Expression Of Zbtb20 Research Articles

Excess homocysteine inhibits pancreatic β-cell secretory function by repressing Zbtb20 expression

Homocysteine (Hcy) is a sulfur-containing amino acid. An elevated level of Hcy is a risk factor for diabetes development. However, the mechanism of its effect on pancreatic β-cell function is unclear. In this study, we constructed a hyperhomocysteinemia (HHcy) mouse model by feeding mice a high methionine diet (HMD). The mice suffered impaired glucose tolerance and reduced insulin secretion. Furthermore, at the cellular level, INS1 cells exhibited impaired insulin secretory function after the Hcy intervention. Transcriptomics revealed that Zbtb20 expression was downregulated and the downstream gene Fbp1 was upregulated in HHcy-induced mice compared with mice fed with normal diet. Insulin secretion could be restored by Zbtb20 overexpression or fructose 1,6-bisphosphatase (FBPase) activity inhibition in INS1 cells. In conclusion, our study suggested that Hcy inhibited the insulin secretory function of pancreatic β-cells by suppressing Zbtb20 expression, leading to the development of diabetes. Zbtb20 may be a key target in the development of diabetes associated with elevated Hcy levels.

ZBTB20 mediates stress-induced visceral hypersensitivity via activating the NF-κB/transient receptor potential channel pathway.

Psychological stress is a major trigger for visceral hypersensitivity (VH) in irritable bowel syndrome. The zinc finger protein ZBTB20 (ZBTB20) is implicated in somatic nociception via modulating transient receptor potential (TRP) channels, but its role in the development of VH is unclear. This study aimed to investigate the role of ZBTB20/TRP channel axis in stress-induced VH. Rats were subjected to water avoidance stress (WAS) for 10 consecutive days. Small interfering RNA (siRNA) targeting ZBTB20 was intrathecally administered. Inhibitors of TRP channels, stress hormone receptors, and nuclear factor kappa-B (NF-κB) were administered. Visceromotor response to colorectal distension was recorded. Dorsal root ganglia (DRGs) were dissected for Western blot, coimmunoprecipitation, and chromatin immunoprecipitation. The DRG-derived neuron cell line was applied for specific research. WAS-induced VH was suppressed by the inhibitor of TRPV1, TRPA1, or TRPM8, with enhanced expression of these channels in L6-S2 DRGs. The inhibitor of glucocorticoid receptor or β2-adrenergic receptor counteracted WAS-induced VH and TRP channel expression. Concurrently, WAS-induced stress hormone-dependent ZBTB20 expression and NF-κB activation in DRGs. Intrathecally injected ZBTB20 siRNA or an NF-κB inhibitor repressed WAS-caused effect. In cultured DRG-derived neurons, stress hormones promoted nuclear translocation of ZBTB20, which preceded p65 nuclear translocation. And, ZBTB20 siRNA suppressed stress hormone-caused NF-κB activation. Finally, WAS enhanced p65 binding to the promoter of TRPV1, TRPA1, or TRPM8 in rat DRGs. ZBTB20 mediates stress-induced VH via activating NF-κB/TRP channel pathway in nociceptive sensory neurons.

RNA-Seq transcriptome analysis of renal tissue from spontaneously hypertensive rats revealed renal protective effects of dapagliflozin, an inhibitor of sodium-glucose cotransporter 2

Hypertensive nephropathy (HTN) is a common complication of hypertension. Although various agents for treatment of hypertension exert significant effects, there is currently no effective treatment for hypertensive nephropathy. Sodium-glucose cotransporter 2 (SGLT2) inhibitors, such as dapagliflozin (DAPA), are a new class of hypoglycemic agents shown to improve the prognosis of patients with chronic kidney disease and diabetes mellitus. However, the mechanisms underlying the protective effects of DAPA remain unclear. RNA-sequencing (RNA-Seq)-based computational analysis was conducted to explore the transcriptomic changes to spontaneously hypertensive rats (SHRs) treated with DAPA for 8 weeks. Differentially expressed genes in SHRs were related to dysregulation of lipid metabolism, oxidation–reduction reaction, immunity and inflammation in HTN. Transcriptome analysis showed that 8 weeks of DAPA therapy exerted protective effects on the renal tissues of SHRs through the lysosomal, phagosomal, and autophagic pathways. VENN diagram analysis identified Zinc finger and BTB domain-containing 20 (Zbtb20) as the potential target of DAPA therapy. Consistent with the RNA-Seq findings, real-time quantitative PCR and immunohistochemical analyses revealed increased expression of Zbtb20 in the renal tissues of SHRs, whereas expression was decreased following 8 weeks of DAPA administration. The results of this study clarified the transcriptome signature of HTN and the beneficial effects of DAPA on renal tissues by alleviating dysregulation of metabolic processes and reducing inflammation.

Ginsenoside Rb3 reduces ox-LDL-induced injury in human aortic endothelial cells by regulating the miR-513a-5p/ZBTB20 axis.

Atherosclerosis (AS) is a common vascular disease, and its main influencing factor is endothelial damage caused by oxidized low-density lipoprotein (ox-LDL). As one of the main active ingredients of ginseng, ginsenoside Rb3 has anti-inflammatory and anti-oxidative effects. However, the role of ginsenoside Rb3 in endothelial injury induced by ox-LDL is not clear. This study aimed to evaluate the effect and potential mechanism of ginsenoside Rb3 action on ox-LDL-treated human aortic endothelial cells (HAECs). The HAECs treated with ox-LDL were used to establish an in vitro AS model. The viability of the HAECs was analyzed with Cell Counting Kit-8 (CCK-8). Flow cytometry was performed to assess the apoptosis. Oxidative stress, inflammation and endothelial dysfunction were evaluated using enzyme-linked immunosorbent assay (ELISA) and western blotting. The levels of miR-513a-5p were assessed using quantitative real-time polymerase chain reaction (qPCR). A dual-luciferase assay was performed to analyze the relationship between miR-513a-5p and a zinc finger and BTB domain-containing protein (ZBTB20). Exposure of HAECs to ox-LDL (50 μg/mL) reduced cell viability, superoxide dismutase (SOD) activity and endothelial nitric oxide synthase (eNOS) expression, while increasing the levels of malondialdehyde (MDA), interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α), and soluble intercellular adhesion molecule-1 (sICAM-1). The pretreatment with Rb3 markedly enhanced cell viability and decreased ox-LDL-induced oxidative stress, inflammation and endothelial dysfunction in HAECs. The ox-LDL decreased the level of miR-513a-5p, which was reversed by Rb3 pretreatment. The ZBTB20 was a target of miR-513a-5p in HAECs, and ox-LDL upregulated ZBTB20 expression, which was reversed by Rb3 pretreatment. The protective effect of Rb3 on ox-LDL-induced HAECs was diminished by miR-513a-5p inhibition, which was reversed by ZBTB20 knockdown. Ginsenoside Rb3 reduces the effects of ox-LDL on HAECs by regulating the miR-513a-5p/ZBTB20 axis, which provides a theoretical basis for the treatment of AS.

The long non-coding RNA KLF3-AS1/miR-10a-3p/ZBTB20 axis improves the degenerative changes in human nucleus pulposus cells.

Excessive apoptosis of intervertebral disc cells, namely nucleus pulposus (NP) cells, results in decreased cell density and extracellular matrix (ECM) catabolism, hence leading to intervertebral disc degeneration (IVDD). As a cell model in the present study, a commercially available human NP cell line was utilized. Long noncoding RNAs and microRNAs may regulate the proliferation or apoptosis of human NP cells, hence exerting a significant influence on the occurrence of IVDD. KLF3-AS1 was discovered to be abnormally downregulated in IVDD tissues. Overexpression of KLF3-AS1 enhanced NP cell viability, prevented cell apoptosis, boosted ECM synthesis, and lowered MMP-13 and ADAMTS4 levels. ZBTB20 and KLF3-AS1 were co-expressed in IVDD; ZBTB20 overexpression had similar effects on NP cells, ECM production, and MMP-13 and ADAMTS4 levels as KLF3-AS1 overexpression. miR-10a-3p may target KLF3-AS1 and ZBTB20 and inhibit the expression of ZBTB20. Inhibition of miR-10a-3p enhanced NP cell viability, reduced apoptosis, and enhanced ECM synthesis. KLF3-AS1 overexpression increased ZBTB20 expression, whereas miR-10a-3p overexpression decreased ZBTB20 expression; miR-10a-3p overexpression reduced the effects of KLF3-AS1 on ZBTB20. Overexpression of miR-10a-3p consistently decreased the effects of KLF3-AS1 overexpression on NP cell survival, apoptosis, and ECM synthesis. In conclusion, KLF3-AS1 overexpression may ameliorate degenerative NP cell alterations through the miR-10a-3p/ZBTB20 axis.

ZBTB20-AS1 promoted Alzheimer's disease progression through ZBTB20/GSK-3β/Tau pathway

To elucidate the potential molecular mechanisms of ZBTB20-AS1 on ZBTB20 and GSK-3β/Tau signaling pathway in the pathogenesis of Alzheimer's disease (AD), SH-SY5Y cells were obtained for in vitro experiments and AD models were constructed using β-Amyloid 1–42. CCK8 assay was implemented for determining cell viability. Flow cytometry was used for cell apoptosis detection. Dual-luciferase reporter and RNA-RNA pull down assay was employed for elucidating molecular interactions. Immunohistochemistry, RT-qPCR and western blotting were performed for measuring gene expression. The results showed that expression of LncRNA ZBTB20-AS1 was significantly upregulated, while ZBTB20 was downregulated in SH-SY5Y-AD cells. ZBTB20 was the target gene of LncRNA ZBTB20-AS1. Overexpression of ZBTB20 or knockdown of LncRNA ZBTB20-AS1 inhibited SH-SY5Y-AD cells apoptosis and suppressed GSK3β/Tau pathway, and knockdown of ZBTB20-AS1 increased cell viability and decreased apoptosis. In conclusion, overexpression of ZBTB20-AS1 inhibited ZBTB20 expression and promoted GSK-3β expression and Tau phosphorylation, contributing to the development of AD.

Dysfunctional microRNA-144-3p/ZBTB20/ERK/CREB1 signalling pathway is associated with MK-801-induced schizophrenia-like abnormalities

Schizophrenia is a group of severe mental disorders. ZBTB20 is critical in brain development and corticogenesis and its dysfunction induces various neural disorders. ERK/CREB signalling is a potential downstream pathway of ZBTB20. Up-regulated microRNA-144-3p (miR-144-3p) were found in schizophrenic model rats in our previous study. This study investigated whether suppressed ZBTB20/ERK/CREB1 signalling caused by up-regulated miR-144-3p is associated with schizophrenia-like abnormalities in animals. A MK-801 rat model was established by 2-week MK-801 administration. An RNA-Seq test was performed to reveal differentially expressed genes in model rat hippocampus (HIP). MiR-144-3p-overexpressed SK-N-SH and 293T cell models were constructed by lentivirus, respectively. The in vitro and in vivo levels of miR-144-3p and ZBTB20, and the activation of the ERK/CREB1 signalling were examined by qRT-PCR, Western blots, or immunohistochemistry. The interaction between miR-144-3p and ZBTB20 was predicted and assessed by using bioinformatic methods and a luciferase reporter gene assay on 293T cells, respectively. The RNA-Seq test revealed that ZBTB20 was altered in the model rat HIP. Further experiments confirmed the reduced ZBTB20 mRNA and protein levels in the model rat HIP and caudate putamen (CPu), accompanied by increased miR-144-3p levels. Moreover, the ZBTB20 expression and ERK/CREB1 phosphorylation was decreased in the miR-144-3p-overexpressed 293T cells. These abnormal changes in the ZBTB20 expression and ERK/CREB1 phosphorylation levels were also observed in the model rat brain, but could be reversed by risperidone. In conclusion, this study revealed that dysfunctional miR-144-3p/ZBTB20/ERK/CREB1 signalling might be associated with schizophrenia-like abnormalities, suggesting potential therapeutic targets for future schizophrenia treatment.

Expression of Transcription Factor ZBTB20 in the Adult Primate Neurogenic Niche under Physiological Conditions or after Ischemia.

The Zbtb20 gene encodes for a transcription factor that plays an important role in mammalian cortical development. Recently, its expression was reported in the adult mouse subventricular zone (SVZ), a major neurogenic niche containing neural stem cells throughout life. Here, we analyzed its expression in the adult primate anterior SVZ (SVZa) and rostral migratory stream (RMS) using macaque monkeys (Macaca fuscata). We report that the majority of Ki67+ cells, 71.4% in the SVZa and 85.7% in the RMS, co-label for ZBTB20. Nearly all neuroblasts, identified by their Doublecortin expression, were positive for ZBTB20 in both regions. Nearly all GFAP+ neural stem cells/astrocytes were also positive for ZBTB20. Analysis of images derived from a public database of gene expression in control/ischemic monkey SVZa, showed evidence for ZBTB20 upregulation in postischemic monkey SVZa. Furthermore, the co-localization of ZBTB20 with Doublecortin and Ki67 was increased in the postischemic SVZa. Our results suggest that ZBTB20 expression is evolutionarily conserved in the mammalian neurogenic niche and is reactive to ischemia. This opens the possibility for further functional studies on the role of this transcription factor in neurogenesis in primates.

Zbtb20 identifies and controls a thymus-derived population of regulatory T cells that play a role in intestinal homeostasis.

The expression of BTB-ZF transcription factors such as ThPOK in CD4+ T cells, Bcl6 in T follicular helper cells, and PLZF in natural killer T cells defines the fundamental nature and characteristics of these cells. Screening for lineage-defining BTB-ZF genes led to the discovery of a subset of T cells that expressed Zbtb20. About half of Zbtb20+ T cells expressed FoxP3, the lineage-defining transcription factor for regulatory T cells (Tregs). Zbtb20+ Tregs were phenotypically and genetically distinct from the larger conventional Treg population. Zbtb20+ Tregs constitutively expressed mRNA for interleukin-10 and produced high levels of the cytokine upon primary activation. Zbtb20+ Tregs were enriched in the intestine and specifically expanded when inflammation was induced by the use of dextran sodium sulfate. Conditional deletion of Zbtb20 in T cells resulted in a loss of intestinal epithelial barrier integrity. Consequently, knockout (KO) mice were acutely sensitive to colitis and often died because of the disease. Adoptive transfer of Zbtb20+ Tregs protected the Zbtb20 conditional KO mice from severe colitis and death, whereas non-Zbtb20 Tregs did not. Zbtb20 was detected in CD24hi double-positive and CD62Llo CD4 single-positive thymocytes, suggesting that expression of the transcription factor and the phenotype of these cells were induced during thymic development. However, Zbtb20 expression was not induced in "conventional" Tregs by activation in vitro or in vivo. Thus, Zbtb20 expression identified and controlled the function of a distinct subset of Tregs that are involved in intestinal homeostasis.

An epigenetic circuit controls neurogenic programs during neocortex development.

The production and expansion of intermediate progenitors (IPs) are essential for neocortical neurogenesis during development and over evolution. Here, we have characterized an epigenetic circuit that precisely controls neurogenic programs, particularly properties of IPs, during neocortical development. The circuit comprises a long non-coding RNA (LncBAR) and the BAF (SWI/SNF) chromatin-remodeling complex, which transcriptionally maintains the expression of Zbtb20. LncBAR knockout neocortex contains more deep-layer but fewer upper-layer projection neurons. Intriguingly, loss of LncBAR promotes IP production, but paradoxically prolongs the duration of the cell cycle of IPs during mid-later neocortical neurogenesis. Moreover, in LncBAR knockout mice, depletion of the neural progenitor pool at embryonic stage results in fewer adult neural progenitor cells in the subventricular zone of lateral ventricles, leading to a failure in adult neurogenesis to replenish the olfactory bulb. LncBAR binds to BRG1, the core enzymatic component of the BAF chromatin-remodeling complex. LncBAR depletion enhances association of BRG1 with the genomic locus of, and suppresses the expression of, Zbtb20, a transcription factor gene known to regulate both embryonic and adult neurogenesis. ZBTB20 overexpression in LncBAR-knockout neural precursors reverses compromised cell cycle progressions of IPs.

Phenotypic Differences between the Alzheimer's Disease-Related hAPP-J20 Model and Heterozygous Zbtb20 Knock-Out Mice.

Diverse gene products contribute to the pathogenesis of Alzheimer’s disease (AD). Experimental models have helped elucidate their mechanisms and impact on brain functions. Human amyloid precursor protein (hAPP) transgenic mice from line J20 (hAPP-J20 mice) are widely used to simulate key aspects of AD. However, they also carry an insertional mutation in noncoding sequence of one Zbtb20 allele, a gene involved in neural development. We demonstrate that heterozygous hAPP-J20 mice have reduced Zbtb20 expression in some AD-relevant brain regions, but not others, and that Zbtb20 levels are higher in hAPP-J20 mice than heterozygous Zbtb20 knock-out (Zbtb20+/–) mice. Whereas hAPP-J20 mice have premature mortality, severe deficits in learning and memory, other behavioral alterations, and prominent nonconvulsive epileptiform activity, Zbtb20+/– mice do not. Thus, the insertional mutation in hAPP-J20 mice does not ablate the affected Zbtb20 allele and is unlikely to account for the AD-like phenotype of this model.

HBx increases EGFR expression by inhibiting miR129–5p function

Despite the efficient suppression of hepatitis B virus (HBV) replication by nucelos(t)ide analogs, HBV RNA expression usually continues even during nucleots(t)ide analog therapy because episomal covalently closed circular DNA (ccDNA), which is the template for HBV RNA transcription, cannot be eliminated. Here, we found that the common sequences of all HBV RNAs and that encoding the X protein (HBx) have similarities with the sequences of a host cellular microRNA (miRNA), miR129–5p. HBx inhibits miR129–5p function, resulting in increased expression of ZBTB20, a target gene of miR129–5p. ZBTB20 activates transcription and increases cell-surface epidermal growth factor receptor (EGFR) levels, promoting the cell growth rate, and this effect was reversed through ZBTB20 knockdown. mir129–5p levels in Ago2-containing complexes were reduced by expression of HBx, suggesting that the viral RNA sequestered miR129–5p from Ago2-containing complexes. These results indicate the possibility that HBV RNA may maintain pathogenicity even through nucleos(t)ide analog therapy.

SUMOylation controls the neurodevelopmental function of the transcription factor Zbtb20.

SUMOylation is a dynamic post-translational protein modification that primarily takes place in cell nuclei, where it plays a key role in multiple DNA-related processes. In neurons, the SUMOylation-dependent control of a subset of neuronal transcription factors is known to regulate various aspects of nerve cell differentiation, development, and function. In an unbiased screen for endogenous SUMOylation targets in the developing mouse brain, based on a His6 -HA-SUMO1 knock-in mouse line, we previously identified the transcription factor Zinc finger and BTB domain-containing 20 (Zbtb20) as a new SUMO1-conjugate. We show here that the three key SUMO paralogues SUMO1, SUMO2, and SUMO3 can all be conjugated to Zbtb20 in vitro in HEK293FT cells, and we confirm the SUMOylation of Zbtb20 in vivo in mouse brain. Using primary hippocampal neurons from wild-type and Zbtb20 knock-out (KO) mice as a model system, we then demonstrate that the expression of Zbtb20 is required for proper nerve cell development and neurite growth and branching. Furthermore, we show that the SUMOylation of Zbtb20 is essential for its function in this context, and provide evidence indicating that SUMOylation affects the Zbtb20-dependent transcriptional profile of neurons. Our data highlight the role of SUMOylation in the regulation of neuronal transcription factors that determine nerve cell development, and they demonstrate that key functions of the transcription factor Zbtb20 in neuronal development and neurite growth are under obligatory SUMOylation control.

Effect of hepatitis B virus X gene integration on expression of zinc finger protein ZBTB20 in chronic hepatitis B patients complicated with hepatocellular carcinoma

Objective To investigate the effect of hepatitis B virus (HBV) X gene integration on expression of zinc finger protein ZBTB20 in chronic hepatitis B (CHB) patients complicated with hepatocellular carcinoma (HCC). Methods Eighteen CHB patients complicated with HCC who underwent surgical treatment in Taizhou Enze Medical Center Enze Hospital and Taizhou Central Hospital from July 2015 to June 2017 were enrolled. Samples of carcinoma tissue, para-carcinoma tissue and corresponding normal liver tissue were collected from each case. DNA was extracted from three kinds of tissue samples. HBV-Alu-polymerase chain reaction (PCR) was used to amplify the integrated HBVX fragments and their bilateral flanking sequences in human genomic DNA. The integrated HBV fragments were determined by PCR products sequencing. Protein was extracted from three kinds of tissue samples.The level of expression of ZBTB20 was detected by protein imprinting. Statistical analysis was performed using t test, analysis of variance, and χ2 test. Results Among the 18 CHB patients complicated with HCC, integration of HBVX gene was found in 13 carcinoma tissue samples, 16 para-carcinoma tissue samples and 9 corresponding normal liver tissue samples. The difference was statistically significant (χ2=6.353, P=0.037). Of the 18 patients, the protein expressions of ZBTB20 in carcinoma tissue, para-carcinoma tissue and corresponding normal tissue were (50.14±11.25)%, (40.71±7.17)% and (39.06±5.17)%, respectively, which was statistically different (F=9.420, P<0.01). HBVX gene integration was detected at ZBTB20 locus in five patients. The expression levels of ZBTB20 in patients with HBVX gene integration at this locus in carcinoma tissue, para-carcinoma tissue and corresponding, normal liver tissue were all significantly lower than those in patients without HBVX gene integration (carcinoma tissue (37.37±10.30)% vs (55.06±7.06)%, para-carcinoma tissue (32.06±2.61)% vs (44.04±5.24)%, corresponding normal tissue (34.66±5.59)% vs (40.76±4.04)%, t=4.205, 4.821 and 2.589, respectively, all P<0.05). Conclusions Incidence of HBVX integration in para-carcinoma tissue is higher than that in carcinoma tissue in CHB patients complicated with HCC.The expression level of ZBTB20 in carcinoma tissue is higher than that in para-carcinoma tissue. Integration of HBVX gene at ZBTB20 locus may decreases the expression of ZBTB20. Key words: Hepatitis B virus; Carcinoma, hepatocellular; Gene integration; Zinc finger protein ZBTB20

The integration site of the APP transgene in the J20 mouse model of Alzheimer's disease.

Background: Transgenic animal models are a widely used and powerful tool to investigate human disease and develop therapeutic interventions. Making a transgenic mouse involves random integration of exogenous DNA into the host genome that can have the effect of disrupting endogenous gene expression. The J20 mouse model of Alzheimer's disease (AD) is a transgenic overexpresser of human APP with familial AD mutations and has been extensively utilised in preclinical studies and our aim was to determine the genomic location of the J20 transgene insertion. Methods: We used a combination of breeding strategy and Targeted Locus Amplification with deep sequencing to identify the insertion site of the J20 transgene array. To assess RNA and protein expression of Zbtb20, we used qRT-PCR and Western Blotting. Results: We demonstrate that the J20 transgene construct has inserted within the genetic locus of endogenous mouse gene Zbtb20 on chromosome 16 in an array , disrupting expression of mRNA from this gene in adult hippocampal tissue. Preliminary data suggests that ZBTB20 protein levels remain unchanged in this tissue, however further study is necessary. We note that the endogenous mouse App gene also lies on chromosome 16, although 42 Mb from the Zbtb20 locus. Conclusions: These data will be useful for future studies utilising this popular model of AD, particularly those investigating gene interactions between the J20 APP transgene and other genes present on Mmu16 in the mouse.

The integration site of the APP transgene in the J20 mouse model of Alzheimer’s disease

Background: Transgenic animal models are a widely used and powerful tool to investigate human disease and develop therapeutic interventions. Making a transgenic mouse involves random integration of exogenous DNA into the host genome that can have the effect of disrupting endogenous gene expression. The J20 mouse model of Alzheimer’s disease (AD) is a transgenic overexpresser of human APP with familial AD mutations and has been extensively utilised in preclinical studies and our aim was to determine the genomic location of the J20 transgene insertion. Methods: We used a combination of breeding strategy and Targeted Locus Amplification with deep sequencing to identify the insertion site of the J20 transgene array. To assess RNA and protein expression of Zbtb20, we used qRT-PCR and Western Blotting. Results: We demonstrate that the J20 transgene construct has inserted within the genetic locus of endogenous mouse gene Zbtb20 on chromosome 16 in an array , disrupting expression of mRNA from this gene in adult hippocampal tissue. Preliminary data suggests that ZBTB20 protein levels remain unchanged in this tissue, however further study is necessary. We note that the endogenous mouse App gene also lies on chromosome 16, although 42 Mb from the Zbtb20 locus. Conclusions: These data will be useful for future studies utilising this popular model of AD, particularly those investigating gene interactions between the J20 APP transgene and other genes present on Mmu16 in the mouse.

Genome-wide association study of seasonal affective disorder

Family and twin studies have shown a genetic component to seasonal affective disorder (SAD). A number of candidate gene studies have examined the role of variations within biologically relevant genes in SAD susceptibility, but few genome-wide association studies (GWAS) have been performed to date. The authors aimed to identify genetic risk variants for SAD through GWAS. The authors performed a GWAS for SAD in 1380 cases and 2937 controls of European-American (EA) origin, selected from samples for GWAS of major depressive disorder and of bipolar disorder. Further bioinformatic analyses were conducted to examine additional genomic and biological evidence associated with the top GWAS signals. No susceptibility loci for SAD were identified at a genome-wide significant level. The strongest association was at an intronic variant (rs139459337) within ZBTB20 (odds ratio (OR) = 1.63, p = 8.4 × 10−7), which encodes a transcriptional repressor that has roles in neurogenesis and in adult brain. Expression quantitative trait loci (eQTL) analysis showed that the risk allele “T” of rs139459337 is associated with reduced mRNA expression of ZBTB20 in human temporal cortex (p = 0.028). Zbtb20 is required for normal murine circadian rhythm and for entrainment to a shortened day. Of the 330 human orthologs of murine genes directly repressed by Zbtb20, there were 32 associated with SAD in our sample (at p < 0.05), representing a significant enrichment of ZBTB20 targets among our SAD genetic association signals (fold = 1.93, p = 0.001). ZBTB20 is a candidate susceptibility gene for SAD, based on a convergence of genetic, genomic, and biological evidence. Further studies are necessary to confirm its role in SAD.

Zbtb20 Regulates Developmental Neurogenesis in the Olfactory Bulb and Gliogenesis After Adult Brain Injury.

The transcription factor (TF) Zbtb20 is important for the hippocampal specification and the regulation of neurogenesis of neocortical projection neurons. Herein, we show a critical involvement of theTF Zbtb20 in the neurogenesis of both projection neurons and interneurons of the olfactory bulb during embryonic stages. Our data indicate that the lack of Zbtb20 significantly diminishes the generation of a set of early-born Tbr2+ neurons during embryogenesis. Furthermore, we provide evidence that Zbtb20 regulates the transition between neurogenesis to gliogenesis in cortical radial glial progenitor cells at the perinatal (E18.5) stage. In the adult mammalian brain, Zbtb20 is expressed by GFAP+ neural progenitor cells (NPCs) located in the forebrain neurogenic niche, i.e.,the subventricular zone (SVZ) of the lateral ventricles. Upon induction of cerebral ischemia, we found that Zbtb20 expression is upregulated in astrocytic-like cells, whereas diminishing the expression levels of Zbtb20 significantly reduces the ischemia-induced astrocytic reaction as observed in heterozygous Zbtb20 loss-of-function mice. Altogether, these results highlight the important role of the TF Zbtb20 as a temporal regulator of neurogenesis or gliogenesis, depending on the developmental context.

The integration site of the APP transgene in the J20 mouse model of Alzheimer’s disease

Background: Transgenic animal models are a widely used and powerful tool to investigate human disease and develop therapeutic interventions. Making a transgenic mouse involves random integration of exogenous DNA into the host genome that can have the effect of disrupting endogenous gene expression. The J20 mouse model of Alzheimer's disease (AD) is a transgenic overexpresser of human APP with familial AD mutations and has been extensively utilised in preclinical studies and our aim was to determine the genomic location of the J20 transgene insertion. Methods: We used a combination of breeding strategy and Targeted Locus Amplification with deep sequencing to identify the insertion site of the J20 transgene array. To assess RNA and protein expression of Zbtb20, we used qRT-PCR and Western Blotting. Results: We demonstrate that the J20 transgene construct has inserted within the genetic locus of endogenous mouse gene Zbtb20 on chromosome 16 in an array , disrupting expression of mRNA from this gene in adult hippocampal tissue. Preliminary data suggests that ZBTB20 protein levels remain unchanged in this tissue, however further study is necessary. We note that the endogenous mouse App gene also lies on chromosome 16, although 42 Mb from the Zbtb20 locus. Conclusions: These data will be useful for future studies utilising this popular model of AD, particularly those investigating gene interactions between the J20 APP transgene and other genes present on Mmu16 in the mouse.

Zbtb20 modulates the sequential generation of neuronal layers in developing cortex.

BackgroundDuring corticogenesis, genetic programs encoded in progenitor cells at different developmental stages and inherited in postmitotic neurons specify distinct layer and area identities. Transcription factor Zbtb20 has been shown to play a role for hippocampal development but whether it is implicated in mammalian neocortical morphogenesis remains unknown.ResultsHere, we report that during embyogenesis transcription factor Zbtb20 has a dynamic spatio-temporal expression pattern in mitotic cortical progenitors through which it modulates the sequential generation of cortical neuronal layer identities. Zbtb20 knock out mice exhibited enhanced populations of early born L6-L4 neuronal subtypes and a dramatic reduction of the late born L3/L2 neurons. This defect was due to a temporal misbalance in the production of earlier versus later born neurons, leading to a progressive diminishing of the progenitor pool for the generation of L3-L2 neurons. Zbtb20 implements these temporal effects in part by binding to promoter of the orphan nuclear receptor CoupTF1/Nr2f1. In addition to its effects exerted in cortical progenitors, the postmitotic expression of Zbtb20 in L3/L2 neurons starting at birth may contribute to their proper differentiation and migration.ConclusionsOur findings reveal Zbtb20 as a novel temporal regulator for the generation of layer-specific neuronal identities.Electronic supplementary materialThe online version of this article (doi:10.1186/s13041-016-0242-2) contains supplementary material, which is available to authorized users.