The m6A modification mediated-lncRNA POU6F2-AS1 reprograms fatty acid metabolism and facilitates the growth of colorectal cancer via upregulation of FASN.

BACKGROUND: Long noncoding RNAs (lncRNAs) have emerged as key players in tumorigenesis and tumour progression. However, the biological functions and potential mechanisms of lncRNAs in colorectal cancer (CRC) are unclear. METHODS: The novel lncRNA POU6F2-AS1 was identified through bioinformatics analysis, and its expression in CRC patients was verified via qRT-PCR and FISH. In vitro and in vivo experiments, such as BODIPY staining, Oil Red O staining, triglyceride (TAG) assays, and liquid chromatography mass spectrometry (LC-MS) were subsequently performed with CRC specimens and cells to determine the clinical significance, and functional roles of POU6F2-AS1. Biotinylated RNA pull-down, RIP, Me-RIP, ChIP, and patient-derived organoid (PDO) culture assays were performed to confirm the underlying mechanism of POU6F2-AS1. RESULTS: The lncRNA POU6F2-AS1 is markedly upregulated in CRC and associated with adverse clinicopathological features and poor overall survival in CRC patients. Functionally, POU6F2-AS1 promotes the growth and lipogenesis of CRC cells both in vitro and in vivo. Mechanistically, METTL3-induced m6A modification is involved in the upregulation of POU6F2-AS1. Furthermore, upregulated POU6F2-AS1 could tether YBX1 to the FASN promoter to induce transcriptional activation, thus facilitating the growth and lipogenesis of CRC cells. CONCLUSIONS: Our data revealed that the upregulation of POU6F2-AS1 plays a critical role in CRC fatty acid metabolism and might provide a novel promising biomarker and therapeutic target for CRC.

Transcriptional Coactivator BOB1 (OBF1, OCA-B) Modulates the Specificity of DNA Recognition by the POU-Domain Factors OCT1 and OCT2 in a Monomeric Configuration.

BOB1, a mammalian lymphocyte-specific transcriptional coactivator of the transcription factors OCT1 and OCT2 (OCT1/2), plays important roles in normal immune responses, autoimmunity, and hematologic malignancies. The issue of a DNA sequence preference change imposed by BOB1 was raised more than two decades ago but remains unresolved. In this paper, using the EMSA-SELEX-Seq approach, we have reassessed the intrinsic ability of BOB1 to modulate the specificity of DNA recognition by OCT1 and OCT2. Our results have reaffirmed previous conclusions regarding BOB1 selectivity towards the dimer configuration of OCT1/2. However, they suggest that the monomeric configuration of these factors, assembled on the classical octamer ATGCAAAT and related motifs, are the primary targets of BOB1. Our data further specify the DNA sequence preference imposed by BOB1 and predict the probability of ternary complex formation. These results provide an additional insight into the action of BOB1-an essential immune regulator and a promising molecular target for the treatment of autoimmune diseases and hematologic malignancies.

Long noncoding RNA POU6F2-AS2 contributes to the aggressiveness of nonsmall-cell lung cancer via microRNA-125b-5p-mediated E2F3 upregulation.

The role of the majority of long noncoding RNAs (lncRNAs) in the progression of nonsmall-cell lung cancer (NSCLC) remains elusive, despite their potential value, thus warranting in-depth studies. For example, detailed functions of the lncRNA POU6F2 antisense RNA 2 (POU6F2-AS2) in NSCLC are unknown. Herein, we investigated the expression status of POU6F2-AS2 in NSCLC. Furthermore, we systematically delineated the biological roles of POU6F2-AS2 in NSCLC alongside its downstream molecular events. We measured the expression levels of POU6F2-AS2 using quantitative real-time polymerase chain reaction and performed a series of functional experiments to address its regulatory effects in NSCLC cells. Using bioinformatic platforms, RNA immunoprecipitation, luciferase reporter assays, and rescue experiments, we investigated the potential mechanisms of POU6F2-AS2 in NSCLC. Subsequently, we confirmed the remarkable overexpression of POU6F2-AS2 in NSCLC using The Cancer Genome Atlas database and our own cohort. Functionally, inhibiting POU6F2-AS2 decreased NSCLC cell proliferation, colony formation, and motility, whereas POU6F2-AS2 overexpression exhibited contrasting effects. Mechanistically, POU6F2-AS2 acts as an endogenous decoy for microRNA-125b-5p (miR-125b-5p) in NSCLC that causes the overexpression of the E2F transcription factor 3 (E2F3). Moreover, suppressing miR-125b-5p or increasing E2F3 expression levels sufficiently recovered the anticarcinostatic activities in NSCLC induced by POU6F2-AS2 silencing. Thus, POU6F2-AS2 aggravates the oncogenicity of NSCLC by targeting the miR-125b-5p/E2F3 axis. Our findings suggest that POU6F2-AS2 is a novel therapeutic target for NSCLC.

LncRNA POU6F2-AS2 contributes to malignant phenotypes and paclitaxel resistance by promoting SKP2 expression in stomach adenocarcinoma.

This study aimed to investigate the role and mechanism of POU6F2-AS2 in the development of gastric cancer. POU6F2-AS2 expression was considerably higher in clinical stomach adenocarcinoma (STAD) tissues and gastric cancer cell lines (MKN-28 and MGC-803) than in neighbouring normal tissues and gastric mucosa epithelial cells (GES-1). POU6F2-AS2 overexpression resulted in a low overall survival probability, progression-free survival probability and post progression survival probability, as well as increased cell viability, migration and invasion of gastric cancer cells, thereby inhibiting apoptosis. Based on RNA pull-down, cycloheximide and MG132 incubation experiments, POU6F2-AS2 promoted SKP2 by stabilizing NONO expression. In addition, in vivo silencing of POU6F2-AS2 in gastric cancer cells can inhibit tumour progression and produce a synergistic antitumour effect when combined with paclitaxel. POU6F2-AS2 is overexpressed in STAD, which is attributed to a bad prognosis. In vitro and in vivo experiments have confirmed that the POU6F2-AS2/NONO/SKP2 axis promotes STAD progression, and that the silencing of POU6F2-AS2 plays a synergistic antitumour effect when combined with paclitaxel. Therefore, POU6F2-AS2 may be potentially developed as a target to inhibit STAD and reduce chemoresistance.

Transcription factor Acj6 controls dendrite targeting via a combinatorial cell-surface code.

Transcription factors specify the fate and connectivity of developing neurons. We investigate how a lineage-specific transcription factor, Acj6, controls the precise dendrite targeting of Drosophila olfactory projection neurons (PNs) by regulating the expression of cell-surface proteins. Quantitative cell-surface proteomic profiling of wild-type and acj6 mutant PNs in intact developing brains, and a proteome-informed genetic screen identified PN surface proteins that execute Acj6-regulated wiring decisions. These include canonical cell adhesion molecules and proteins previously not associated with wiring, such as Piezo, whose mechanosensitive ion channel activity is dispensable for its function in PN dendrite targeting. Comprehensive genetic analyses revealed that Acj6 employs unique sets of cell-surface proteins in different PN types for dendrite targeting. Combined expression of Acj6 wiring executors rescued acj6 mutant phenotypes with higher efficacy and breadth than expression of individual executors. Thus, Acj6 controls wiring specificity of different neuron types by specifying distinct combinatorial expression of cell-surface executors.

POU6F1 cooperates with RORA to suppress the proliferation of lung adenocarcinoma by downregulation HIF1A signaling pathway.

Lung adenocarcinoma (LUAD) represents the most frequently diagnosed histological subtype of non-small cell lung cancer with the highest mortality worldwide. Transcriptional dysregulation is a hallmark of nearly all kinds of cancers. In the study, we identified that the POU domain, class 6, transcription factor 1 (POU6F1), a member of the POU family of transcription factors, was closely associated with tumor stage and death in LUAD. We revealed that POU6F1 was downregulated in LUAD tissues and downregulated POU6F1 was predictive of an unfavorable prognosis in LUAD patients. In vitro assays, including CCK8, soft agar, transwell, clone formation, wound-healing assay, and nude mouse xenograft model all revealed that POU6F1 inhibited the growth and invasion of LUAD cells. Mechanistically, POU6F1 bound and stabilized retinoid-related orphan receptor alpha (RORA) to exert the transcriptional inhibition of hypoxia-inducible factor 1-alpha (HIF1A) and alter the expression of HIF1A signaling pathway-associated genes, including ENO1, PDK1, and PRKCB, thereby leading to the suppression of LUAD cells. Collectively, these results demonstrated the suppressive role of POU6F1/RORA in the progression of LUAD and may potentially be used as a target for the treatment of LUAD.

OCA-T1 and OCA-T2 are coactivators of POU2F3 in the tuft cell lineage.

Tuft cells are a rare chemosensory lineage that coordinates immune and neural responses to foreign pathogens in mucosal tissues1. Recent studies have also revealed tuft-cell-like human tumours2,3, particularly as a variant of small-cell lung cancer. Both normal and neoplastic tuft cells share a genetic requirement for the transcription factor POU2F3 (refs. 2,4), although the transcriptional mechanisms that generate this cell type are poorly understood. Here we show that binding of POU2F3 to the uncharacterized proteins C11orf53 and COLCA2 (renamed here OCA-T1/POU2AF2 and OCA-T2/POU2AF3, respectively) is critical in the tuft cell lineage. OCA-T1 and OCA-T2 are paralogues of the B-cell-specific coactivator OCA-B; all three proteins are encoded in a gene cluster and contain a conserved peptide that binds to class II POU transcription factors and a DNA octamer motif in a bivalent manner. We demonstrate that binding between POU2F3 and OCA-T1 or OCA-T2 is essential in tuft-cell-like small-cell lung cancer. Moreover, we generated OCA-T1-deficient mice, which are viable but lack tuft cells in several mucosal tissues. These findings reveal that the POU2F3-OCA-T complex is the master regulator of tuft cell identity and a molecular vulnerability of tuft-cell-like small-cell lung cancer.

REST Inactivation and Coexpression of ASCL1 and POU3F4 Are Necessary for the Complete Transformation of RB1/TP53-Inactivated Lung Adenocarcinoma into Neuroendocrine Carcinoma.

Although recent reports have revealed the importance of the inactivation of both RB1 and TP53 in the transformation from lung adenocarcinoma into neuroendocrine carcinoma (NEC), the requirements for complete transformation into NEC have not been elucidated. To investigate alterations in the characteristics associated with the inactivation of RB1/TP53 and define the requirements for transformation into NEC cells, RB1/TP53 double-knockout A549 lung adenocarcinoma cells were established, and additional knockout of REST and transfection of ASCL1 and POU class 3 homeobox transcription factors (TFs) was conducted. More than 60 genes that are abundantly expressed in neural cells and several genes associated with epithelial-to-mesenchymal transition were up-regulated in RB1/TP53 double-knockout A549 cells. Although the expression of chromogranin A and synaptophysin was induced by additional knockout of REST (which mimics the status of most NECs), the expression of another neuroendocrine marker, CD56, and proneural TFs was not induced. However, coexpression of ASCL1 and POU3F4 in RB1/TP53/REST triple-knockout A549 cells induced the expression of not only CD56 but also other proneural TFs (NEUROD1 and insulinoma-associated 1) and induced NEC-like morphology. These findings suggest that the inactivation of RB1 and TP53 induces a state necessary for the transformation of lung adenocarcinoma into NEC and that further inactivation of REST and coexpression of ASCL1 and POU3F4 are the triggers for complete transformation into NEC.

Neuronal identities derived by misexpression of the POU IV sensory determinant in a protovertebrate.

The protovertebrate Ciona intestinalis type A (sometimes called Ciona robusta) contains a series of sensory cell types distributed across the head-tail axis of swimming tadpoles. They arise from lateral regions of the neural plate that exhibit properties of vertebrate placodes and neural crest. The sensory determinant POU IV/Brn3 is known to work in concert with regional determinants, such as Foxg and Neurogenin, to produce palp sensory cells (PSCs) and bipolar tail neurons (BTNs), in head and tail regions, respectively. A combination of single-cell RNA-sequencing (scRNA-seq) assays, computational analysis, and experimental manipulations suggests that misexpression of POU IV results in variable transformations of epidermal cells into hybrid sensory cell types, including those exhibiting properties of both PSCs and BTNs. Hybrid properties are due to coexpression of Foxg and Neurogenin that is triggered by an unexpected POU IV feedback loop. Hybrid cells were also found to express a synthetic gene battery that is not coexpressed in any known cell type. We discuss these results with respect to the opportunities and challenges of reprogramming cell types through the targeted misexpression of cellular determinants.

BRN2 and MITF together impact AXL expression in melanoma.

The inverse relationship between transcription factor MITF and receptor tyrosine kinase AXL has received much attention recently. It is thought that melanoma tumors showing AXLhigh /MITFlow levels are resistant to therapy. We show here that a population of cells within melanoma tumors with extremely high expression of AXL are negative/low for both MITF and the transcription factor BRN2. Depletion of both transcription factors from cultured melanoma cell lines produced an increase in AXL expression greater than depletion of MITF alone. Further, re-expression of BRN2 led to decreased AXL expression, indicating a role for BRN2 in regulation of AXL levels unrelated to effects on MITF level. As AXL has been recognized as a marker of therapy resistance, these cells may represent a population of cells responsible for disease relapse and as potential targets for therapeutic treatment.

Identification of Differentially Expressed Genes Particularly Associated with Immunity in Uremia Patients by Bioinformatic Analysis.

Uremia is a common syndrome that happens to nearly all end-stage kidney diseases, which profound have changes in human gene expressions, but the related pathways are poorly understood. Gene Ontology categories and Kyoto Encyclopedia of Genes and Genomes pathways enriched in the differentially expressed genes (DEGs) were analyzed by using clusterProfiler, org.Hs.eg.db, and Pathview, and protein-protein interaction (PPI) network was built by Cytoscape. We identified 3432 DEGs (including 3368 down- and 64 up-regulated genes), of which there were 52 different molecular functions, and 178 genes were identified as immune genes controlled by the four transcription factors (POU domain class 6 transcription factor 1 (POU6F1), interferon regulator factor 7 [IRF7], forkhead box D3 (FOXD3), and interferon-stimulated response element [ISRE]). In the gender research, no significant difference was observed. The top 15 proteins of 178 immune-related genes were identified with the highest degree in PPI network. The DEG analysis of uremia patients was expected to provide fundamental information to relieve pain and add years to their life.

Cnidarian hair cell development illuminates an ancient role for the class IV POU transcription factor in defining mechanoreceptor identity.

Although specialized mechanosensory cells are found across animal phylogeny, early evolutionary histories of mechanoreceptor development remain enigmatic. Cnidaria (e.g. sea anemones and jellyfishes) is the sister group to well-studied Bilateria (e.g. flies and vertebrates), and has two mechanosensory cell types - a lineage-specific sensory effector known as the cnidocyte, and a classical mechanosensory neuron referred to as the hair cell. While developmental genetics of cnidocytes is increasingly understood, genes essential for cnidarian hair cell development are unknown. Here, we show that the class IV POU homeodomain transcription factor (POU-IV) - an indispensable regulator of mechanosensory cell differentiation in Bilateria and cnidocyte differentiation in Cnidaria - controls hair cell development in the sea anemone cnidarian Nematostella vectensis. N. vectensis POU-IV is postmitotically expressed in tentacular hair cells, and is necessary for development of the apical mechanosensory apparatus, but not of neurites, in hair cells. Moreover, it binds to deeply conserved DNA recognition elements, and turns on a unique set of effector genes - including the transmembrane receptor-encoding gene polycystin 1 - specifically in hair cells. Our results suggest that POU-IV directs differentiation of cnidarian hair cells and cnidocytes via distinct gene regulatory mechanisms, and support an evolutionarily ancient role for POU-IV in defining the mature state of mechanosensory neurons.

The neuroblast timer gene nubbin exhibits functional redundancy with gap genes to regulate segment identity in Tribolium.

The neuroblast timer genes hunchback, Krüppel, nubbin and castor are expressed in temporal sequence in neural stem cells, and in corresponding spatial sequence along the Drosophila blastoderm. As canonical gap genes, hunchback and Krüppel play a crucial role in insect segmentation, but the roles of nubbin and castor in this process remain ambiguous. We have investigated the expression and functions of nubbin and castor during segmentation in the beetle Tribolium. We show that Tc-hunchback, Tc-Krüppel, Tc-nubbin and Tc-castor are expressed sequentially in the segment addition zone, and that Tc-nubbin regulates segment identity redundantly with two previously described gap/gap-like genes, Tc-giant and Tc-knirps. Simultaneous knockdown of Tc-nubbin, Tc-giant and Tc-knirps results in the formation of ectopic legs on abdominal segments. This homeotic transformation is caused by loss of abdominal Hox gene expression, likely due to expanded Tc-Krüppel expression. Our findings support the theory that the neuroblast timer series was co-opted for use in insect segment patterning, and contribute to our growing understanding of the evolution and function of the gap gene network outside of Drosophila.

Effect of Linc-POU3F3 on radiotherapy resistance and cancer stem cell markers of esophageal cancer cells. / Linc-POU3F3å¯¹é£Ÿç®¡ç™Œç»†èƒžæ”¾å°„æ²»ç–—æŠµæŠ—åŠè‚¿ç˜¤å¹²ç»†èƒžæ ‡å¿—ç‰©çš„å½±å“.

OBJECTIVES: Long non-coding RNA (LncRNA) is an important transcriptional and post-transcriptional regulatory molecule in the body. In recent years, relationship between LncRNA and malignant phenotype of tumor cells has been revealed gradually. This study aims to investigate the expression characteristics of pit-oct-unc class 3 homeobox 3 related long non-coding RNA (Linc-POU3F3) in esophageal cancer and its relationship with radiation resistance (IR) as well as the expressions of cancer stem cell (CSC) markers in esophageal cancer cells. METHODS: The expression characteristics and potential interaction molecules of Linc-POU3F3 in esophageal cancer were collected from the public database via bioinformatics retrieval. Forty-two pair samples of esophageal cancer tissues and corresponding adjacent tissues were collected. Human normal esophageal epithelial cells (HEEC) and human esophageal cancer cell lines (ECA109, TE-1, TE-2, TE-13) were cultured. Real-time quantitative PCR (qPCR) was used to detect the expression level of Linc-POU3F3 in clinical tissues and cells. The formation of TE-13 IR cell line induced by different doses of radiation served as IR group cells, and the same condition treated with 0 Gy dose was set as control group (control) cells. Meanwhile, we used cell transfection technology to construct random interference sequence (siControl) cells and interference (siLinc-POU3F3) cells. In ECA109 cells, we transfected blank and over expressed Linc-POU3F3 plasmids as vector and over-expressed group (oeLinc-POU3F3). The mRNA and protein expressions of CD44, CD133 and CD90 were detected by qPCR and Western blotting, respectively. MTS [3-(4,5-dimenthylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt] was used to detect the cell viability under different radiation doses, and the resistance of IR cells was verified by clone formation experiment. RESULTS: The expression of Linc-POU3F3 was correlated with the tumor progression and poor prognosis of esophageal cancer. The level of Linc-POU3F3 mRNA expression was significantly higher in esophageal cancer tissues and cell lines than that in normal adjacent tissues and cell lines (all P<0.01). The expressions of Linc-POU3F3 mRNA and protein expressions of CD44, CD133, and CD90 in IR cells were significantly higher than those in control cells (all P<0.01). The expression of Linc-POU3F3 in siLinc-POU3F3 cell was significantly lower than that in the siControl cells (P<0.01), and the inhibition rate was 87.21%. The mRNA and protein expressions of CD44, CD133, and CD90 in the siLinc-POU3F3 cells were significantly lower than those in the siControl cells (all P<0.05). The expressions of linc-POU3F3, CD44, CD133, and CD90 mRNA and protein in the oeLinc-POU3F3 cells were significantly higher than those in the vector cells. The relative activity and clone formation ability in the IR cells were significantly higher than those in the control cells at 2, 4, and 8 Gy doses (all P<0.01). The relative activity in the siLinc-POU3F3 cells was significantly lower than that in the siControl cells at 4 and 8 Gy doses (P<0.01). The relative activity in the oeLinc-POU3F3 cells was significantly higher than that in the vector cells at 4 and 8 Gy doses (P<0.01). CONCLUSIONS: Linc-POU3F3 is up-regulated in esophageal cancer and can promote IR and the expression of CSC markers in esophageal cancer cells.

BRN2 is a non-canonical melanoma tumor-suppressor.

While the major drivers of melanoma initiation, including activation of NRAS/BRAF and loss of PTEN or CDKN2A, have been identified, the role of key transcription factors that impose altered transcriptional states in response to deregulated signaling is not well understood. The POU domain transcription factor BRN2 is a key regulator of melanoma invasion, yet its role in melanoma initiation remains unknown. Here, in a BrafV600E PtenF/+ context, we show that BRN2 haplo-insufficiency promotes melanoma initiation and metastasis. However, metastatic colonization is less efficient in the absence of Brn2. Mechanistically, BRN2 directly induces PTEN expression and in consequence represses PI3K signaling. Moreover, MITF, a BRN2 target, represses PTEN transcription. Collectively, our results suggest that on a PTEN heterozygous background somatic deletion of one BRN2 allele and temporal regulation of the other allele elicits melanoma initiation and progression.

STAG2 loss rewires oncogenic and developmental programs to promote metastasis in Ewing sarcoma.

The core cohesin subunit STAG2 is recurrently mutated in Ewing sarcoma but its biological role is less clear. Here, we demonstrate that cohesin complexes containing STAG2 occupy enhancer and polycomb repressive complex (PRC2)-marked regulatory regions. Genetic suppression of STAG2 leads to a compensatory increase in cohesin-STAG1 complexes, but not in enhancer-rich regions, and results in reprogramming of cis-chromatin interactions. Strikingly, in STAG2 knockout cells the oncogenic genetic program driven by the fusion transcription factor EWS/FLI1 was highly perturbed, in part due to altered enhancer-promoter contacts. Moreover, loss of STAG2 also disrupted PRC2-mediated regulation of gene expression. Combined, these transcriptional changes converged to modulate EWS/FLI1, migratory, and neurodevelopmental programs. Finally, consistent with clinical observations, functional studies revealed that loss of STAG2 enhances the metastatic potential of Ewing sarcoma xenografts. Our findings demonstrate that STAG2 mutations can alter chromatin architecture and transcriptional programs to promote an aggressive cancer phenotype.

Pou5f3.3 is involved in establishment and maintenance of hematopoietic cells during Xenopus development.

Three POU family class V gene homologues are expressed in the development of Xenopus. In contrast to the expression of Pou5f3.1 and Pou5f3.2 in organogenesis, Pou5f3.3 is expressed during oogenesis in ovary. We investigated the expression and function of Pou5f3.3 in organogenesis of Xenopus laevis. RT-PCR and immunohistochemical analysis indicated that Pou5f3.3 was expressed in a small number of adult liver cells and blood cells. Immunocytochemical investigation proved that Bmi1, a marker for hematopoietic progenitor cells, was co-expressed in Pou5f3.3-expressing small spherical cells in the peripheral blood. In anemic induction by intraperitoneal injection of phenyl hydrazine, the number of Pou5f3.3-expressing cells significantly increased within 3 days after phenyl hydrazine injection. In CRISPR/Cas mutagenesis of Pou5f3.3, Bmi1-positive hematopoietic progenitor cell count decreased in the hematopoietic dorsal-lateral plate (DLP) region, resulting in a considerable reduction in peripheral blood cells. CRISPR/Cas-induced hematopoietic deficiency was completely rescued by Pou5f3.3 supplementation, but not by Pou5f3.1 or Pou5f3.2. Transplantation experiments using the H2B-GFP transgenic line demonstrated that DLP-derived Pou5f3.3-positive and Bmi1-positive cells were translocated into the liver and bone through the bloodstream. These results suggest that Pou5f3.3 plays an essential role in the establishment and maintenance of hematopoietic progenitor cells during Xenopus development.

Progenitor cell diversity in the developing mouse neocortex.

In the mammalian neocortex, projection neuron types are sequentially generated by the same pool of neural progenitors. How neuron type specification is related to developmental timing remains unclear. To determine whether temporal gene expression in neural progenitors correlates with neuron type specification, we performed single-cell RNA sequencing (scRNA-Seq) analysis of the developing mouse neocortex. We uncovered neuroepithelial cell enriched genes such as Hmga2 and Ccnd1 when compared to radial glial cells (RGCs). RGCs display dynamic gene expression over time; for instance, early RGCs express higher levels of Hes5, and late RGCs show higher expression of Pou3f2 Interestingly, intermediate progenitor cell marker gene Eomes coexpresses temporally with known neuronal identity genes at different developmental stages, though mostly in postmitotic cells. Our results delineate neural progenitor cell diversity in the developing mouse neocortex and support that neuronal identity genes are transcriptionally evident in Eomes-positive cells.

Research progress of the transcription factor Brn4 (Review).

Brain 4 (Brn4) is a transcription factor belonging to the POU3 family, and it is important for the embryonic development of the neural tube, inner ear and pancreas. In addition, it serves a crucial role in neural stem cell differentiation and reprogramming. The present review aimed to summarize the chromosomal location, species homology, protein molecular structure and tissue distribution of Brn4, in addition to its biological processes, with the aim of providing a reference of its structure and function for further studies, and its potential use as a gene therapy target.

Transcription factor POU3F2 regulates TRIM8 expression contributing to cellular functions implicated in schizophrenia.

Schizophrenia (SCZ) is a neuropsychiatric disorder with aberrant expression of multiple genes. However, identifying its exact causal genes remains a considerable challenge. The brain-specific transcription factor POU3F2 (POU domain, class 3, transcription factor 2) has been recognized as a risk factor for SCZ, but our understanding of its target genes and pathogenic mechanisms are still limited. Here we report that POU3F2 regulates 42 SCZ-related genes in knockdown and RNA-sequencing experiments of human neural progenitor cells (NPCs). Among those SCZ-related genes, TRIM8 (Tripartite motif containing 8) is located in SCZ-associated genetic locus and is aberrantly expressed in patients with SCZ. Luciferase reporter and electrophoretic mobility shift assays (EMSA) showed that POU3F2 induces TRIM8 expression by binding to the SCZ-associated SNP (single nucleotide polymorphism) rs5011218, which affects POU3F2-binding efficiency at the promoter region of TRIM8. We investigated the cellular functions of POU3F2 and TRIM8 as they co-regulate several pathways related to neural development and synaptic function. Knocking down either POU3F2 or TRIM8 promoted the proliferation of NPCs, inhibited their neuronal differentiation, and impaired the excitatory synaptic transmission of NPC-derived neurons. These results indicate that POU3F2 regulates TRIM8 expression through the SCZ-associated SNP rs5011218, and both genes may be involved in the etiology of SCZ by regulating neural development and synaptic function.