BACKGROUND: Recently, a number of patients have been described with structural rearrangements at 3q13.31, delineating a novel microdeletion syndrome with common clinical features including developmental delay and other neurodevelopmental disorders (NDD). A smallest region of overlapping deletions (S
RO) involved five RefSeq genes, including the transcription factor gene ZBTB20 and the dopamine receptor gene DRD3, considered as candidate genes for the syndrome. METHODS AND RESULTS: We used array comparative genomic hybridization and next-generation mate-pair sequencing to identify key structural rearrangements involving ZBTB20 in two patients with NDD. In a patient with developmental delay, attention-deficit hyperactivity disorder, psychosis, Tourette's syndrome and autistic traits, a de novo balanced t(3;18) translocation truncated ZBTB20. The other breakpoint did not disrupt any gene. In a second patient with developmental delay and autism, we detected the first microdeletion at 3q13.31, which truncated ZBTB20 but did not involve DRD3 or the other genes within the previously defined SRO. Zbtb20 directly represses 346 genes in the developing murine brain. Of the 342 human orthologous ZBTB20 candidate target genes, we found 68 associated with NDD. Using chromatin immunoprecipitation and quantitative PCR, we validated the in vivo binding of Zbtb20 in evolutionary conserved regions in six of these genes (Cntn4, Gad1, Nrxn1, Nrxn3, Scn2a, Snap25). CONCLUSIONS: Our study links dosage imbalance of ZBTB20 to a range of neurodevelopmental, cognitive and psychiatric disorders, likely mediated by dysregulation of multiple ZBTB20 target genes, and provides new knowledge on the genetic background of the NDD seen in the 3q13.31 microdeletion syndrome.
Juven A, etal., Eur J Hum Genet. 2020 Aug;28(8):1044-1055. doi: 10.1038/s41431-020-0582-3. Epub 2020 Feb 18.
Primrose syndrome is characterized by variable intellectual deficiency, behavior disorders, facial features with macrocephaly, and a progressive phenotype with hearing loss and ectopic calcifications, distal muscle wasting, and contractures. In 2014, ZBTB20 vari
ants were identified as responsible for this syndrome. Indeed, ZBTB20 plays an important role in cognition, memory, learning processes, and has a transcription repressive effect on numerous genes. A more severe phenotype was discussed in patients with missense single nucleotide variants than in those with large deletions. Here, we report on the clinical and molecular results of 14 patients: 6 carrying ZBTB20 missense SNVs, 1 carrying an early truncating indel, and 7 carrying 3q13.31 deletions, recruited through the AnDDI-Rares network. We compared their phenotypes and reviewed the data of the literature, in order to establish more powerful phenotype-genotype correlations. All 57 patients presented mild-to-severe ID and/or a psychomotor delay. Facial features were similar with macrocephaly, prominent forehead, downslanting palpebral fissures, ptosis, and large ears. Hearing loss was far more frequent in patients with missense SNVs (p = 0.002), ectopic calcification, progressive muscular wasting, and contractures were observed only in patients with missense SNVs (p nonsignificant). Corpus callosum dysgenesis (p = 0.00004), hypothyroidism (p = 0.047), and diabetes were also more frequent in this group. However, the median age was 9.4 years in patients with deletions and truncating variant compared with 15.1 years in those with missense SNVs. Longer follow-up will be necessary to determine whether the phenotype of patients with deletions is also progressive.
Primrose syndrome and 3q13.31 microdeletion syndrome are clinically related disorders characterized by tall stature, macrocephaly, intellectual disability, disturbed behavior and unusual facial features, with diabetes, deafness, progressive muscle wasting and ectopic calcifications specifically occu
rring in the former. We report that missense mutations in ZBTB20, residing within the 3q13.31 microdeletion syndrome critical region, underlie Primrose syndrome. This finding establishes a genetic link between these disorders and delineates the impact of ZBTB20 dysregulation on development, growth and metabolism.
Nagao M, etal., Nat Commun. 2016 Mar 22;7:11102. doi: 10.1038/ncomms11102.
Multipotent neural precursor cells (NPCs) generate astrocytes at late stages of mammalian neocortical development. Many signalling pathways that regulate astrocytogenesis directly induce the expression of GFAP, a marker of terminally differentiated astrocytes. However, astrocyte specification occurs
before GFAP expression and essential factors for the specification step have remained elusive. Here we show that Zbtb20 regulates astrocyte specification in the mouse neocortex. Zbtb20 is highly expressed in late-stage NPCs and their astrocytic progeny. Overexpression and knockdown of Zbtb20 promote and suppress astrocytogenesis, respectively, although Zbtb20 does not directly activate the Gfap promoter. Astrocyte induction by Zbtb20 is suppressed by knockdown of Sox9 or NFIA. Furthermore, in the astrocyte lineage, Zbtb20 directly represses the expression of Brn2, which encodes a protein necessary for upper-layer neuron specification. Zbtb20 is thus a key determinant of astrocytogenesis, in which it collaborates with Sox9 and NFIA, and acts in part through direct repression of Brn2 expression.
Dong Q, etal., Genet Mol Res. 2015 Dec 21;14(4):17622-9. doi: 10.4238/2015.December.21.35.
Pituitary, a critical component in the neuroendocrine system, plays an indispensable role in the regulation of body growth. The transcriptional factor ZBTB20 is widely expressed in brain tissues and participates in hippocampal development; however, the detailed
molecular mechanism remains unknown. Therefore, the aim of this study was to investigate the effect of ZBTB20 on mouse pituitary development and related mechanisms in ZBTB20 gene knockout mice. The expressional profiles of ZBTB20 in various neuroendocrinal cells during the different developmental stages (from E10 to P0) were described by immunofluorescence staining. A ZBTB20 gene knockout mouse model was then generated. Real-time polymerase chain reaction and western blotting assays were used to detect the levels of five hormones: growth hormone (GH), prolactin (PRL), luteinizing hormone (LH), follicle-stimulating hormone (FSH), and thyroid-stimulating hormone (TSH). ZBTB20 protein expression was identified from E14 until birth. A majority of the pituitary endocrinal cells were ZBTB20-positive. In ZBTB20 knockout mice, the level of GH decreased by half and PRL expression was eliminated. No significant change was observed in the other three hormones (LH, FSH, and TSH). ZBTB20, an important transcriptional factor in pituitary development, is mainly responsible for the terminal differentiation of prolactin-secreting cells, thereby regulating the secretion of the pituitary hormones.
Alpha-fetoprotein (AFP) represents a classical model system to study developmental gene regulation in mammalian cells. We previously reported that liver ZBTB20 is developmentally regulated and plays a central role in AFP postnatal repression. Here we show that <
span style='font-weight:700;'>ZBTB20 is a sequence-specific transcriptional repressor of AFP. By ELISA-based DNA-protein binding assay and conventional gel shift assay, we successfully identified a ZBTB20-binding site at -104/-86 of mouse AFP gene, flanked by two HNF1 sites and two C/EBP sites in the proximal promoter. Importantly, mutation of the core sequence in this site fully abolished its binding to ZBTB20 in vitro, as well as the repression of AFP promoter activity by ZBTB20. The unique ZBTB20 site was highly conserved in rat and human AFP genes, but absent in albumin genes. These help to explain the autonomous regulation of albumin and AFP genes in the liver after birth. Furthermore, we demonstrated that transcriptional repression of AFP gene by ZBTB20 was liver-specific. ZBTB20 was dispensable for AFP silencing in other tissues outside liver. Our data define a cognate ZBTB20 site in AFP promoter which mediates the postnatal repression of AFP gene in the liver.
Cao D, etal., Nat Commun. 2016 Apr 15;7:11121. doi: 10.1038/ncomms11121.
The anterior pituitary harbours five distinct hormone-producing cell types, and their cellular differentiation is a highly regulated and coordinated process. Here we show that ZBTB20 is essential for anterior pituitary development and lactotrope specification in
mice. In anterior pituitary, ZBTB20 is highly expressed by all the mature endocrine cell types, and to some less extent by somatolactotropes, the precursors of prolactin (PRL)-producing lactotropes. Disruption of Zbtb20 leads to anterior pituitary hypoplasia, hypopituitary dwarfism and a complete loss of mature lactotropes. In ZBTB20-null mice, although lactotrope lineage commitment is normally initiated, somatolactotropes exhibit profound defects in lineage specification and expansion. Furthermore, endogenous ZBTB20 protein binds to Prl promoter, and its knockdown decreases PRL expression and secretion in a lactotrope cell line MMQ. In addition, ZBTB20 overexpression enhances the transcriptional activity of Prl promoter in vitro. In conclusion, our findings point to ZBTB20 as a critical regulator of anterior pituitary development and lactotrope specification.
Lin E, etal., Aging (Albany NY). 2021 Jul 20;13(14):18769-18788. doi: 10.18632/aging.203321. Epub 2021 Jul 20.
The dopamine receptor-related loci have been suggested to be associated with cognitive functions and neurodegenerative diseases. It is unknown whether genetic variants such as single nucleotide polymorphisms (SNPs) in the dopamine receptor-related loci could contribute to cognitive aging independent
ly as well as by virtue of complicated interplays in the elder population. To assess whether SNPs in the dopamine receptor-related loci are associated with cognitive aging in the elder population, we evaluated SNPs in the DRD1, NCAM1-TTC12-ANKK1-DRD2, DRD3-LOC107986115-ZNF80-TIGIT-MIR568-ZBTB20, DRD4, and DRD5-SLC2A9 loci from 25,195 older Taiwanese individuals from the Taiwan Biobank. Mini-Mental State Examination (MMSE) was scrutinized for all participants, where MMSE scores were employed to evaluate cognitive functions. From our analysis, we identified three novel genes for cognitive aging that have not previously been reported: ZBTB20 on chromosome 3 and NCAM1 and TTC12 on chromosome 11. NCAM1 and ZBTB20 are strong candidates for having a role in cognitive aging with mutations in ZBTB20 resulting in intellectual disability, and NCAM1 previously found to be associated with associative memory in humans. Additionally, we found the effects of interplays between physical activity and these three novel genes. Our study suggests that genetic variants in the dopamine receptor-related loci may influence cognitive aging individually and by means of gene-physical activity interactions.
