Universal Transcription Factor Research Articles

Bacteroides expand the functional versatility of a universal transcription factor and transcribed DNA to program capsule diversity.

Human gut Bacteroides species encode numerous (eight or more) tightly regulated capsular polysaccharides (CPS). Specialized paralogs of the universal transcription elongation factor NusG, called UpxY (Y), and an anti-Y UpxZ (Z) are encoded by the first two genes of each CPS operon. The Y-Z regulators combine with promoter inversions to limit CPS transcription to a single operon in most cells. Y enhances transcript elongation whereas Z inhibits noncognate Ys. How Y distinguishes among cognate CPS operons and how Z inhibits only noncognate Ys are unknown. Using in-vivo nascent-RNA sequencing and p romoter-less in v itr o transcription (PIVoT), we establish that Y recognizes a paused RNA polymerase via sequences in both the exposed non-template DNA and the upstream duplex DNA. Y association is aided by novel 'pause-then-escape' nascent RNA hairpins. Z binds non-cognate Ys to directly inhibit Y association. This Y-Z hierarchical regulatory program allows Bacteroides to create CPS subpopulations for optimal fitness.

Key interactions of RNA polymerase with 6S RNA and secondary channel factors during pRNA synthesis

Small non-coding 6S RNA mimics DNA promoters and binds to the σ70 holoenzyme of bacterial RNA polymerase (RNAP) to suppress transcription of various genes mainly during the stationary phase of cell growth or starvation. This inhibition can be relieved upon synthesis of short product RNA (pRNA) performed by RNAP from the 6S RNA template. Here, we have shown that pRNA synthesis depends on specific contacts of 6S RNA with RNAP and interactions of the σ finger with the RNA template in the active site of RNAP, and is also modulated by the secondary channel factors. We have adapted a molecular beacon assay with fluorescently labeled σ70 to analyze 6S RNA release during pRNA synthesis. We found the kinetics of 6S RNA release to be oppositely affected by mutations in the σ finger and in the CRE pocket of core RNAP, similarly to the reported role of these regions in promoter-dependent transcription. Secondary channel factors, DksA and GreB, inhibit pRNA synthesis and 6S RNA release from RNAP, suggesting that they may contribute to the 6S RNA-mediated switch in transcription during stringent response. Our results demonstrate that pRNA synthesis depends on a similar set of contacts between RNAP and 6S RNA as in the case of promoter-dependent transcription initiation and reveal that both processes can be regulated by universal transcription factors acting on RNAP.

Single-molecule tracking reveals the functional allocation, in vivo interactions, and spatial organization of universal transcription factor NusG

During transcription elongation, NusG aids RNA polymerase by inhibiting pausing, promoting anti-termination on rRNA operons, coupling transcription with translation on mRNA genes, and facilitating Rho-dependent termination. Despite extensive work, the invivo functional allocation and spatial distribution of NusG remain unknown. Using single-molecule tracking and super-resolution imaging in live E.coli cells, we found NusG predominantly in a chromosome-associated population (binding to RNA polymerase in elongation complexes) and a slowly diffusing population complexed with the 30S ribosomal subunit; the latter provides a "30S-guided" path for NusG into transcription elongation. Only ∼10% of NusG is fast diffusing, with its mobility suggesting non-specific interactions with DNA for >50% of the time. Antibiotic treatments and deletion mutants revealed that chromosome-associated NusG participates mainly in rrn anti-termination within phase-separated transcriptional condensates and in transcription-translation coupling. This study illuminates the multiple roles of NusG and offers a guide on dissecting multi-functional machines via invivo imaging.

Effect of electrical stimulation of the thigh muscles on the level of interleukin-6 in traumatic injuries of the anterior cruciate ligament of the knee joint

Traumatic damage to the anterior cruciate ligament leads to impaired support and mechanical instability of the limb. One of the frequent complications after injury is arthrogenic muscle inhibition due to inhibition of the quadriceps muscle and the development of functional contracture. On the contrary, one of the indicators of high muscle activity is a sufficient level in the blood of functional muscle proteins – myokines, in particular interleukin-6, which are expressed and released by muscle fibers. The aim of the study was to study the level of interleukin-6 in men with damage to the anterior cruciate ligament in the dynamics of electromyostimulation of the quadriceps femoris. The study involved 23 men, mean age 34.8±2.2 years, with traumatic injury of the anterior cruciate ligament, who, 10 days before surgery, underwent electromyostimulation of the quadriceps femoris using the INTELECT® Advanced device (Chattanooga (DJO), USA). The control group consisted of 12 healthy men, mean age 32.2±2.4 years. The level of IL-6 was determined in the blood serum before electromyostimulation, and in dynamics using a kit for enzyme immunoassay (Vector-Best, Novosibirsk). The obtained data were processed using the Statistica licensed software package v. 10.0. The basal level of IL-6 in the main group was 1.28 (0.87-1.72) pg/mL, which is significantly lower than in healthy individuals 5.2 (3.8-6.1) pg/mL and is due to a low level of physical activity due to functional contracture of the quadriceps muscle. In the dynamics of electromyostimulation on the 5th day, the level of IL-6 significantly increased by 3.2 times from the basal level, on the 10th day by 4.6 times, while not exceeding that of the group of healthy individuals. With the reduction of myocytes, the concentration of myokine interleukin-6 increased in the cytoplasm of cells, which contributes to the accumulation of macroergs in the muscle cell, due to myokine-dependent activation of glycogenolysis. The reparative and anti-inflammatory properties of IL-6 are realized in stimulated striated muscles by the classical signaling mechanism that can block the activation of the universal intracellular transcription factor NF-κB in relation to the production of pro-inflammatory cytokines. Thus, electromyostimulation before the start of surgical treatment leads to an increase in the concentration of myokine IL-6 in the blood, which contributes to an increase in the anti-inflammatory and reparative potential of damaged tissues.

Structural and functional basis of the universal transcription factor NusG pro-pausing activity in Mycobacterium tuberculosis

Transcriptional pauses mediate regulation of RNA biogenesis. DNA-encoded pause signals trigger pausing by stabilizing RNA polymerase (RNAP) swiveling and inhibiting DNA translocation. The N-terminal domain (NGN) of the only universal transcription factor, NusG/Spt5, modulates pausing through contacts to RNAP and DNA. Pro-pausing NusGs enhance pauses, whereas anti-pausing NusGs suppress pauses. Little is known about pausing and NusG in the human pathogen Mycobacterium tuberculosis (Mtb). We report that MtbNusG is pro-pausing. MtbNusG captures paused, swiveled RNAP by contacts to the RNAP protrusion and nontemplate-DNA wedged between the NGN and RNAP gate loop. In contrast, anti-pausing Escherichia coli (Eco) NGN contacts the MtbRNAP gate loop, inhibiting swiveling and pausing. Using CRISPR-mediated genetics, we show that pro-pausing NGN is required for mycobacterial fitness. Our results define an essential function of mycobacterial NusG and the structural basis of pro- versus anti-pausing NusG activity, with broad implications for the function of all NusG orthologs.

Genome-wide identification of KNOX transcription factors in cotton and the role of GhKNOX4-A and GhKNOX22-D in response to salt and drought stress

Cotton is one of the most important economic and fiber crops in the world. KNOX is one class of universal transcription factors, which plays important roles in plant growth and development as well as response to different stresses. Although there are many researches on KNOXs in other plant species, there are few reports on cotton. In this study, we systematically and comprehensively identified all KNOX genes in upland cotton and its two ancestral species; we also studied their functions by employing RNA-seq analysis and virus-induced gene silence (VIGS). A total of 89 KNOX genes were identified from three cotton species. Among them, 44 were from upland cotton, 22 and 23 were found in its ancestral species G. raimondii and G. arboreum, respectively. Plant polyploidization and domestication play a selective force driving KNOX gene evolution. Phylogenetic analysis displayed that KNOX genes were evolved into three Classes. The intron length and exon number differed in each Class. Transcriptome data showed that KNOX genes of Class II were widely expressed in multiple tissues, including fiber. The majority of KNOX genes were induced by different abiotic stresses. Additionally, we found multiple cis-elements related to stress in the promoter region of KNOX genes. VIGS silence of GhKNOX4-A and GhKNOX22-D genes showed significant growth and development effect in cotton seedlings under salt and drought treatments. Both GhKNOX4-A and GhKNOX22-D regulated plant tolerance; silencing both genes induced oxidative stresses, evidenced by reduced SOD activity and induced leave cell death, and also enhanced stomatal open and water loss. Thus, GhKNOX4-A and GhKNOX22-D may contribute to drought response by regulating stomata opening and oxidative stresses.

Natural Phaeosphaeride A Derivatives Overcome Drug Resistance of Tumor Cells and Modulate Signaling Pathways.

In the present study, natural phaeosphaeride A (PPA) derivatives are synthesized. Anti-tumor studies are carried out on the PC3, K562, HCT-116, THP-1, MCF-7, A549, NCI-H929, Jurkat, and RPMI8226 tumor cell lines, and on the human embryonic kidney (HEK293) cell line. All the compounds synthesized turned out to have better efficacy than PPA towards the tumor cell lines listed. Among them, three compounds exhibited an ability to overcome the drug resistance of tumor cells associated with the overexpression of the P-glycoprotein by modulating the work of this transporter. Luminex xMAP technology was used to assess the effect of five synthesized compounds on the activation of intracellular kinase cascades in A431 cells. MILLIPLEX MAP Multi-Pathway Magnetic Bead 9-Plex was used, which allowed for the simultaneous detection of the following nine phosphorylated protein markers of the main intracellular signaling pathways: a universal transcription factor that controls the expression of immune-response genes, apoptosis and cell cycle NFκB (pS536); cAMP-dependent transcription factor (CREB (pS133); mitogen-activated kinase p38 (pT180/pY182); stress-activated protein kinase JNK (pT183/pY185); ribosomal SK; transcription factors STAT3 (pS727) and STAT5A/B (pY694/699); protein kinase B (Akt) (pS473); and kinase regulated by extracellular signals ERK1/2 (pT185/pY187). The effect of various concentrations of PPA derivatives on the cell culture was studied using xCelligence RTCA equipment. The compounds were found to modulate JNK, ERK1/2, and p38 signaling pathways. The set of activated kinase cascades suggests that oxidative stress is the main probable mechanism of the toxic action of PPA derivatives.

Locating TATA Binding Protein in the RNA Polymerase I Pre‐Initiation Complex

Transcription of eukaryotic DNA into RNA is carried by three main RNA polymerases (Pols I–III). Pol I synthesizes ribosomal DNA (rDNA) into ribosomal RNA (rRNA), which has been directly linked to the rate of protein synthesis, cell growth and proliferation. The efficiency of Pols’ function is controlled by general transcription factors, which enable the enzyme to interact with promoter DNA at the initiation stage. In Saccharomyces cerevisiae, Pol I transcription initiation relies on four main factors, one of which is TATA Binding Protein (TBP). TBP is an essential universal transcription factor used by all three eukaryotic Pols. As its name eludes, TBP typically binds to TATA motifs found in promoter DNA. Interestingly, unlike Pol II and III, Pol I promoters are TATA‐less. Thus, unlike the location of TBPs in other PICs, the location and function of TBP within the Pol I PIC remains unclear.Current Cryo‐EM structures of CF‐DNA‐Pol I initiation complex leaves little room for TBP to bind to its “typical” Pols II/III position. Therefore, we hypothesize that TBP must occupy a unique location, putatively more upstream, within the Pol I PIC. Combining available structural data with previous crosslinking data of CF and TBP, we modeled the interaction between the two proteins with varying distance constraints. In addition, we analyzed TBPs location on the rDNA promoter by site‐directed hydroxyl radical cleavage experiment, known as FeBABE, where DNA phosphothioate modification probes were constructed based on our predicted models. Our results from these combinational methods elucidated that TBP locates more upstream within Pol I PIC.Support or Funding InformationThis work was a part of SUNY Upstate Medical School’s Summer Undergraduate Research Fellowship 2019 and was supported by National Cancer Institute (NCI), National Institute for Dental and Craniofacial Research (NIDCR), and Carol Baldwin Research Foundation.FeBABE site‐directed hydroxyl radical cleavage.A and B. Sites of FeBABE incorporation into rDNA promoter in clusters of 5 include the “typical” location of TBP (1), upstream of the CE (2), 5′ of CE (3), and within the CE (4). C. Western blot showed FeBABE specific cleavage products. Cleavages were observed when FeBABE was incorporated at all four positions. Most intense cleavages were observed when FeBABE is incorporated upstream of the CE. D. Quantitation of TBP cleavages.Figure 1

Regionally Distinct Astrocytes Display Unique Transcription Factor Profiles in the Adult Brain.

Astrocytes are the most abundant type of glial cell in the central nervous system and perform a myriad of vital functions, however, the nature of their diversity remains a longstanding question in neuroscience. Using transcription factor motif discovery analysis on region-specific gene signatures from astrocytes we uncovered universal and region-specific transcription factor expression profiles. This analysis revealed that motifs for Nuclear Factor-I (NFI) are present in genes enriched in astrocytes from all regions, with NFIB and NFIX exhibiting pan-astrocyte expression in the olfactory bulb, hippocampus, cortex, and brainstem. Further analysis into region-specific motif patterns, identified Nkx3-1, Stat4, Pgr, and Nkx6-1 as prospective region-specific transcription factors. Validation studies revealed that Nkx6-1 is exclusively expressed in astrocytes in the brainstem and associates with the promoters of several brainstem specific target genes. These studies illustrate the presence of multiple transcriptional layers in astrocytes across diverse brain regions and provide a new entry point for examining how astrocyte diversity is specified and maintained.

Gre-family factors modulate DNA damage sensing by Deinococcus radiodurans RNA polymerase

ABSTRACTDeinococcus radiodurans is a highly stress resistant bacterium that encodes universal as well as lineage-specific factors involved in DNA transcription and repair. However, the effects of DNA lesions on RNA synthesis by D. radiodurans RNA polymerase (RNAP) have never been studied. We investigated the ability of this RNAP to transcribe damaged DNA templates and demonstrated that various lesions significantly affect the efficiency and fidelity of RNA synthesis. DNA modifications that disrupt correct base-pairing can strongly inhibit transcription and increase nucleotide misincorporation by D. radiodurans RNAP. The universal transcription factor GreA and Deinococcus-specific factor Gfh1 stimulate RNAP stalling at various DNA lesions, depending on the type of the lesion and the presence of Mn2+ ions, abundant divalent cations in D. radiodurans. Furthermore, Gfh1 stimulates the action of the Mfd translocase, which removes transcription elongation complexes paused at the sites of DNA lesions. Thus, Gre-family factors in D. radiodurans might have evolved to increase the efficiency of DNA damage recognition by the transcription and repair machineries in this bacterium.

Inhibition of Nuclear Factor‐KappaB Improves Nitric Oxide‐Dependent Dilation in the Cutaneous Microvasculature of Psoriatic Adults

Psoriasis is a chronic autoimmune disease and is associated with an increased risk of cardiovascular mortality. Systemic inflammation characteristic of psoriasis contributes to the development of cardiovascular disease (CVD) by inducing peripheral vascular dysfunction. Inflammatory signals involved in the pathogenesis of psoriasis activate the universal transcription factor, nuclear factor κB (NFκB). NFκB activation has been strongly linked to vascular dysfunction through multiple mechanisms that reduce nitric oxide (NO) bioavailability. However, the role of NFκB activation in contributing to microvascular endothelial dysfunction has not been examined in psoriatic adults. We tested the hypothesis that systemic inhibition of NFκB (high‐dose oral salsalate) would improve NO‐mediated endothelium‐dependent vasodilation in psoriatic adults. Eight adults (3M, 5F; 35 ± 6 yr) with moderate plaque psoriasis (11% lesional body surface area) and eight healthy age‐ and sex‐matched non‐psoriatic adults (3M, 5F; 37 ± 6 yr) ingested salsalate (3000 mg/d) or placebo for 4 days in a randomized, cross‐over design. On the fourth day of the intervention, microvascular endothelial function was assessed utilizing a physiological eNOS‐dependent stimulus combined with intradermal microdialysis in a non‐lesional skin site on the forearm. Red cell flux (laser Doppler flowmetry) was measured during local skin heating (42°C), until an established plateau had been reached. Then NO‐dependent vasodilation was directly quantified through perfusion of the nonspecific NO synthase inhibitor NG‐nitro‐l‐arginine methyl ester (15 mM). Cutaneous vascular conductance (CVC = red cell flux/mean arterial pressure) was calculated and normalized to a percentage of maximum (28 mM sodium nitroprusside, 43°C). Plasma salicylate concentrations were similarly elevated following salsalate treatment in psoriatic and healthy adults (psoriasis: 24.0 ± 8.5 vs healthy: 22.2 ± 7.9 mg/dL; p=0.51). In psoriatic adults, C‐reactive protein (CRP) concentrations were clinically elevated during placebo (3.4 ± 1.2 mg/L) but not during salsalate treatment (1.5 ± 0.5 mg/L). NO‐dependent vasodilation was reduced in psoriatic adults compared to healthy adults during placebo (psoriasis: 20.9 ± 5.1 vs healthy: 40.1 ± 7.3 %CVCmax; p = 0.051) but not during salsalate treatment (psoriasis: 32.2 ± 3.7 vs healthy: 31.4 ± 6.2 %CVCmax; p = 0.86). These preliminary data suggest that inhibition of NFκB improves NO‐mediated endothelium‐dependent vasodilation in psoriatic adults. Treatment strategies for psoriasis that target inflammatory signaling pathways, specifically NFκB, may secondarily improve vascular function and reduce psoriasis‐associated CVD risk.Support or Funding InformationSupported by AHA 16PRE31060000 and NIH R01HL093238; author views not official US Army or DOD policyThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

BASIC PENTACYSTEINE Proteins Repress ABSCISIC ACID INSENSITIVE4 Expression via Direct Recruitment of the Polycomb-Repressive Complex 2 in Arabidopsis Root Development.

Plant transcription factors generally act in complex regulatory networks that function at multiple levels to govern plant developmental programs. Dissection of the interconnections among different classes of transcription factors can elucidate these regulatory networks and thus improve our understanding of plant development. Here, we investigated the molecular and functional relationships of the transcription factors ABSCISIC ACID INSENSITIVE 4 (ABI4) and members of the BASIC PENTACYSTEINE (BPC) family in lateral root (LR) development of Arabidopsis thaliana. Genetic analysis showed that BPCs promote LR development by repressing ABI4 expression. Molecular analysis showed that BPCs bind to the ABI4 promoter and repress ABI4 transcription in roots. BPCs directly recruit the Polycomb Repressive Complex 2 (PRC2) to the ABI4 locus and epigenetically repress ABI4 expression by catalyzing the trimethylation of histone H3 at Lys27. In addition, BPCs and ABI4 co-ordinate their activities to fine-tune the levels of PIN-FORMED1, a component of the auxin signaling pathway, and thus modulate LR formation. These results establish a functional relationship between two universal and multiple-role transcription factors, and provide insight into the mechanisms of the transcriptional regulatory networks that affect Arabidopsis organogenesis.

Arachidonic Acid Cascade Driven Neurotoxicity in Hypobaric Hypoxia: An invivo Study

BackgroundA continuous supply of oxygen to cerebral tissue is required for maintaining its homeostasis. Any interruption in delivery of oxygen leads to cerebral hypoxia related neuronal damage. . The growing bodies of evidences reveal that cerebral hypoxia induced at high altitude promotes the production of excessive ROS resulting in oxidative stress. Cerebral tissue is prone to oxidative stress damage because of high content of PUFA in their cell membrane and weak antioxidant defence system. Arachidonic acid(C20) is the most abundant form of PUFA which is present in brain. Under stress conditions arachidonic acid is metabolized by cyclooxygenase(COX‐2) and 12/15 Lipoxygenase in cerebral tissue which leads to the production of several prooxidant and anti‐inflammatory molecules. Experimental studies suggest that hypoxia induce oxidative burden which initiate the upregulation of arachodonic acid cascade enzyme 12/15LOX and COX‐2.MethodIn present study we aimed to investigate the modulatory role of 12/15 LOX and COX‐2 by using specific inhibitor of 12/15 LOX (baicalein) and COX‐2 (NS398) on neuronal damage induced by hypobaric hypoxia.ResultsAnimals subjected to hypobaric hypoxia in a specially designed decompression chamber experience cerebral hypoxia as confirmed by the elevated expression of HIF‐1a protein which is universal transcription factor that senses oxygen balance in cellular milieu. Further COX‐2 and 12/15 lipoxygenase gene and protein expression were significantly upregulated in hypoxia condition. Moreover histopathological study showed marked increase in death of neurons in hypoxia condition and inhibitor of 12/15 LOX and COX‐2 attenuated the neurotoxicity during cerebral hypoxia suggesting the contribution of arachidonic acid cascade in hypoxia condition. In addition to above biochemical studies like LDH assay, MDA assay for lipid peroxidation and nitric oxide levels revealed that oxidative stress mediated neuronal damage caused by hypoxia was attenuated significantly by 12/15 LOX and COX‐2 inhibitors confirming involvement of 12/15 LOX and COX‐2. TUNEL analysis confirmed the apoptotic form of cell death in hypoxia as dUTP labeled DNA fragments were significantly increased further 12/15LOX and COX‐2 enzyme inhibitor rescued the neuronal cells from apoptosis.ConclusionThe primary study using pharmacological inhibitors provide the strong evidence towards the contribution of arachidonic acid cascade in pathogenesis of cerebral hypoxia injury .Support or Funding InformationAuthors acknowledge Council for Scientific and Industrial Research (CSIR) India for financial assistance.

The association and prognostic relevance of cancerous inhibitor of protein phosphatase 2A and inflammation in tongue squamous cell carcinoma.

Cancerous inhibitor of protein phosphatase 2A (CIP2A) prevents proteolytic degradation of a universal transcription factor, c-Myc. Strong CIP2A expression associates with poor prognosis in early-stage tongue cancer and in other cancers. The aim of this study was to evaluate CIP2A and mucosal inflammation in tongue hyperplasia, in tongue cancer, and in its metastasis. Retrospective tongue and lymph node specimens (n = 105) were stained immunohistochemically with polyclonal antibody anti-CIP2A. CIP2A staining intensity and inflammation were assessed semi-quantitatively with light microscopy. CIP2A was similarly detected in tongue cancer and tongue hyperplasia, whereas local inflammation was stronger in cancer (p = 0.000). CIP2A expression was increased in metastasized cancer compared to non-metastasized (p = 0.019). Markers for poorer survival were tumor size of ≥20 mm, presence of metastasis and nodal CIP2A (p = 0.031, p = 0.000, p = 0.042). Cancer patients aged ≥60 with increased inflammation predicted poor survival (p = 0.037). CIP2A and inflammation might play a role in progression of tongue cancer.

Expression of zma-miR169 miRNAs and their target ZmNF-YA genes in response to abiotic stress in maize leaves

The miR169 miRNA family is highly conserved in plants. Its members regulate the expression of genes encoding the universal transcription factor subunit NUCLEAR FACTOR-Y subunit A (NF-YA) via transcript cleavage. NF-YA regulates gene expression by binding the CCAAT box sequence in target promoters. The miR169/NF-YA module plays a critical role during plant development and in plant responses to abiotic stress. We characterized the secondary structures of maize pre-miR169 miRNAs and predicted their potential gene targets. Coexpression of zma-miR169 and ZmNF-YA in Nicotiana benthamiana demonstrated that mutations in or deletion of target sites abolished regulation by zma-miR169. Maize seedlings were subjected to short-term (0–48h) and long-term (15days) drought, abscisic acid (ABA), or salt stress. Long-term exposure to PEG (drought stress) or NaCl (salt stress) repressed seedling growth. We investigated the expression patterns of zma-miR169s and their target ZmNF-YA genes in maize leaves and found diverse changes in expression in response to the three stress treatments. The expression of most zma-miR169 genes was downregulated by PEG and upregulated by ABA. In response to salt stress, zma-miR169 genes were upregulated initially and subsequently downregulated. Most ZmNF-YA genes were upregulated during the short term and downregulated by 15days in response to the three stress treatments.

Identification of STAT5A and STAT5B Target Genes in Human T Cells

Signal transducer and activator of transcription (STAT) comprises a family of universal transcription factors that help cells sense and respond to environmental signals. STAT5 refers to two highly related proteins, STAT5A and STAT5B, with critical function: their complete deficiency is lethal in mice; in humans, STAT5B deficiency alone leads to endocrine and immunological problems, while STAT5A deficiency has not been reported. STAT5A and STAT5B show peptide sequence similarities greater than 90%, but subtle structural differences suggest possible non-redundant roles in gene regulation. However, these roles remain unclear in humans. We applied chromatin immunoprecipitation followed by DNA sequencing using human CD4+ T cells to detect candidate genes regulated by STAT5A and/or STAT5B, and quantitative-PCR in STAT5A or STAT5B knock-down (KD) human CD4+ T cells to validate the findings. Our data show STAT5A and STAT5B play redundant roles in cell proliferation and apoptosis via SGK1 interaction. Interestingly, we found a novel, unique role for STAT5A in binding to genes involved in neural development and function (NDRG1, DNAJC6, and SSH2), while STAT5B appears to play a distinct role in T cell development and function via DOCK8, SNX9, FOXP3 and IL2RA binding. Our results also suggest that one or more co-activators for STAT5A and/or STAT5B may play important roles in establishing different binding abilities and gene regulation behaviors. The new identification of these genes regulated by STAT5A and/or STAT5B has major implications for understanding the pathophysiology of cancer progression, neural disorders, and immune abnormalities.

BHLH122 is important for drought and osmotic stress resistance in Arabidopsis and in the repression of ABA catabolism

• Although proteins in the basic helix-loop-helix (bHLH) family are universal transcription factors in eukaryotes, the biological roles of most bHLH family members are not well understood in plants. • The Arabidopsis thaliana bHLH122 transcripts were strongly induced by drought, NaCl and osmotic stresses, but not by ABA treatment. Promoter::GUS analysis showed that bHLH122 was highly expressed in vascular tissues and guard cells. Compared with wild-type (WT) plants, transgenic plants overexpressing bHLH122 displayed greater resistance to drought, NaCl and osmotic stresses. In contrast, the bhlh122 loss-of-function mutant was more sensitive to NaCl and osmotic stresses than were WT plants. • Microarray analysis indicated that bHLH122 was important for the expression of a number of abiotic stress-responsive genes. In electrophoretic mobility shift assay and chromatin immunoprecipitation assays, bHLH122 could bind directly to the G-box/E-box cis-elements in the CYP707A3 promoter, and repress its expression. Further, up-regulation of bHLH122 substantially increased cellular ABA levels. • These results suggest that bHLH122 functions as a positive regulator of drought, NaCl and osmotic signaling.

P53 and Sp1 cooperate to regulate the expression of epstein–barr viral Zta protein

Epstein-Barr virus (EBV) belongs to the gammaherpesvirus family. To produce infectious progeny, EBV reactivates from latency into the lytic cycle by expressing the determinative lytic transactivator, Zta. In the presence of histone deacetylase inhibitor (HDACi), p53 is a prerequisite for the initiation of the EBV lytic cycle by facilitating the expression of Zta. In this study, a serial mutational analysis of Zta promoter (Zp) indicated an important role for the ZID element in responding to HDACi induction and p53 binds to this ZID element together with Sp1, a universal transcription factor. Abolition of the DNA-binding ability of Sp1 reduces the inducibility of ZID by HDACi and also reduces the amount of p53 binding to ZID. Finally, it was shown that EBV in p53-positive-lymphoblastoid cell lines (LCLs) can enter into the lytic cycle spontaneously; however, knockdown of p53 in LCLs leads to retardation of EBV reactivation.

The STAT5b Pathway Defect and Autoimmunity

The signal transducer and activator of transcription (STAT) 5b is a universal transcription factor that plays key biological roles in allergic diseases, immunodeficiencies, autoimmunities, cancers, hematological diseases, growth disorders, and lung diseases. The identification of distinct pathological manifestations of STAT5b deficiency in humans has highlighted the critical role of the STAT5b pathway. Proper gene transcription at IL-2R α, FOXP3, Bcl-2, and growth hormone (GH) associated loci are thought to be associated with normal STAT5b transcriptional activity. These genes are thought to play important roles in allergy/autoimmunity, immunodeficiency, cancer/anemia, and growth, respectively. The STAT5A and STAT5B genes are collocated on 17q11. Although these two monomeric proteins exhibit peptide sequence similarities of >90%, it is known through observations of STAT5b deficient subjects that STAT5a and STAT5b are not fully redundant in humans. Patients with STAT5b deficiency have decreased numbers of regulatory CD4+CD25high T cell (Treg) despite their STAT5a levels being normal. Prior studies on STAT5b deficient subjects have revealed immunological aberrations associated with the following disease phenotype: modest lymphopenia and decreased populations of Treg, γ−δ T cells, and natural killer (NK) cells. Most subjects with STAT5b deficiency show severe eczema, and autoimmune disease (juvenile idiopathic arthritis, autoimmune thyroiditis, idiopathic thrombocytic purpura) which are thought to be associated with Treg dysfunction. We will review the likely pathophysiological mechanisms associated with STAT5b deficiency.

Transcriptional dysregulation of TrkA associates with neurodegeneration in spinocerebellar ataxia type 17

TATA binding protein (TBP), a universal transcription factor, is broadly required by nuclear RNA polymerases for the initiation of transcription. TBP contains a polymorphic polyglutamine tract in its N-terminal region, and expansion of this tract leads to spinocerebellar ataxia type 17 (SCA17), one of nine dominantly inherited neurodegenerative diseases caused by polyglutamine expansion in the affected proteins. The expanded polyglutamine proteins are ubiquitously expressed, but cause selective and characteristic neurodegeneration in distinct brain regions in each disease. Unlike many other polyglutamine proteins, whose functions are not yet fully understood, TBP is a well-characterized transcription factor that is restricted to the nucleus. Thus, investigating how mutant TBP mediates neuropathology should help elucidate the mechanisms by which transcriptional dysregulation contributes to neuronal dysfunction and/or neurodegeneration in polyglutamine diseases. To this end, we characterized cellular and mouse models expressing polyQ-expanded TBP. The cell model exhibits characteristic features of neuronal dysfunction, including decreased cell viability and defective neurite outgrowth. We found that the high-affinity nerve growth factor receptor, TrkA, is down-regulated by mutant TBP in cells. Down-regulation of TrkA also occurs in the cerebellum of SCA17 transgenic mice prior to Purkinje cell degeneration. Mutant TBP binds more Sp1, reduces its occupancy of the TrkA promoter and inhibits the activity of the TrkA promoter. These findings suggest that the transcriptional down-regulation of TrkA by mutant TBP contributes to SCA17 pathogenesis.