postnatally. Both types of mice exhibited reduced NREM sleep, but the nervous system-specific deletion of Tfap2b resulted in more severe sleep phenotypes accompanied by defective light entrainment of the circadian clock and stereotypic jumping behavior. These findings indicate that TFAP2B in postnatal neurons functions at least partly in sleep regulation and imply that TFAP2B also functions either at earlier stages or in additional cell types within the nervous system.

Novel Circular RNA CircUBAP2 Drives Tumor Progression by Regulating the miR-143/TFAP2B Axis in Prostate Cancer.

BACKGROUND: More and more investigations reveal that circular RNAs (circRNAs) are involved in cancer progression. CircRNA UBAP2 was closely related to prostate cancer. However, the biological function and specifical mechanism of circUBAP2 are still poorly discovered in prostate cancer (PCa). OBJECTIVES: This study aims to explore the biological function and mechanism of circUBAP2 in PCa. METHODS: The levels of mRNA and proteins were assessed by qRT-PCR assay and Western blot, respectively. Cell growth, migration, and invasion ability were measured using CCK-8 assay and Transwell assay. Apoptosis was assessed using flow cytometry. The interactions between circUBAP2, miR-143, and TFAP2B were determined by luciferase report assay. The tumor growth was determined by in vivo tumor formation assay. The tumor morphology was assessed using H&E staining assay, and immunohistochemistry assay was conducted to assess the level of KI67. RESULTS: We found circUBAP2 and TFAP2B were notably elevated, while miR-143 was largely attenuated in prostate cancer cells and tissues. CircUBAP2 was found to affect cell viability, metastasis and EMT, while attenuating the apoptosis rate of prostate cancer cells. CircUBAP2 directly targeted miR-143, and miR-143 inhibitor could reverse the effects that circUBAP2 interference-induced in prostate cancer cells. TFAP2B is directly bound to miR-143, and overexpression of TFAP2B could attenuate the influences that miR-143-induced in prostate cancer cells. CONCLUSION: CircUBAP2 promoted prostate cancer progression via miR-143/TFAP2B axis.

ATOH1, TFAP2B, and CEACAM6 as Immunohistochemical Markers to Distinguish Merkel Cell Carcinoma and Small Cell Lung Cancer.

Merkel cell carcinoma (MCC) and small cell lung cancer (SCLC) can be histologically similar. Immunohistochemistry (IHC) for cytokeratin 20 (CK20) and thyroid transcription factor 1 (TTF-1) are commonly used to differentiate MCC from SCLC; however, these markers have limited sensitivity and specificity. To identify new diagnostic markers, we performed differential gene expression analysis on transcriptome data from MCC and SCLC tumors. Candidate markers included atonal BHLH transcription factor 1 (ATOH1) and transcription factor AP-2ß (TFAP2B) for MCC, as well as carcinoembryonic antigen cell adhesion molecule 6 (CEACAM6) for SCLC. Immunostaining for CK20, TTF-1, and new candidate markers was performed on 43 MCC and 59 SCLC samples. All three MCC markers were sensitive and specific, with CK20 and ATOH1 staining 43/43 (100%) MCC and 0/59 (0%) SCLC cases and TFAP2B staining 40/43 (93%) MCC and 0/59 (0%) SCLC cases. TTF-1 stained 47/59 (80%) SCLC and 1/43 (2%) MCC cases. CEACAM6 stained 49/59 (83%) SCLC and 0/43 (0%) MCC cases. Combining CEACAM6 and TTF-1 increased SCLC detection sensitivity to 93% and specificity to 98%. These data suggest that ATOH1, TFAP2B, and CEACAM6 should be explored as markers to differentiate MCC and SCLC.

Transcription Factor TFAP2B Exerts Neuroprotective Effects Targeting BNIP3-Mediated Mitophagy in Ischemia/Reperfusion Injury.

Cerebral ischemia-reperfusion injury (CIRI) leads to malignant brain edema, blood-brain barrier destruction, and neuronal apoptosis. N6-methyladenosine (m6A) RNA modification in CIRI was still limited explored. In this study, MeRIP- and RNA-sequencing were performed of middle cerebral artery occlusion and reperfusion (MCAO/R) rats to find novel potential molecular targets. Transcription factor TFAP2B stood out of which its m6A abundance decreased associated with a marked reduction of its mRNA based on cojoint interactive bioinformatics analysis of the MeRIP- and RNA-sequencing data. It was suggested TFAP2B could have a role in CIRI. Functionally, overexpression of TFAP2B in cultured primary neurons could effectively improve the cell survival and pro-survival autophagy in parallel with reduced cell apoptosis during OGD/R in vitro. Through the RNA-sequencing of TFAP2B overexpressed primary neurons and subsequent validation experiments, it was found that mitophagy receptor BNIP3 was one of the important targets of TFAP2B in OGD/R neurons through which TFAP2B could bind to its promoter region for transcriptional activation of BNIP3, thereby enhancing BNIP3-mediated mitophagy to protect against OGD/R injury of neurons. Lastly, TFAP2B was demonstrated to alleviate the MCAO/R damage to a certain extent in vivo. Although it failed to confirm TFAP2B dysregulation was m6A dependent in current research, this is the first research of TFAP2B in CIRI field with important guiding significance.

ALDH1A3-acetaldehyde metabolism potentiates transcriptional heterogeneity in melanoma.

Cancer cellular heterogeneity and therapy resistance arise substantially from metabolic and transcriptional adaptations, but how these are interconnected is poorly understood. Here, we show that, in melanoma, the cancer stem cell marker aldehyde dehydrogenase 1A3 (ALDH1A3) forms an enzymatic partnership with acetyl-coenzyme A (CoA) synthetase 2 (ACSS2) in the nucleus to couple high glucose metabolic flux with acetyl-histone H3 modification of neural crest (NC) lineage and glucose metabolism genes. Importantly, we show that acetaldehyde is a metabolite source for acetyl-histone H3 modification in an ALDH1A3-dependent manner, providing a physiologic function for this highly volatile and toxic metabolite. In a zebrafish melanoma residual disease model, an ALDH1-high subpopulation emerges following BRAF inhibitor treatment, and targeting these with an ALDH1 suicide inhibitor, nifuroxazide, delays or prevents BRAF inhibitor drug-resistant relapse. Our work reveals that the ALDH1A3-ACSS2 couple directly coordinates nuclear acetaldehyde-acetyl-CoA metabolism with specific chromatin-based gene regulation and represents a potential therapeutic vulnerability in melanoma.

Transcription factor activating enhancer-binding protein 2B expression correlates with invasiveness and prognosis of extramammary Paget's disease.

BACKGROUND: Extramammary Paget's disease (EMPD) is a slowly advancing malignancy that sometimes progresses to the invasion of the dermis, systemic metastases, and death. Although there have been reports that dermal invasion is associated with poor prognosis, no molecular markers of this invasion have been identified thus far. The aim of this study was to identify key molecules for predicting the risk of EMPD dermis invasion. METHOD: We performed microarray screening for three cases of in-situ EMPDs, three cases of invasive EMPDs, and three cases of normal epidermis. We identified a molecule that exhibited a stepwise increase in expression. Further, we analyzed 47 cases of EMPD using immunohistochemical staining (IHC) and examined the correlated clinicopathological findings, including prognosis. RESULT: We examined molecules that showed stepwise differences with invasion. We focused on transcription factor activating enhancer-binding protein 2 B (TFAP2B). Of the 47 EMPD patients, 38 (80.9 %) and 9 (19.1 %) had low and high TFAP2B expression, respectively. TFAP2B expression was significantly correlated with invasion into the dermis, mass formation, and preoperative lymph node metastasis (p = 0.001, 0.042, and 0.033, respectively). The cumulative postoperative recurrence-free rate in the TFAP2B-high expression group was significantly lower than that in the TFAP2B-low expression group (P < 0.001). In univariate analysis of recurrence-free survival, TFAP2B expression was found to be a significant factor (p = 0.006). CONCLUSION: The expression of TFAP2B, which was comprehensively found by microarray screening, may correlate with the invasiveness of EMPD and may be an unfavorable prognostic factor.

Principles of Zebrafish Nephron Segment Development.

Nephrons are the functional units which comprise the kidney. Each nephron contains a number of physiologically unique populations of specialized epithelial cells that are organized into discrete domains known as segments. The principles of nephron segment development have been the subject of many studies in recent years. Understanding the mechanisms of nephrogenesis has enormous potential to expand our knowledge about the basis of congenital anomalies of the kidney and urinary tract (CAKUT), and to contribute to ongoing regenerative medicine efforts aimed at identifying renal repair mechanisms and generating replacement kidney tissue. The study of the zebrafish embryonic kidney, or pronephros, provides many opportunities to identify the genes and signaling pathways that control nephron segment development. Here, we describe recent advances of nephron segment patterning and differentiation in the zebrafish, with a focus on distal segment formation.

Transcription factor Ap2b regulates the mouse autosomal recessive polycystic kidney disease genes, Pkhd1 and Cys1.

Transcription factor Ap2b (TFAP2B), an AP-2 family transcription factor, binds to the palindromic consensus DNA sequence, 5'-GCCN3-5GGC-3'. Mice lacking functional Tfap2b gene die in the perinatal or neonatal period with cystic dilatation of the kidney distal tubules and collecting ducts, a phenotype resembling autosomal recessive polycystic kidney disease (ARPKD). Human ARPKD is caused by mutations in PKHD1, DZIP1L, and CYS1, which are conserved in mammals. In this study, we examined the potential role of TFAP2B as a common regulator of Pkhd1 and Cys1. We determined the transcription start site (TSS) of Cys1 using 5' Rapid Amplification of cDNA Ends (5'RACE); the TSS of Pkhd1 has been previously established. Bioinformatic approaches identified cis-regulatory elements, including two TFAP2B consensus binding sites, in the upstream regulatory regions of both Pkhd1 and Cys1. Based on reporter gene assays performed in mouse renal collecting duct cells (mIMCD-3), TFAP2B activated the Pkhd1 and Cys1 promoters and electromobility shift assay (EMSA) confirmed TFAP2B binding to the in silico identified sites. These results suggest that Tfap2b participates in a renal epithelial cell gene regulatory network that includes Pkhd1 and Cys1. Disruption of this network impairs renal tubular differentiation, causing ductal dilatation that is the hallmark of recessive PKD.

Tfap2b specifies an embryonic melanocyte stem cell that retains adult multifate potential.

Melanocytes, the pigment-producing cells, are replenished from multiple stem cell niches in adult tissue. Although pigmentation traits are known risk factors for melanoma, we know little about melanocyte stem cell (McSC) populations other than hair follicle McSCs and lack key lineage markers with which to identify McSCs and study their function. Here we find that Tfap2b and a select set of target genes specify an McSC population at the dorsal root ganglia in zebrafish. Functionally, Tfap2b is required for only a few late-stage embryonic melanocytes, and is essential for McSC-dependent melanocyte regeneration. Fate mapping data reveal that tfap2b+ McSCs have multifate potential, and are the cells of origin for large patches of adult melanocytes, two other pigment cell types (iridophores and xanthophores), and nerve-associated cells. Hence, Tfap2b confers McSC identity in early development, distinguishing McSCs from other neural crest and pigment cell lineages, and retains multifate potential in the adult zebrafish.

Integrative RNA profiling of TBEV-infected neurons and astrocytes reveals potential pathogenic effectors.

Tick-borne encephalitis virus (TBEV), the most medically relevant tick-transmitted flavivirus in Eurasia, targets the host central nervous system and frequently causes severe encephalitis. The severity of TBEV-induced neuropathogenesis is highly cell-type specific and the exact mechanism responsible for such differences has not been fully described yet. Thus, we performed a comprehensive analysis of alterations in host poly-(A)/miRNA/lncRNA expression upon TBEV infection in vitro in human primary neurons (high cytopathic effect) and astrocytes (low cytopathic effect). Infection with severe but not mild TBEV strain resulted in a high neuronal death rate. In comparison, infection with either of TBEV strains in human astrocytes did not. Differential expression and splicing analyses with an in silico prediction of miRNA/mRNA/lncRNA/vd-sRNA networks found significant changes in inflammatory and immune response pathways, nervous system development and regulation of mitosis in TBEV Hypr-infected neurons. Candidate mechanisms responsible for the aforementioned phenomena include specific regulation of host mRNA levels via differentially expressed miRNAs/lncRNAs or vd-sRNAs mimicking endogenous miRNAs and virus-driven modulation of host pre-mRNA splicing. We suggest that these factors are responsible for the observed differences in the virulence manifestation of both TBEV strains in different cell lines. This work brings the first complex overview of alterations in the transcriptome of human astrocytes and neurons during the infection by two TBEV strains of different virulence. The resulting data could serve as a starting point for further studies dealing with the mechanism of TBEV-host interactions and the related processes of TBEV pathogenesis.