Subfamily Of Transcription Factors Research Articles

Fingerprint-based similarity search identified p-anisidine as an anticancer agent in HeLa and a prospective phytochemical ETV1 transcription factor inhibitor

Overexpression of E26 transformation-specific (ETS) PEA3 subfamily transcription factor (TF) ETV1 is reportedly oncogenic and metastatic in several cancers. Albeit, a few synthetic small molecule inhibitors of ETV1 have been identified to date. In this context, we hereby proposed a phytochemical lead development scheme to gather inhibitor scaffolds for ETV1. A fingerprint-based similarity search was conducted to screen plant compounds structurally similar to known ETV1 perturbagens. At default cutoffs, 20 compounds were retrieved whose pharmacokinetic, docking, and scaffold analysis rendered eight compounds for final evaluation in HeLa cells by MTT assay. CID7732 (p-anisidine) belonging to the subclass aminophenyl ethers was emerged as a promising anticancer agent with an IC50 of 27.769 µg/mL. This is the first natural product-based chemical hunt carried out for ETV1 repressors. Communicated by Ramaswamy H. Sarma

Phylogenomic analysis of the APETALA2 transcription factor subfamily across angiosperms reveals both deep conservation and lineage-specific patterns.

SummaryThe APETALA2 (AP2) subfamily of transcription factors are key regulators of angiosperm root, shoot, flower and embryo development. The broad diversity of anatomical and morphological structures is potentially associated with the genomic dynamics of the AP2 subfamily. However, a comprehensive phylogenomic analysis of the AP2 subfamily across angiosperms is lacking. We combined phylogenetic and synteny analysis of distinct AP2 subclades in the completed genomes of 107 angiosperm species. We identified major changes in copy number variation and genomic context within subclades across lineages, and discuss how these changes may have contributed to the evolution of lineage‐specific traits. Multiple AP2 subclades show highly conserved patterns of copy number and synteny across angiosperms, while others are more dynamic and show distinct lineage‐specific patterns. As examples of lineage‐specific morphological divergence due to AP2 subclade dynamics, we hypothesize that loss of PLETHORA1/2 in monocots correlates with the absence of taproots, whereas independent lineage‐specific changes of PLETHORA4/BABY BOOM and WRINKLED1 genes in Brassicaceae and monocots point towards regulatory divergence of embryogenesis between these lineages. Additionally, copy number expansion of TOE1 and TOE3/AP2 in asterids is implicated with differential regulation of flower development. Moreover, we show that the genomic context of AP2s is in general highly specialized per angiosperm lineage. To our knowledge, this study is the first to shed light on the evolutionary divergence of the AP2 subfamily subclades across major angiosperm lineages and emphasizes the need for lineage‐specific characterization of developmental networks to understand trait variability further.

Specificity, redundancy and dosage thresholds among gata4/5/6 genes during zebrafish cardiogenesis.

ABSTRACTThe Gata4/5/6 sub-family of zinc finger transcription factors regulate many aspects of cardiogenesis. However, critical roles in extra-embryonic endoderm also challenge comprehensive analysis during early mouse cardiogenesis, while zebrafish models have previously relied on knockdown assays. We generated targeted deletions to disrupt each gata4/5/6 gene in zebrafish and analyzed cardiac phenotypes in single, double and triple mutants. The analysis confirmed that loss of gata5 causes cardia bifida and validated functional redundancies for gata5/6 in cardiac precursor specification. Surprisingly, we discovered that gata4 is dispensable for early zebrafish development, while loss of one gata4 allele can suppress the bifid phenotype of the gata5 mutant. The gata4 mutants eventually develop an age-dependent cardiomyopathy. By combining combinations of mutant alleles, we show that cardiac specification depends primarily on an overall dosage of gata4/5/6 alleles rather than a specific gene. We also identify a specific role for gata6 in controlling ventricle morphogenesis through regulation of both the first and second heart field, while loss of both gata4/6 eliminates the ventricle. Thus, different developmental programs are dependent on total dosage, certain pairs, or specific gata4/5/6 genes during embryonic cardiogenesis.This article has an associated First Person interview with the first author of the paper.

The HD-ZIP II Transcription Factors Regulate Plant Architecture through the Auxin Pathway.

The homeodomain-leucine zipper (HD-ZIP) family transcription factors play important roles in plant growth and development. However, the underlying mechanisms remain largely unclear. Here we found that ATHB2, encoding a HD-ZIP transcription factor, is an early auxin responsive gene. Phenotypic analyses show that overexpression of ATHB2 impairs plant architecture, including reduced plant height and small leaves, and also reduces auxin response in leaves when grown in soil. Simultaneously, the seedlings with chemical induction of ATHB2 exhibit abnormal root gravitropism, a typical auxin-related phenotype. We further show that the auxin response pattern is altered in roots of the inducible ATHB2 seedlings. Consistently, the transcript levels of some auxin biosynthetic and transport genes are significantly decreased in these transgenic seedlings. Further, protein and promoter sequence analyses in common wheat showed that the HD-ZIP II subfamily transcription factors have highly conserved motifs and most of these encoding gene promoters contain the canonical auxin-responsive elements. Expression analyses confirm that some of these HD-ZIP II genes are indeed regulated by auxin in wheat. Together, our results suggest that the HD-ZIP II subfamily transcription factors regulate plant development possibly through the auxin pathway in plants.

Ectopic expression of HaNAC1, an ATAF transcription factor from Haloxylon ammodendron, improves growth and drought tolerance in transgenic Arabidopsis

NAC transcription factors play a pivotal role in plant growth, development and response to abiotic stress. However, their biological functions in desert trees are largely unknown. In this work, the NAC transcription factor HaNAC1 from Haloxylon ammodendron, a typical wooden plant normally grown in desert, was isolated, and its possible role in plant growth and resistance to drought stress was investigated. HaNAC1 encodes an ATAF subfamily transcription factor containing one NAC domain with five conserved regions. Quantitative real time PCR analyses revealed that HaNAC1 was ubiquitously expressed in various tissues and organs such as roots, stems, leaves and seeds, with a predominant expression in stems. Further studies demonstrated that expression of HaNAC1 was significantly induced by osmotic stress in Haloxylon ammodendron seedlings, and subcellular localization analysis indicated that GFP-HaNAC1 fusion protein was localized to the nucleus in Arabidopsis leaf protoplast. Ectopic expression of HaNAC1 led to promoted growth and drought tolerance in transgenic Arabidopsis, accompanied with up-regulated expression of stress-inducible marker genes, and increased accumulation of proline, IAA and ABA under both normal and drought stress conditions. In addition, co-immunoprecipitation and Bi-molecular fluorescence complementation assays illustrated that HaNAC1 directly interacted with AtNAC32. All these results suggest that HaNAC1 is involved in both the growth and drought resistance of Haloxylon ammodendron, and could be used as a promising candidate gene for the breeding of crops with augmented tolerance to drought stress.

Androgen up-regulation of Twist1 gene expression is mediated by ETV1.

Twist1, a basic helix-loop-helix transcription factor that regulates a number of genes involved in epithelial-to-mesenchymal transition (EMT), is upregulated in prostate cancer. Androgen regulation of Twist1 has been reported in a previous study. However, the mechanism of androgen regulation of the Twist1 gene is not understood because the Twist1 promoter lacks androgen receptor (AR)-responsive elements. Previous studies have shown that the Twist1 promoter has putative binding sites for PEA3 subfamily of ETS transcription factors. Our lab has previously identified Ets Variant 1 (ETV1), a member of the PEA3 subfamily, as a novel androgen-regulated gene that is involved in prostate cancer cell invasion through unknown mechanism. In view of these data, we hypothesized that androgen-activated AR upregulates Twist1 gene expression via ETV1. Our data confirmed the published work that androgen positively regulates Twist1 gene expression and further showed that this positive effect was directed at the Twist1 promoter. The positive effect of androgen on Twist1 gene expression was abrogated upon disruption of AR expression by siRNA or of AR activity by Casodex. More importantly, our data show that disruption of ETV1 leads to significant decrease in both androgen-mediated upregulation as well as basal level of Twist1, which we are able to rescue upon re-expression of ETV1. Indeed, we are able to show that ETV1 mediates the androgen upregulation of Twist1 by acting on the proximal region of Twist1 promoter. Additionally, our data show that Twist1 regulates prostate cancer cell invasion and EMT, providing a possible mechanism by which ETV1 mediates prostate cancer cell invasion. In conclusion, in this study we report Twist1 as an indirect target of AR and androgen regulation through ETV1.

Revisiting floral fusion: the evolution and molecular basis of a developmental innovation.

Throughout the evolution of the angiosperm flower, developmental innovations have enabled the modification or elaboration of novel floral organs enabling subsequent diversification and expansion into new niches, for example the formation of novel pollinator relationships. One such developmental innovation is the fusion of various floral organs to form complex structures. Multiple types of floral fusion exist; each type may be the result of different developmental processes and is likely to have evolved multiple times independently across the angiosperm tree of life. The development of fused organs is thought to be mediated by the NAM/CUC3 subfamily of NAC transcription factors, which mediate boundary formation during meristematic development. The goal of this review is to (i) introduce the development of fused floral organs as a key 'developmental innovation', facilitated by a change in the expression of NAM/CUC3 transcription factors; (ii) provide a comprehensive overview of floral fusion phenotypes amongst the angiosperms, defining well-known fusion phenotypes and applying them to a systematic context; and (iii) summarize the current molecular knowledge of this phenomenon, highlighting the evolution of the NAM/CUC3 subfamily of transcription factors implicated in the development of fused organs. The need for a network-based analysis of fusion is discussed, and a gene regulatory network responsible for directing fusion is proposed to guide future research in this area.

Two promoter regions confer heat-induced activation of SlDREBA4 in Solanum lycopersicum

Dehydration-responsive element binding (DREB) transcription factors activate the expression of downstream functional genes in combination with a dehydration-responsive element (DRE), and thereby improve the resistance of plants to abiotic stresses such as heat. However, the upstream regulatory mechanism of DREB genes under heat is unclear. A DREBA4 subfamily transcription factor (SlDREBA4), which is heat-responsive and improves heat resistance, was isolated from Solanum lycopersicum ‘Microtom’. In this study, promoter truncation experiments were performed to verify changes in β-glucuronidase (GUS) enzyme activity and GUS gene expression levels in transgenic plants with different lengths of promoter fragments under heat and to identify specific regions in the promoter that respond to heat. Our results showed that the GUS reporter gene was constitutively expressed in tissues of the full-length promoter transgenic ‘Microtom’ plants, with higher expression in conducting tissues of root, stem, and leaf, as well as sepals of flowers and fruits. Under heat treatment, GUS enzyme activity and GUS gene expression levels in tissues of the full-length promoter transgenic plants increased. Promoter deletion analysis identified two positive regulatory regions (−1095 to −730 bp and −162 to −38 bp) responsible for the promoter’s response to heat. These results indicated that the heat shock element (HSE) and MYC recognition sequences may cooperate in heat-induced activation of SlDREBA4 promoter.

Besides and Beyond Flowering: Other roles of EuAP2 Genes in Plant Development.

EuAP2 genes are well-known for their role in flower development, a legacy of the founding member of this subfamily of transcription factors, whose mutants lacked petals in Arabidopsis. However, studies of euAP2 genes in several species have accumulated evidence highlighting the diverse roles of euAP2 genes in other aspects of plant development. Here, we emphasize other developmental roles of euAP2 genes in various species and suggest a shift from regarding euAP2 genes as just flowering genes to consider the global role they may be playing in plant development. We hypothesize that their almost universal expression profile and pleiotropic effects of their mutation suggest their involvement in fundamental plant development processes.

Differential Control of iNKT Cell Effector Lineage Differentiation by the Forkhead Box Protein O1 (Foxo1) Transcription Factor.

The invariant NKT (iNKT) cells recognize glycolipid antigens presented by the non-classical MHC like molecule CD1d. They represent an innate T-cell lineage with the ability to rapidly produce a variety of cytokines in response to agonist stimulation to bridge innate and adaptive immunity. In thymus, most iNKT cells complete their maturation and differentiate to multiple effector lineages such as iNKT-1, iNKT-2, and iNKT-17 cells that possess the capability to produce IFNγ, IL-4, and IL-17A, respectively, and play distinct roles in immune responses and diseases. Mechanisms that control iNKT lineage fate decisions are still not well understood. Evidence has revealed critical roles of Foxo1 of the forkhead box O1 subfamily of transcription factors in the immune system. However, its role in iNKT cells has been unknown. In this report, we demonstrate that deletion of Foxo1 causes severe decreases of iNKT cell total numbers due to impairment of late but not early iNKT cell development. Deficiency of Foxo1 results in decreases of iNKT-1 but increases of iNKT-17 cells. Our data reveal that Foxo1 controls iNKT effector lineage fate decision by promoting iNKT-1 but suppressing iNKT-17 lineages.

ETV4 overexpression promotes progression of non-small cell lung cancer by upregulating PXN and MMP1 transcriptionally.

ETS variant 4 (ETV4), together with ETV1 and ETV5, constitute the PEA3 subfamily of ETS transcription factors, which are implicated in the progression of many cancers. However, the clinicopathologic significance and molecular events regulated by ETV4 in lung cancer are still poorly understood, especially in squamous cell carcinoma of the lung. Here, we aimed to identify functional targets involved in ETV4-driven lung tumorigenesis. Microarray analysis and validation data revealed that ETV4 was the most preponderant PEA3 factor, which was significantly related to the advanced stage, lymph node metastasis, and poor prognosis of non-small cell lung cancers (NSCLCs; all P < .001). Reduced ETV4 expression suppressed the growth and metastasis of NSCLC both in vivo and in vitro. Microarray, gain, or loss of function and luciferase report assays revealed the direct regulatory effect of ETV4 on the expression of focal adhesion gene PXN and matrix metalloproteinase 1 (MMP1), and PXN and/or MMP1 inhibition partially abolished cell proliferation and migration induced by ETV4. Kaplan-Meier analysis indicated that ETV4 and PXN or MMP1 co-overexpression is associated with poor prognosis in human NSCLCs. In conclusion, the ETV4-PXN and ETV4-MMP1 axes are useful biomarkers of tumor progression and worse outcomes in NSCLCs.

Constitutive expression of an A-5 subgroup member in the DREB transcription factor subfamily from Ammopiptanthus mongolicus enhanced abiotic stress tolerance and anthocyanin accumulation in transgenic Arabidopsis.

Dehydration-responsive element-binding (DREB) transcription factors (TFs) are key regulators of stress-inducible gene expression in plants. Anthocyanins, an important class of flavonoids, protect plants from reactive oxygen species produced under abiotic stresses. However, regulation of DREBs on anthocyanin accumulation is largely unknown. Here, an A-5 subgroup DREB gene (AmDREB3) isolated from Ammopiptanthus mongolicus, a desert broadleaf shrub with very high tolerance to harsh environments, was characterized in terms of both abiotic stress tolerance and anthocyanin accumulation. AmDREB3 does not contain the transcriptional repression motif EAR, and the protein was located in the nucleus and has transcriptional activation capacity. The transcription of AmDREB3 was differentially induced in the shoots and roots of A. mongolicus seedlings under drought, salt, heat, cold, ultraviolet B, and abscisic acid treatments. Moreover, the transcript levels in twigs, young leaves, and roots were higher than in other organs of A. mongolicus shrubs. Constitutively expressing AmDREB3 improved the tolerance of transgenic Arabidopsis to drought, high salinity and heat, likely by inducing the expression of certain stress-inducible genes. The transgenic Arabidopsis seedlings also exhibited an obvious purple coloration and significant increases in anthocyanin accumulation and/or oxidative stress tolerance under drought, salt, and heat stresses. These results suggest that the AmDREB3 TF may be an important positive regulator of both stress tolerance and anthocyanin accumulation.

Divergent Functional Diversification Patterns in the SEP/AGL6/AP1 MADS-Box Transcription Factor Superclade.

Members of SEPALLATA (SEP) and APETALA1 (AP1)/SQUAMOSA (SQUA) MADS-box transcription factor subfamilies play key roles in floral organ identity determination and floral meristem determinacy in the rosid species Arabidopsis (Arabidopsis thaliana). Here, we present a functional characterization of the seven SEP/AGL6 and four AP1/SQUA genes in the distant asterid species petunia (Petunia × hybrida). Based on the analysis of single and higher order mutants, we report that the petunia SEP1/SEP2/SEP3 orthologs together with AGL6 encode classical SEP floral organ identity and floral termination functions, with a master role for the petunia SEP3 ortholog FLORAL BINDING PROTEIN2 (FBP2). By contrast, the FBP9 subclade members FBP9 and FBP23, for which no clear ortholog is present in Arabidopsis, play a major role in determining floral meristem identity together with FBP4, while contributing only moderately to floral organ identity. In turn, the four members of the petunia AP1/SQUA subfamily redundantly are required for inflorescence meristem identity and act as B-function repressors in the first floral whorl, together with BEN/ROB genes. Overall, these data together with studies in other species suggest major differences in the functional diversification of the SEP/AGL6 and AP1/SQUA MADS-box subfamilies during angiosperm evolution.plantcell;31/12/3033/FX1F1fx1.

Transcriptional profiling of the AFL subfamily of B3-type transcription factors during the in vitro induction of somatic embryogenesis in the model legume Medicago truncatula

In many legume species, somatic embryogenesis is a limiting step of in vitro regeneration, with profound implications to genetic engineering and plant breeding. In Arabidopsis thaliana, the small AFL subfamily of B3-type transcriptional factors is composed by LEC2 (LEAFY COTYLEDON 2), FUSCA (FUSCA3), and ABI3 (ABSCISIC ACID INSENSITIVE 3), which are directly involved in both zygotic and somatic embryogenesis. This study aimed to identify and analyze the expression profile of AFL subfamily genes during in vitro induction of the somatic embryogenesis in the model legume Medicago using near-isogenic genotypes contrasting for their capability of regenerating in vitro. Three AFL genes were identified in the Medicago truncatula genome: MtLEC2, MtFUSCA3 and MtABI3. RT-qPCR was used to compare the expression of these genes during the induction of somatic embryogenesis in the embryogenic genotype M9-10a and the non-embryogenic genotype M9. The AFL genes identified were highly expressed 10 days after introducing leaflet explants in vitro in the embryogenic genotype (M9-10a), whereas absence or low expression was observed in explants of the non-embryogenic genotype (M9). During zygotic embryogenesis, the Medicago Gene Atlas revealed that expression of MtFUSCA3 and MtABI3 occurred specifically during seed development, starting at 10 days after pollination. This study allowed for the identification and transcriptional characterization of MtLEC2, MtFUSCA3, and MtABI3. The expression pattern of these genes in the M9-10a genotype suggests they are involved in the Medicago truncatula somatic embryogenesis. The transcriptional profile of AFL transcription factors highlights the evolutionary conservation of this developmental pathway between the Arabidopsis and Medicago lineages and opens avenues to improve the efficiency of in vitro embryogenesis in legume crops. Expression of MtLEC2, MtFUSCA3, and MtABI3 genes was induced during somatic embryogenesis and these genes to be used as in vitro regeneration biomarkers as well as to improving somatic embryogenic rates in legumes and other crops recalcitrant to in vitro regeneration.

SOX4: Epigenetic regulation and role in tumorigenesis.

Sex-determining region Y-related (SRY) high-mobility group box 4 (SOX4) is a member of the group C subfamily of SOX transcription factors and promotes tumorigenesis by endowing cancer cells with survival, migratory, and invasive capacities. Emerging evidence has highlighted an unequivocal role for this transcription factor in mediating various signaling pathways involved in tumorigenesis, epithelial-to-mesenchymal transition (EMT), and tumor progression. During the last decade, numerous studies have highlighted the epigenetic interplay between SOX4-targeting microRNAs (miRNAs), long noncoding RNAs (lncRNAs) and SOX4 and the subsequent modulation of tumorigenesis, invasion and metastasis. In this review, we summarize the current state of knowledge about the role of SOX4 in cancer development and progression, the epigenetic regulation of SOX4, and the potential utilization of SOX4 as a diagnostic and prognostic biomarker and its depletion as a therapeutic target.

Identification, Structural and Functional Characterization of Dormancy Regulator Genes in Apricot (Prunus armeniaca L.).

In the present study, we identified and characterized the apricot (Prunus armeniaca L.) homologs of three dormancy-related genes, namely the ParCBF1 (C-repeat binding factor), ParDAM5 (dormancy-associated MADS-BOX) and ParDAM6 genes. All highly conserved structural motifs and the 3D model of the DNA-binding domain indicate an unimpaired DNA-binding ability of ParCBF1. A phylogenetic analysis showed that ParCBF1 was most likely homologous to Prunus mume and Prunus dulcis CBF1. ParDAM5 also contained all characteristic domains of the type II (MIKCC) subfamily of MADS-box transcription factors. The homology modeling of protein domains and a phylogenetic analysis of ParDAM5 suggest its functional integrity. The amino acid positions or small motifs that are diagnostic characteristics of DAM5 and DAM6 were determined. For ParDAM6, only a small part of the cDNA was sequenced, which was sufficient for the quantification of gene expression. The expression of ParCBF1 showed close association with decreasing ambient temperatures in autumn and winter. The expression levels of ParDAM5 and ParDAM6 changed according to CBF1 expression rates and the fulfillment of cultivar chilling requirements (CR). The concomitant decrease of gene expression with endodormancy release is consistent with a role of ParDAM5 and ParDAM6 genes in dormancy induction and maintenance. Cultivars with higher CR and delayed flowering time showed higher expression levels of ParDAM5 and ParDAM6 toward the end of endodormancy. Differences in the timing of anther developmental stages between early- and late-flowering cultivars and two dormant seasons confirmed the genetically and environmentally controlled mechanisms of dormancy release in apricot generative buds. These results support that the newly identified apricot gene homologs have a crucial role in dormancy-associated physiological mechanisms.

DMBX1 promotes tumor proliferation and regulates cell cycle progression via repressing OTX2-mediated transcription of p21 in lung adenocarcinoma cell.

Lung adenocarcinoma (LUAD) was the predominant histological subtype of lung cancer, with poor prognosis. By analyzing the TCGA dataset, we found that DMBX1 (diencephalon/mesencephalon homeobox 1), a member of the bicoid sub-family of homeodomain-containing transcription factors, was overexpressed in LUAD and correlated with poorer prognosis and more advanced clinicopathological features of LUAD patients. Silencing of DMBX1 inhibited proliferation of LUAD and induced G1/S cell cycle arrest, whereas ectopic expression of DMBX1 enhanced tumor growth of LUAD and promoted G1/S cell cycle exit. Furtherly we found that the function of DMBX1 was dependent on p21 (CDKN1A), a key regulator of G1/S cell cycle progression. Co-IP assay revealed that DMBX1 directly bound to another homeobox transcription factor, OTX2. ChIP and luciferase reporter assay confirmed that OTX2 directly interacted with the promoter region of p21 to enhance its transcription, and DMBX1 repressed OTX2-mediated transcription of p21. Our study reveals that DMBX1 plays an oncogenic role in LUAD by repressing OTX2-mediated transcription of p21 and the results may provide new therapeutic targets for LUAD patients.

Epigenetic Suppression of the T-box Subfamily 2 (TBX2) in Human Non-Small Cell Lung Cancer.

(1) The TBX2 subfamily of transcription factors (TBXs 2, 3, 4 and 5) are markedly down-regulated in human non-small cell lung cancer (NSCLC) and exert tumor suppressor effects in lung malignancy. Yet, mechanisms underlying suppressed expression of the TBX2 subfamily in NSCLC are elusive. Here, we interrogated probable epigenetic mechanisms in suppressed expression of the TBX2 subfamily in human NSCLC. (2) TBX2 subfamily gene expression and methylation levels in NSCLC and normal lung tissues were surveyed using publicly available RNA-sequence and genome-wide methylation datasets. Methylation β-values of the four genes were statistically compared between NSCLCs and normal lung tissues, correlated with gene expression levels, and interrogated with clinicopathological variables. Expression and methylation levels of TBXs were quantified in NSCLC cells using real-time PCR and methylation-specific PCR assays, respectively. Effects of the DNA methyltransferase inhibitor 5-azacytidine (Aza) on TBX2 subfamily expression were assessed in NSCLC cells. Impact of TBX2 subfamily expression on Aza-treated cells was evaluated by RNA interference. (3) All four TBXs were significantly hypermethylated in NSCLCs relative to normal lung tissues (p < 0.05). Methylation β-values of the genes, with exception of TBX2, were significantly inversely correlated with corresponding mRNA expression levels (p < 0.05). We found no statistically significant differences in hypermethylation levels of the TBX2 subfamily by clinicopathological features including stage and tobacco history. Expression levels of the TBX genes were overall suppressed in NSCLC cells relative to normal alveolar cells. Members of the subfamily were significantly hypermethylated in all tested NSCLC cell lines relative to normal alveolar cells. Treatment with Aza induced the expression of the TBX2 subfamily concomitant with NSCLC cell growth inhibition. Further, simultaneous knockdown of the four TBX genes markedly reduced anti-growth effects of Aza in NSCLC cells. (4) Our study sheds light on new epigenetic profiles in the molecular pathogenesis of human NSCLC.

Ectopic expression of the AaFUL1 gene identified in Anthurium andraeanum affected floral organ development and seed fertility in tobacco

Anthurium andraeanum is a high-grade potted flower that enjoys global popularity. Its floral organs have been substantially modified, and its ornamental value is based on its petaloid bracts. MADS-box gene products are important transcription factors that control plant development. In particular, the APETALA1 (AP1)/FRUITFULL (FUL) family of MADS-box genes plays a key role in flowering transitions and out-whorl floral organ identity specification. In this report, one FUL-like gene was cloned from Anthurium andraeanum and named AaFUL1 after bioinformatics identification. Subsequent subcellular localization experiments confirmed that the AaFUL1 protein was located in the nucleus, and data obtained from an expression analysis indicated that the relative expression level of AaFUL1 was the highest in bracts and inflorescences, while its expression was relatively low in stems and roots. Next, an AaFUL1 overexpression vector was constructed and ectopically expressed in tobacco. The transformants did not show any early flowering phenotype, but the average internode length of the inflorescence branch was significantly higher than that observed in the control, and its petal color had substantially faded. The morphology of the petal and pistil was clearly changed, the fruit was deformed, and the seed was largely aborted. These data indicate that even though the sequence of AaFUL1 is relatively conserved, its function differs from that of other orthologs, and the FUL subfamily of MADS-box transcription factors may have taken on new functions during the evolution processes. The results of this experiment enrich our knowledge of FUL transcription factors in monocotyledon plants.

Insights from the crystal structure of the chicken CREB3 bZIP suggest that members of the CREB3 subfamily transcription factors may be activated in response to oxidative stress

cAMP response element binding Protein 3 (CREB3) is an endoplasmic reticulum (ER) membrane‐bound transcription factor, which belongs to the basic leucine zipper (bZIP) superfamily of eukaryotic transcription factors. CREB3 plays a role in the ER‐stress induced unfolded protein response (UPR) and is a multifunctional cellular factor implicated in a number of biological processes including cell proliferation and migration, tumor suppression, and immune‐related gene expression. To gain structural insights into the transcription factor, we determined the crystal structure of the conserved bZIP domain of chicken CREB3 (chCREB3) to a resolution of 3.95 Å. The X‐ray structure provides evidence that chCREB3 can form a stable homodimer. The chCREB3 bZIP has a structured, pre‐formed DNA binding region, even in the absence of DNA, a feature that could potentially enhance both the DNA binding specificity and affinity of chCREB3. Significantly, the homodimeric bZIP possesses an intermolecular disulfide bond that connects equivalent cysteine residues of the parallel helices in the leucine zipper region. This disulfide bond in the hydrophobic core of the bZIP may increase the stability of the homodimer under oxidizing conditions. Moreover, sequence alignment of bZIP sequences from chicken, human, and mouse reveals that only members of the CREB3 subfamily contain this cysteine residue, indicating that it could act as a redox‐sensor. Taken together, these results suggest that the activity of these transcription factors may be redox‐regulated and they may be activated in response to oxidative stress.