Dimerization of hub protein DYNLL1 and bZIP transcription factor CREB3L1 enhances transcriptional activation of CREB3L1 target genes like arginine vasopressin.

bZIP transcription factors can function as homodimers or heterodimers through interactions with their disordered coiled-coil domain. Such dimer assemblies are known to influence DNA-binding specificity and/or the recruitment of binding partners, which can cause a functional switch of a transcription factor from being an activator to a repressor. We recently identified the genomic targets of a bZIP transcription factor called CREB3L1 in rat hypothalamic supraoptic nucleus by ChIP-seq. The objective of this study was to investigate the CREB3L1 protein-to-protein interactome of which little is known. For this approach, we created and screened a rat supraoptic nucleus yeast two-hybrid prey library with the bZIP region of rat CREB3L1 as the bait. Our yeast two-hybrid approach captured five putative CREB3L1 interacting prey proteins in the supraoptic nucleus. One interactor was selected by bioinformatic analyses for more detailed investigation by co-immunoprecipitation, immunofluorescent cellular localisation, and reporter assays in vitro. Here we identify dimerisation hub protein Dynein Light Chain LC8-Type 1 as a CREB3L1 interacting protein that in vitro enhances CREB3L1 activation of target genes.

[Overexpression of BZW1 promotes invasion and metastasis of gastric cancer cells by regulating Wnt/ß-catenin signaling and promoting epithelial-mesenchymal transition].

OBJECTIVE: To investigate the expression level of basic leucine zipper and W2 domain-containing protein 1 (BZW1) in gastric cancer, its impact on patient prognosis and the underlying mechanisms. METHODS: TIMER, UALCAN and Kaplan-Meier Plotter databases were used for analyzing BZW1 expression level gastric cancer tissues and its correlation with tumor grade and stage and the patients' prognosis. We further analyzed BZW1 expressions, disease progression, and postoperative 5-year survival in 102 patients undergoing radical surgery for gastric cancer at our hospital between January, 2014 and December, 2016. Gastric cancer MGC803 cells were examined for changes in migration, invasion, and epithelial-mesenchymal transition (EMT) following lentivirus-mediated BZW1 overexpression or knockdown. RESULTS: The protein and mRNA expressions of BZW1 in gastric cancer tissues were 3.30 and 6.54 times of those in adjacent tissues, respectively (P < 0.01). BZW1 expression in gastric cancer tissues were positively correlated with peripheral blood CEA and CA199 levels (P < 0.01). A high BZW1 expression was an independent risk factor for 5-year survival of gastric cancer patients after radical surgery (P < 0.05, HR=2.070, 95%CI: 1.021-4.196). At the cut-off value of 3.61, BZW1 expression had a sensitivity of 75.56% and a specificity of 71.93% for predicting postoperative 5-year mortality (P < 0.01). In MGC803 cells, BZW1 overexpression obviously promoted cell migration and invasion (P < 0.05), enhanced cellular expressions of N-cadherin and vimentin (P < 0.05) and inhibited the expression of E-cadherin (P < 0.05). Enrichment analysis suggested the involvement of BZW1 in the Wnt/ß-catenin signaling pathway. Western blotting confirmed that BZW1 overexpression promoted while BZW1 knockdown inhibited the expressions of Wnt3a, ß-catenin and C-myc in MGC803 cells (P < 0.05). CONCLUSION: BZW1 is highly expressed in gastric cancer tissues to affect the patient prognosis possibly by activation the Wnt/ß-catenin signaling pathway to promote EMT of gastric cancer cells.

Concise review: The heterogenous roles of BATF3 in cancer oncogenesis and dendritic cells and T cells differentiation and function considering the importance of BATF3-dependent dendritic cells.

The transcription factor, known as basic leucine zipper ATF-like 3 (BATF3), is a crucial contributor to the development of conventional type 1 dendritic cells (cDC1), which is definitely required for priming CD8 + T cell-mediated immunity against intracellular pathogens and malignancies. In this respect, BATF3-dependent cDC1 can bring about immunological tolerance, an autoimmune response, graft immunity, and defense against infectious agents such as viruses, microbes, parasites, and fungi. Moreover, the important function of cDC1 in stimulating CD8 + T cells creates an excellent opportunity to develop a highly effective target for vaccination against intracellular pathogens and diseases. BATF3 has been clarified to control the development of CD8α+ and CD103+ DCs. The presence of BATF3-dependent cDC1 in the tumor microenvironment (TME) reinforces immunosurveillance and improves immunotherapy approaches, which can be beneficial for cancer immunotherapy. Additionally, BATF3 acts as a transcriptional inhibitor of Treg development by decreasing the expression of the transcription factor FOXP3. However, when overexpressed in CD8 + T cells, it can enhance their survival and facilitate their transition to a memory state. BATF3 induces Th9 cell differentiation by binding to the IL-9 promoter through a BATF3/IRF4 complex. One of the latest research findings is the oncogenic function of BATF3, which has been approved and illustrated in several biological processes of proliferation and invasion.

[Role of post-translational modification of basic leucine zipper transcription factors in response to abiotic stresses in plants].

Abiotic stresses substantially affect the growth and development of plants. Plants have evolved multiple strategies to cope with the environmental stresses, among which transcription factors play an important role in regulating the tolerance to abiotic stresses. Basic leucine zipper transcription factors (bZIP) are one of the largest gene families. The stability and activity of bZIP transcription factors could be regulated by different post-translational modifications (PTMs) in response to various intracellular or extracellular stresses. This paper introduces the structural feature and classification of bZIP transcription factors, followed by summarizing the PTMs of bZIP transcription factors, such as phosphorylation, ubiquitination and small ubiquitin-like modifier (SUMO) modification, in response to abiotic stresses. In addition, future perspectives were prospected, which may facilitate cultivating excellent stress-resistant crop varieties by regulating the PTMs of bZIP transcription factors.

Genome-Wide Identification and Expression Analysis of bZIP Family Genes in Stevia rebaudiana.

The basic (region) leucine zippers (bZIPs) are evolutionarily conserved transcription factors widely distributed in eukaryotic organisms. In plants, they are not only involved in growth and development, defense and stress responses and regulation of physiological processes but also play a pivotal role in regulating secondary metabolism. To explore the function related to the bZIP gene family in Stevia rebaudiana Bertoni, we identified 105 SrbZIP genes at the genome-wide level and classified them into 12 subfamilies using bioinformation methods. Three main classes of cis-acting elements were found in the SrbZIP promoter regions, including development-related elements, defense and stress-responsive elements and phytohormone-responsive elements. Through protein-protein interaction network of 105 SrbZIP proteins, SrbZIP proteins were mainly classified into four major categories: ABF2/ABF4/ABI5 (SrbZIP51/SrbZIP38/SrbZIP7), involved in phytohormone signaling, GBF1/GBF3/GBF4 (SrbZIP29/SrbZIP63/SrbZIP60) involved in environmental signaling, AREB3 (SrbZIP88), PAN (SrbZIP12), TGA1 (SrbZIP69), TGA4 (SrbZIP82), TGA7 (SrbZIP31), TGA9 (SrbZIP95), TGA10 (SrbZIP79) and HY5 (SrbZIP96) involved in cryptochrome signaling, and FD (SrbZIP72) promoted flowering. The transcriptomic data showed that SrbZIP genes were differentially expressed in six S. rebaudiana cultivars ('023', '110', 'B1188', '11-14', 'GP' and 'GX'). Moreover, the expression levels of selected 15 SrbZIP genes in response to light, abiotic stress (low temperature, salt and drought), phytohormones (methyl jasmonate, gibberellic acid and salicylic acid) treatment and in different tissues were analyzed utilizing qRT-PCR. Some SrbZIP genes were further identified to be highly induced by factors affecting glycoside synthesis. Among them, three SrbZIP genes (SrbZIP54, SrbZIP63 and SrbZIP32) were predicted to be related to stress-responsive terpenoid synthesis in S. rebaudiana. The protein-protein interaction network expanded the potential functions of SrbZIP genes. This study firstly provided the comprehensive genome-wide report of the SrbZIP gene family, laying a foundation for further research on the evolution, function and regulatory role of the bZIP gene family in terpenoid synthesis in S. rebaudiana.

Ferroptosis model system by the re-expression of BACH1.

Ferroptosis is a regulated cell death induced by iron-dependent lipid peroxidation. The heme-responsive transcription factor BTB and CNC homology 1 (BACH1) promotes ferroptosis by repressing the transcription of genes involved in glutathione (GSH) synthesis and intracellular labile iron metabolism, which are key regulatory pathways in ferroptosis. We found that BACH1 re-expression in Bach1-/- immortalized mouse embryonic fibroblasts (iMEFs) can induce ferroptosis upon 2-mercaptoethanol removal, without any ferroptosis inducers. In these iMEFs, GSH synthesis was reduced, and intracellular labile iron levels were increased upon BACH1 re-expression. We used this system to investigate whether the major ferroptosis regulators glutathione peroxidase 4 (Gpx4) and apoptosis-inducing factor mitochondria-associated 2 (Aifm2), the gene for ferroptosis suppressor protein 1, are target genes of BACH1. Neither Gpx4 nor Aifm2 was regulated by BACH1 in the iMEFs. However, we found that BACH1 represses AIFM2 transcription in human pancreatic cancer cells. These results suggest that the ferroptosis regulators targeted by BACH1 may vary across different cell types and animal species. Furthermore, we confirmed that the ferroptosis induced by BACH1 re-expression exhibited a propagating effect. BACH1 re-expression represents a new strategy for inducing ferroptosis after GPX4 or system Xc- suppression and is expected to contribute to future ferroptosis research.

Substrate profiling of the Arabidopsis Ca2+-dependent protein kinase AtCPK4 and its Ricinus communis ortholog RcCDPK1.

AtCPK4 and AtCPK11 are Arabidopsis thaliana Ca2+-dependent protein kinase (CDPK) paralogs that have been reported to positively regulate abscisic acid (ABA) signal transduction by phosphorylating ABA-responsive transcription factor-4 (AtABF4). By contrast, RcCDPK1, their closest Ricinus communis ortholog, participates in the control of anaplerotic carbon flux in developing castor oil seeds by catalyzing inhibitory phosphorylation of bacterial-type phosphoenolpyruvate carboxylase at Ser451. LC-MS/MS revealed that AtCPK4 and RcCDPK1 transphosphorylated several common, conserved residues of AtABF4 and its castor ortholog, TRANSCRIPTION FACTOR RESPONSIBLE FOR ABA REGULATON. Arabidopsis atcpk4/atcpk11 mutants displayed an ABA-insensitive phenotype that corroborated the involvement of AtCPK4/11 in ABA signaling. A kinase-client assay was employed to identify additional AtCPK4/RcCDPK1 targets. Both CDPKs were separately incubated with a library of 2095 peptides representative of Arabidopsis protein phosphosites; five overlapping targets were identified including PLANT INTRACELLULAR RAS-GROUP-RELATED LEUCINE-RICH REPEAT PROTEIN-9 (AtPIRL9) and the E3-ubiquitin ligase ARABIDOPSIS TOXICOS EN LEVADURA 6 (AtATL6). AtPIRL9 and AtATL6 residues phosphorylated by AtCPK4/RcCDPK1 conformed to a CDPK recognition motif that was conserved amongst their respective orthologs. Collectively, this study provides evidence for novel AtCPK4/RcCDPK1 substrates, which may help to expand regulatory networks linked to Ca2+- and ABA-signaling, immune responses, and central carbon metabolism.

Disrupting Sc-uORFs of a transcription factor bZIP1 using CRISPR/Cas9 enhances sugar and amino acid contents in tomato (Solanum lycopersicum).

MAIN CONCLUSION: Induced mutations in the SC-uORF of the tomato transcription factor gene SlbZIP1 by the CRISPR/Cas9 system led to the high accumulation of sugar and amino acid contents in tomato fruits. Tomato (Solanum lycopersicum) is one of the most popular and consumed vegetable crops in the world. Among important traits for tomato improvement such as yield, biotic and abiotic resistances, appearance, post-harvest shelf life and fruit quality, the last one seems to face more challenges because of its genetic and biochemical complexities. In this study, a dual-gRNAs CRISPR/Cas9 system was developed to induce targeted mutations in uORF regions of the SlbZIP1, a gene involved in the sucrose-induced repression of translation (SIRT) mechanism. Different induced mutations in the SlbZIP1-uORF region were identified at the T0 generation, stably transferred to the offspring, and no mutation was found at potential off-target sites. The induced mutations in the SlbZIP1-uORF region affected the transcription of SlbZIP1 and related genes in sugar and amino acid biosynthesis. Fruit component analysis showed significant increases in soluble solid, sugar and total amino acid contents in all SlbZIP1-uORF mutant lines. The accumulation of sour-tasting amino acids, including aspartic and glutamic acids, raised from 77 to 144%, while the accumulation of sweet-tasting amino acids such as alanine, glycine, proline, serine, and threonine increased from 14 to 107% in the mutant plants. Importantly, the potential SlbZIP1-uORF mutant lines with desirable fruit traits and no impaired effect on plant phenotype, growth and development were identified under the growth chamber condition. Our result indicates the potential utility of the CRISPR/Cas9 system for fruit quality improvement in tomato and other important crops.

HvbZIP21, a Novel Transcription Factor From Wild Barley Confers Drought Tolerance by Modulating ROS Scavenging.

Drought stress is a common environmental stress, which adversely affects the yield and quality of crops. Due to its excellent drought tolerance, wild barley from the Middle East region is considered a valuable source for barley improvement. Here, we compared the growth rate, stomatal regulation and capacity to metabolize reactive oxygen species (ROS) of two barley cultivars and one wild barley accession. The results indicated the wild barley EC_S1 showed a more significant decline in stomatal aperture and less ROS production. Transcriptomic analysis revealed that EC_S1 has slower transcriptional regulation (5,050 DEGs) in the early stage of drought stress (14 days) than Baudin (7,022 DEGs) and Tadmor (6,090 DEGs). In addition, 30 hub genes, including nine known drought-related genes were identified by WGCNA analysis. Then, we cloned a novel bZIP transcription factor, HvbZIP21, from EC_S1. HvbZIP21 was subcellularly targeted to the nucleus. Overexpression of HvbZIP21 in Arabidopsis enhanced drought tolerance due to increasing activities of superoxide dismutase, peroxidase, and catalase activities as well as glutathione content. Silencing of HvbZIP21 in EC_S1 suppressed drought tolerance in BSMV:HvbZIP21-inoculated plants. Taken together, our findings suggest that HvbZIP21 play a critical role in drought tolerance by manipulating ROS scavenging.

Designing synthetic transcription factors: A structural perspective.

In this chapter, we discuss different design strategies of synthetic proteins, especially synthetic transcription factors. Design and engineering of synthetic transcription factors is particularly relevant for the need-based manipulation of gene expression. With recent advances in structural biology techniques and with the emergence of other precision biochemical/physical tools, accurate knowledge on structure-function relations is increasingly becoming available. Besides discussing the underlying principles of design, we go through individual cases, especially those involving four major groups of transcription factors-basic leucine zippers, zinc fingers, helix-turn-helix and homeodomains. We further discuss how synthetic biology can come together with structural biology to alter the genetic blueprint of life.

Structural insights into cooperative DNA recognition by the CCAAT-binding complex and its bZIP transcription factor HapX.

The heterotrimeric CCAAT-binding complex (CBC) is a fundamental eukaryotic transcription factor recognizing the CCAAT box. In certain fungi, like Aspergilli, the CBC cooperates with the basic leucine zipper HapX to control iron metabolism. HapX functionally depends on the CBC, and the stable interaction of both requires DNA. To study this cooperative effect, X-ray structures of the CBC-HapX-DNA complex were determined. Downstream of the CCAAT box, occupied by the CBC, a HapX dimer binds to the major groove. The leash-like N terminus of the distal HapX subunit contacts the CBC, and via a flexible polyproline type II helix mediates minor groove interactions that stimulate sequence promiscuity. In vitro and in vivo mutagenesis suggest that the structural and functional plasticity of HapX results from local asymmetry and its ability to target major and minor grooves simultaneously. The latter feature may also apply to related transcription factors such as yeast Hap4 and distinct Yap family members.

The basic leucine zipper transcription factor OsbZIP83 and the glutaredoxins OsGRX6 and OsGRX9 facilitate rice iron utilization under the control of OsHRZ ubiquitin ligases.

Under low iron availability, plants induce the expression of various genes for iron uptake and translocation. The rice (Oryza sativa) ubiquitin ligases OsHRZ1 and OsHRZ2 cause overall repression of these iron-related genes at the transcript level, but their protein-level regulation is unclear. We conducted a proteome analysis to identify key regulators whose abundance was regulated by OsHRZs at the protein level. In response to iron deficiency or OsHRZ knockdown, many genes showed differential regulation between the transcript and protein levels, including the TGA-type basic leucine zipper transcription factor OsbZIP83. We also identified two glutaredoxins, OsGRX6 and OsGRX9, as OsHRZ-interacting proteins in yeast and plant cells. OsGRX6 also interacted with OsbZIP83. Our in vitro degradation assay suggested that OsbZIP83, OsGRX6 and OsGRX9 proteins are subjected to 26S proteasome- and OsHRZ-dependent degradation. Proteome analysis and our in vitro degradation assay also suggested that OsbZIP83 protein was preferentially degraded under iron-deficient conditions in rice roots. Transgenic rice lines overexpressing OsGRX9 and OsbZIP83 showed improved tolerance to iron deficiency. Expression of iron-related genes was affected in the OsGRX9 and OsGRX6 knockdown lines, suggesting disturbed iron utilization and signaling. OsbZIP83 overexpression lines showed enhanced expression of OsYSL2 and OsNAS3, which are involved in internal iron translocation, in addition to OsGRX9 and genes related to phytoalexin biosynthesis and the salicylic acid pathway. The results suggest that OsbZIP83, OsGRX6 and OsGRX9 facilitate iron utilization downstream of the OsHRZ pathway.

OsbZIP18, a Positive Regulator of Serotonin Biosynthesis, Negatively Controls the UV-B Tolerance in Rice.

Serotonin (5-hydroxytryptamine) plays an important role in many developmental processes and biotic/abiotic stress responses in plants. Although serotonin biosynthetic pathways in plants have been uncovered, knowledge of the mechanisms of serotonin accumulation is still limited, and no regulators have been identified to date. Here, we identified the basic leucine zipper transcription factor OsbZIP18 as a positive regulator of serotonin biosynthesis in rice. Overexpression of OsbZIP18 strongly induced the levels of serotonin and its early precursors (tryptophan and tryptamine), resulting in stunted growth and dark-brown phenotypes. A function analysis showed that OsbZIP18 activated serotonin biosynthesis genes (including tryptophan decarboxylase 1 (OsTDC1), tryptophan decarboxylase 3 (OsTDC3), and tryptamine 5-hydroxylase (OsT5H)) by directly binding to the ACE-containing or G-box cis-elements in their promoters. Furthermore, we demonstrated that OsbZIP18 is induced by UV-B stress, and experiments using UV-B radiation showed that transgenic plants overexpressing OsbZIP18 exhibited UV-B stress-sensitive phenotypes. Besides, exogenous serotonin significantly exacerbates UV-B stress of OsbZIP18_OE plants, suggesting that the excessive accumulation of serotonin may be responsible for the sensitivity of OsbZIP18_OE plants to UV-B stress. Overall, we identified a positive regulator of serotonin biosynthesis and demonstrated that UV-B-stress induced serotonin accumulation, partly in an OsbZIP18-dependent manner.

Diagnostic and prognostic role of basic leucine zipper transcription factor in kidney renal clear cell carcinoma.

Background: Basic leucine zipper transcription factor (BATF) plays a crucial role in development and progression of different types of carcinomas. However, its prognostic value in kidney renal clear cell carcinoma (KIRC) is yet to be elucidated. Methods: We obtained clinicopathological data and expression profiles of BATF from The Cancer Genome Atlas (TCGA) on the pan-cancer and KIRC perspectives. We calculated the area under the curve (AUC) of the receiver-operating characteristic curves to understand the discriminatory capacity of BATF. Next, we generated Kaplan-Meier curves to assess the effect of BATF on the overall survival (OS) of patients, then performed univariate and multivariate Cox regression analyses. Subsequently, we used multivariate regression to construct a nomogram for predicting prognosis. Furthermore, we construct a protein-protein interaction (PPI) network, then performed gene set enrichment and pathway enrichment analyses to determine the biological function of the co-expression genes. Finally, we performed tumor microenvironment analyses to establish the relationship between BATF expression and infiltrating immune cells. Results: BATF was significantly upregulated in KIRC relative to normal kidney tissues. Upregulation of BATF mRNA was associated with higher TNM pathological stage, histological grade, and poor OS/PFI (progression-free interval). Receiver-operating characteristic (ROC) curves showed that BATF had excellent diagnostic value in KIRC, as evidenced by the AUC and cutoff values of 0.942 and 2.033, respectively. Kaplan-Meier survival curves demonstrated that KIRC patients with high-BATF were associated with worse prognosis (hazard ratio =1.42, P=0.024). Results from Cox univariate analyses indicated that BATF was an independent prognostic factor in KIRC patients, and survival probabilities were predicted by the established nomogram. Results from the Tumor Immune Estimation Resource (TIMER) and BATF mRNA expression showed an association with immune cell infiltration. Conclusions: BATF is a prognostic biomarker and a potential target for immune therapies in KIRC.

Transcriptomic and metabolomic analyses reveal the mechanism of uniconazole inducing hypocotyl dwarfing by suppressing BrbZIP39-BrPAL4 module mediating lignin biosynthesis in flowering Chinese cabbage.

Uniconazole, a triazole plant growth regulator, is widely used to regulate plant height and prevent the overgrowth of seedlings. However, the underlying molecular mechanism of uniconazole in inhibiting the hypocotyl elongation of seedlings is still largely unclear, and there has been little research on the integration of transcriptomic and metabolomic data to investigate the mechanisms of hypocotyl elonga-tion. Herein we observed that the hypocotyl elongation of flowering Chinese cabbage seedings was significantly inhibited by uniconazole. Interestingly, based on combined transcriptome and metabolome analyses, we found that the "phenylpropanoid biosynthesis" pathway was significantly affected by uniconazole. In this pathway, only one member of the portal enzyme gene family, named BrPAL4, was remarkably downregulated, which was related to lignin biosynthesis. Furthermore, the yeast one-hybrid and dual-luciferase assays showed that BrbZIP39 could directly bind to the promoter region of BrPAL4 and activate its transcript. The virus-induced gene silencing system further demonstrated that BrbZIP39 could positively regulate hypocotyl elongation and the lignin biosynthesis of hypocotyl. Our findings provide a novel insight into the molecular regulatory mechanism of uniconazole inhibiting hypocotyl elongation in flowering Chinese cabbage and confirm, for the first time, that uniconazole decreases lignin content through repressing the BrbZIP39-BrPAL4 module-mediated phenylpropanoid biosynthesis, which leads to the hypocotyl dwarfing of flowering Chinese cabbage seedlings.

IRF8 and BATF3 interaction enhances the cDC1 specific Pfkfb3 gene expression.

Dendritic cells (DCs) play central role in innate as well as adaptive immune responses regulated by diverse DC subtypes that vary in terms of surface markers, transcriptional profile and functional responses. Generation of DC diversity from progenitor stage is tightly regulated by complex molecular inter-play between transcription factors. We earlier demonstrated that Batf3 and Id2 expression have a synergistic effect on the Irf8 directed classical cDC1 development. In present study, Bi-molecular fluorescence complementation assay suggested that IRF8 interacts with BATF3, and ID2 may aid cDC1 development independently. Genome wide recruitment analysis of IRF8 and BATF3 from different DC subtypes led to identification of the overlapping regions of occupancy by these two transcription factors. Further analysis of overlapping peaks of IRF8 and BATF3 occupancy in promoter region within the cDC1 subtype specific transcriptional pattern identified a metabolically important Pfkfb3 gene. Among various immune cell types; splenic cDC1 subtype displayed enhanced expression of Pfkfb3. Analysis of Irf8-/-, Irf8R294C and Batf3DCKO DC confirmed direct regulation of Pfkfb3 enhanced expression specifically in cDC1 subtype. Further we show that inhibition of PFKFB3 enzymatic activity by a chemical agent PFK15 led to reduction in cDC1 subtype in both in vitro FLDC cultures as well as in vivo mouse spleens. Together, our study identified the direct regulation of cDC1 specific enhanced expression of Pfkfb3 in glycolysis and cDC1 biology.

Diagnostic and Prognostic Potential of Circulating and Tissue BATF2 in Nasopharyngeal Carcinoma.

Background: Current biomarkers for nasopharyngeal carcinoma (NPC) are less effective for early diagnosis and prognosis. The basic leucine zipper ATF-like transcription factor 2 (BATF2) gene has been shown to have a tight association with the pathogenesis of various malignancies but received scant attention in NPC research. We aimed to assess the performances of circulating and tissue BATF2 in the diagnosis and prognosis of NPC. Materials and Methods: Immunohistochemistry (IHC) microarrays were performed to quantitate the BATF2 protein expression in NPC tissues. The relationships of BATF2 protein expression with clinicopathological characteristics and NPC prognosis were assessed. BATF2 mRNA expressions in serum and serum-derived exosomes were determined using quantitative reverse transcription-polymerase chain reaction (qRT-PCR) assay. Results: The IHC microarrays revealed a predominant nuclear expression of BATF2 in NPC cells. The Kaplan-Meier survival analysis showed that BATF2-positive NPC patients enjoyed longer overall survival than BATF2-negative patients. NPC patients with serum and exosomal BATF2 mRNA expressions made up 51.47 and 48.52% of all patients, respectively. The AUCs of serum and exosomal BATF2 mRNA expressions in discriminating NPC from healthy controls were 0.9409 and 0.8983. Patients who had received radiochemotherapy exhibited higher serum and exosomal BATF2 mRNA expressions versus the levels at baseline as well as those detected in recurrent patients. Conclusion: BATF2 is expressed cancerous tissues, serum, and serum-derived exosomes in NPC patients. Circulating and tissue BATF2 can serve as a multipurpose biomarker capable of the diagnosis, prognosis prediction, efficacy evaluation, and recurrence monitoring in NPC.

Heme oxygenase-1 induction by heat shock in rat hepatoma cell line is regulated by the coordinated function of HSF1, NRF2 and BACH1.

The mechanism of heme oxygenase-1 (HO-1) induction by heat shock (HS) loading remains unclear. Here, we investigated the contribution of transcription factors to HS-induced HO-1 expression, using a rat hepatoma cell line (H-4-II-E). Our results demonstrated that HS treatment resulted in a marked induction of HO-1. Immunohistochemical analysis showed a slight mismatch in the expression levels of HO-1 and HSP70 by HS among cells, suggesting a conflict between multiple induction mechanisms. We observed HS-induced nuclear localization of, not only phosphorylated HSF1 but also NRF2, which is a typical transcription factor activated by oxidative stress. HSF1 knockdown in H-4-II-E markedly reduced HO-1 induction by HS, while NRF2 knockdown resulted in a partial effect. The chromatin immunoprecipitation assay demonstrated that HS loading resulted in significant binding of HSF1 to the HSE in the promoter proximal region of HO-1 gene and another HSE located close to the Maf recognition element (MARE) in the -4 kb upstream enhancer region 1, where NRF2 also bound, together with basic leucine zipper transcription factor 1, a negative transcription factor of HO-1. These observations indicate that HO-1 induction by HS is mainly mediated by HSF1 binding to the proximal HSE. NRF2 binding to MARE by HS is predominantly suppressed by an increased binding of BACH1.

Genome-wide identification of bZIP transcription factor genes related to starch synthesis in barley (Hordeum vulgare L.).

The basic leucine zipper (bZIP) family of genes encode transcription factors that play key roles in plant growth and development. In this study, a total of 92 HvbZIP genes were identified and compared with previous studies using recently released barley genome data. Two novel genes were characterized in this study, and some misannotated and duplicated genes from previous studies have been corrected. Phylogenetic analysis results showed that 92 HvbZIP genes were classified into 10 groups and three unknown groups. The gene structure and motif distribution of the three unknown groups implied that the genes of the three groups may be functionally different. Expression profiling indicated that the HvbZIP genes exhibited different patterns of spatial and temporal expression. Using qRT-PCR, more than 10 HvbZIP genes were identified with expression patterns similar to those of starch synthase genes in barley. Yeast one-hybrid analysis revealed that two of the HvbZIP genes exhibited in vitro binding activity to the promoter of HvAGP-S. The two HvbZIP genes may be candidate genes for further study to explore the mechanism by which they regulate the synthesis of barley starch.

Structure and function of the vacuolar Ccc1/VIT1 family of iron transporters and its regulation in fungi.

Iron is an essential micronutrient for most living beings since it participates as a redox active cofactor in many biological processes including cellular respiration, lipid biosynthesis, DNA replication and repair, and ribosome biogenesis and recycling. However, when present in excess, iron can participate in Fenton reactions and generate reactive oxygen species that damage cells at the level of proteins, lipids and nucleic acids. Organisms have developed different molecular strategies to protect themselves against the harmful effects of high concentrations of iron. In the case of fungi and plants, detoxification mainly occurs by importing cytosolic iron into the vacuole through the Ccc1/VIT1 iron transporter. New sequenced genomes and bioinformatic tools are facilitating the functional characterization, evolution and ecological relevance of metabolic pathways and homeostatic networks across the Tree of Life. Sequence analysis shows that Ccc1/VIT1 homologs are widely distributed among organisms with the exception of animals. The recent elucidation of the crystal structure of a Ccc1/VIT1 plant ortholog has enabled the identification of both conserved and species-specific motifs required for its metal transport mechanism. Moreover, recent studies in the yeast Saccharomyces cerevisiae have also revealed that multiple transcription factors including Yap5 and Msn2/Msn4 contribute to the expression of CCC1 in high-iron conditions. Interestingly, Malaysian S. cerevisiae strains express a partially functional Ccc1 protein that renders them sensitive to iron. Different regulatory mechanisms have been described for non-Saccharomycetaceae Ccc1 homologs. The characterization of Ccc1/VIT1 proteins is of high interest in the development of biofortified crops and the protection against microbial-derived diseases.