Immediate inhibition of spinal secretory phospholipase A2 prevents the pain and elevated spinal neuronal hyperexcitability and neuroimmune regulatory genes that develop with nerve root compression.

Cervical nerve root injury induces a host of inflammatory mediators in the spinal cord that initiate and maintain neuronal hyperexcitability and pain. Secretory phospholipase A2 (sPLA2) is an enzyme that has been implicated as a mediator of pain onset and maintenance in inflammation and neural injury. Although sPLA2 modulates nociception and excitatory neuronal signaling in vitro, its effects on neuronal activity and central sensitization early after painful nerve root injury are unknown. This study investigated whether inhibiting spinal sPLA2 at the time of nerve root compression (NRC) modulates the pain, dorsal horn hyperexcitability, and spinal genes involved in glutamate signaling, nociception, and inflammation that are seen early after injury. Rats underwent a painful C7 NRC injury with immediate intrathecal administration of the sPLA2 inhibitor thioetheramide-phosphorlycholine. Additional groups underwent either injury alone or sham surgery. One day after injury, behavioral sensitivity, spinal neuronal excitability, and spinal cord gene expression for glutamate receptors (mGluR5 and NR1) and transporters (GLT1 and EAAC1), the neuropeptide substance P, and pro-inflammatory cytokines (TNFα, IL1α, and IL1ß) were assessed. Treatment with the sPLA2 inhibitor prevented mechanical allodynia, attenuated neuronal hyperexcitability in the spinal dorsal horn, restored the proportion of spinal neurons classified as wide dynamic range, and reduced genes for mGluR5, substance P, IL1α, and IL1ß to sham levels. These findings indicate spinal regulation of central sensitization after painful neuropathy and suggest that spinal sPLA2 is implicated in those early spinal mechanisms of neuronal excitability, perhaps via glutamate signaling, neurotransmitters, or inflammatory cascades.

Genome-wide transcriptomic analysis of a desert willow, Salix psammophila, reveals the function of hub genes SpMDP1 and SpWRKY33 in drought tolerance.

BACKGROUND: Drought is a major environmental constraint to plant growth, development and productivity. Compared with most willows that are generally susceptible to drought, the desert willow Salix psammophila has extraordinary adaptation to drought stress. However, its molecular basis of drought tolerance is still largely unknown. RESULTS: During polyethylene glycol 6000 (PEG 6000)-simulated drought stress, we found that the osmotic adjustment substances were accumulated and the antioxidant enzyme activities were enhanced in S. psammophila roots. A total of 8172 differentially expressed genes were identified in roots of S. psammophila through RNA-Sequencing. Based on K-means clustering, their expression patterns were classified into nine clusters, which were enriched in several stress-related processes including transcriptional regulation, response to various stresses, cell death, etc. Moreover, 672 transcription factors from 45 gene families were differentially expressed under drought stress. Furthermore, a weighted gene co-expression network was constructed, and eight genes were identified as hub genes. We demonstrated the function of two hub genes, magnesium-dependent phosphatase 1 (SpMDP1) and SpWRKY33, through overexpression in Arabidopsis thaliana. Overexpression of the two hub genes enhanced the drought tolerance in transgenic plants, suggesting that the identification of candidate drought tolerance genes in this study was highly efficient and credible. CONCLUSIONS: Our study analyzed the physiological and molecular responses to drought stress in S. psammophila, and these results contribute to dissect the mechanism of drought tolerance of S. psammophila and facilitate identification of critical genes involved in drought tolerance for willow breeding.

Metabolic dependent and independent pH-drop shuts down VirSR quorum sensing in Clostridium perfringens.

Clostridium perfringens produces various exotoxins and enzymes that cause food poisoning and gas gangrene. The genes involved in virulence are regulated by the agr-like quorum sensing (QS) system, which consists of a QS signal synthesis system and a VirSR two-component regulatory system (VirSR TCS) which is a global regulatory system composed of signal sensor kinase (VirS) and response regulator (VirR). We found that the perfringolysin O gene (pfoA) was transiently expressed during mid-log phase of bacterial growth; its expression was rapidly shut down thereafter, suggesting the existence of a self-quorum quenching (sQQ) system. The sQQ system was induced by the addition of stationary phase culture supernatant (SPCS). Activity of the sQQ system was heat stable, and was present following filtration through the ultrafiltration membrane, suggesting that small molecules acted as sQQ agents. In addition, sQQ was also induced by pure acetic and butyric acids at concentrations equivalent to those in the stationary phase culture, suggesting that organic acids produced by C. perfringens were involved in sQQ. In pH-controlled batch culture, sQQ was greatly diminished; expression level of pfoA extended to late-log growth phase, and was eventually increased by one order of magnitude. Furthermore, hydrochloric acid induced sQQ at the same pH as was used in organic acids. SPCS also suppressed the expression of genes regulated by VirSR TCS. Overall, the expression of virulence factors of C. perfringens was downregulated by the sQQ system, which was mediated by primary acidic metabolites and acidic environments. This suggested the possibility of pH-controlled anti-virulence strategies.

Expression of the small regulatory RNA gene mmgR is regulated negatively by AniA and positively by NtrC in Sinorhizobium meliloti 2011.

In the N2-fixing symbiont of alfalfa root nodules, Sinorhizobium meliloti 2011, the mmgR gene encodes a 77 nt small untranslated RNA (sRNA) that negatively regulates the accumulation of polyhydroxybutyrate (PHB) when the bacterium is grown under conditions of surplus carbon (C) in relation to nitrogen (N). We previously showed that the expression of mmgR is primarily controlled at the transcriptional level and that it depends on the cellular N status, although the regulatory mechanism and the factors involved were unknown. In this study, we provide experimental data supporting that: (a) mmgR is induced upon N limitation with the maximum expression found at the highest tested C/N molar ratio in the growth medium; (b) a conserved heptamer TTGTGCA located between the -35 and -10 mmgR promoter elements is necessary and sufficient for induction by N limitation; (c) induction of mmgR requires the N-status regulator NtrC; (d) under C limitation, mmgR transcription is repressed by AniA, a global regulator of C flow; (e) the mmgR promoter contains a conserved dyadic motif (TGC[N3]GCA) partially overlapping the heptamer TTGTGCA, which was also found in the promoters of the PHB-related genes phaP1, phaP2, phaZ and phaR (aniA) of S. meliloti and other alpha-proteobacteria. Taken together, these results suggest that the mmgR promoter would integrate signals from the metabolism of C and N through - at least - the global regulators NtrC and AniA, to provide an optimal level of the MmgR sRNA to fine-tune gene expression post-transcriptionally according to varying C and N availability.

Transcriptome sequencing identifies potential regulatory genes involved in chicken eggshell brownness.

Brown eggs are popular in many countries, and consumers regard eggshell brownness as an important indicator of egg quality. Brown eggshell color is controlled by polygene. However, the responsible genes and detailed molecular mechanisms regulating eggshell brownness have not been defined. In the present study, we applied the RNA-seq technology to analyze the transcriptome data of the shell gland epithelium of hens and investigated the candidate genes associated with eggshell brownness. The results indicated that 8461 genes were expressed in the shell gland epithelium, of which 34 genes were differentially expressed in hens laying dark vs. light brown eggs. Functional analysis revealed that two genes, ovotransferrin (TF) and heat-shock protein 70 (HSP70), as well as the oxidative phosphorylation pathway were involved in the synthesis and transport of protoporphyrin Ⅸ, which might influence the formation of eggshell brownness and result in different shades of brown.

Whole genome transcriptomics reveals global effects including up-regulation of Francisella pathogenicity island gene expression during active stringent response in the highly virulent Francisella tularensis subsp. tularensis SCHU S4.

During conditions of nutrient limitation bacteria undergo a series of global gene expression changes to survive conditions of amino acid and fatty acid starvation. Rapid reallocation of cellular resources is brought about by gene expression changes coordinated by the signalling nucleotides' guanosine tetraphosphate or pentaphosphate, collectively termed (p)ppGpp and is known as the stringent response. The stringent response has been implicated in bacterial virulence, with elevated (p)ppGpp levels being associated with increased virulence gene expression. This has been observed in the highly pathogenic Francisella tularensis sub spp. tularensis SCHU S4, the causative agent of tularaemia. Here, we aimed to artificially induce the stringent response by culturing F. tularensis in the presence of the amino acid analogue l-serine hydroxamate. Serine hydroxamate competitively inhibits tRNAser aminoacylation, causing an accumulation of uncharged tRNA. The uncharged tRNA enters the A site on the translating bacterial ribosome and causes ribosome stalling, in turn stimulating the production of (p)ppGpp and activation of the stringent response. Using the essential virulence gene iglC, which is encoded on the Francisella pathogenicity island (FPI) as a marker of active stringent response, we optimized the culture conditions required for the investigation of virulence gene expression under conditions of nutrient limitation. We subsequently used whole genome RNA-seq to show how F. tularensis alters gene expression on a global scale during active stringent response. Key findings included up-regulation of genes involved in virulence, stress responses and metabolism, and down-regulation of genes involved in metabolite transport and cell division. F. tularensis is a highly virulent intracellular pathogen capable of causing debilitating or fatal disease at extremely low infectious doses. However, virulence mechanisms are still poorly understood. The stringent response is widely recognized as a diverse and complex bacterial stress response implicated in virulence. This work describes the global gene expression profile of F. tularensis SCHU S4 under active stringent response for the first time. Herein we provide evidence for an association of active stringent response with FPI virulence gene expression. Our results further the understanding of the molecular basis of virulence and regulation thereof in F. tularensis. These results also support research into genes involved in (p)ppGpp production and polyphosphate biosynthesis and their applicability as targets for novel antimicrobials.

Probing the sRNA regulatory landscape of P. aeruginosa: post-transcriptional control of determinants of pathogenicity and antibiotic susceptibility.

During environmental adaptation bacteria use small regulatory RNAs (sRNAs) to repress or activate expression of a large fraction of their proteome. We extended the use of the in vivo RNA proximity ligation method toward probing global sRNA interactions with their targets in Pseudomonas aeruginosa and verified the method with a known regulon controlled by the PrrF1 sRNA. We also identified two sRNAs (Sr0161 and ErsA) that interact with the mRNA encoding the major porin OprD responsible for the uptake of carbapenem antibiotics. These two sRNAs base pair with the 5' UTR of oprD leading to increase in resistance of the bacteria to meropenem. Additional proximity ligation experiments and enrichment for Sr0161 targets identified the mRNA for the regulator of type III secretion system. Interaction between the exsA mRNA and Sr0161 leads to a block in the synthesis of a component of the T3SS apparatus and an effector. Another sRNA, Sr006, positively regulates, without Hfq, the expression of PagL, an enzyme responsible for deacylation of lipid A, reducing its pro-inflammatory property and resulting in polymyxin resistance. Therefore, an analysis of global sRNA-mRNA interactions can lead to discoveries of novel pathways controlling gene expression that are likely integrated into larger regulatory networks.

Stringent Response Regulators Contribute to Recovery from Glucose Phosphate Stress in Escherichia coli.

In enteric bacteria such as Escherichia coli, the transcription factor SgrR and the small RNA SgrS regulate the response to glucose phosphate stress, a metabolic dysfunction that results in growth inhibition and stems from the intracellular accumulation of sugar phosphates. SgrR activates the transcription of sgrS, and SgrS helps to rescue cells from stress in part by inhibiting the uptake of stressor sugar phosphates. While the regulatory targets of this stress response are well described, less is known about how the SgrR-SgrS response itself is regulated. To further characterize the regulation of the glucose phosphate stress response, we screened global regulator gene mutants for growth changes during glucose phosphate stress. We found that deleting dksA, which encodes a regulator of the stringent response to nutrient starvation, decreases growth under glucose phosphate stress conditions. The stringent response alarmone regulator ppGpp (synthesized by RelA and SpoT) also contributes to recovery from glucose phosphate stress: as with dksA, mutating relA and spoT worsens the growth defect of an sgrS mutant during stress, although the sgrS relA spoT mutant defect was only detectable under lower stress levels. In addition, mutating dksA or relA and spoT lowers sgrS expression (as measured with a P sgrS -lacZ fusion), suggesting that the observed growth defects may be due to decreased induction of the glucose phosphate stress response or related targets. This regulatory effect could occur through altered sgrR transcription, as dksA and relA spoT mutants also exhibit decreased expression of a P sgrR -lacZ fusion. Taken together, this work supports a role for stringent response regulators in aiding the recovery from glucose phosphate stress.IMPORTANCE Glucose phosphate stress leads to growth inhibition in bacteria such as Escherichia coli when certain sugar phosphates accumulate in the cell. The transcription factor SgrR and the small RNA SgrS alleviate this stress in part by preventing further sugar phosphate transport. While the regulatory mechanisms of this response have been characterized, the regulation of the SgrR-SgrS response itself is not as well understood. Here, we describe a role for stringent response regulators DksA and ppGpp in the response to glucose phosphate stress. sgrS dksA and sgrS relA spoT mutants exhibit growth defects under glucose phosphate stress conditions. These defects may be due to a decrease in stress response induction, as deleting dksA or relA and spoT also results in decreased expression of sgrS and sgrR This research presents one of the first regulatory effects on the glucose phosphate stress response outside SgrR and SgrS and depicts a novel connection between these two metabolic stress responses.

Genetic and environmental modifiers of Wilson disease.

Wilson disease (WD) is characterized by remarkable variety in its phenotypic presentation. Patients with WD can present with hepatic, neurologic, and psychiatric symptoms combined in different and unpredictable ways. Importantly, no convincing phenotype-genotype correlation has ever been identified, opening the possibility that other genes, aside from ATPase copper-transporting beta (ATP7B), are involved in the pathogenesis of this condition. In addition, modifier genes, or genes that can affect the expression of other genes, may be involved. Clinical and basic science data indicate that environmental and dietary factors can potentially modify gene expression in WD and, consequently, its clinical presentation and course. In particular, previously studied genes include copper metabolism domain-containing 1 (COMMD1), antioxidant 1 copper chaperone (ATOX1), X-linked inhibitor of apoptosis (XIAP), apolipoprotein E (APOE), hemochromatosis (HFE), and 5,10-methylenetetrahydrofolate reductase (MTHFR). Dietary factors include iron and methyl group donors which could affect methionine metabolism and epigenetic mechanisms of gene expression regulation. Most of the work conducted in this field is in its initial stages but it has the potential to change the diagnosis and treatment of WD.

Gene Regulatory Network Inferences Using a Maximum-Relevance and Maximum-Significance Strategy.

Recovering gene regulatory networks from expression data is a challenging problem in systems biology that provides valuable information on the regulatory mechanisms of cells. A number of algorithms based on computational models are currently used to recover network topology. However, most of these algorithms have limitations. For example, many models tend to be complicated because of the "large p, small n" problem. In this paper, we propose a novel regulatory network inference method called the maximum-relevance and maximum-significance network (MRMSn) method, which converts the problem of recovering networks into a problem of how to select the regulator genes for each gene. To solve the latter problem, we present an algorithm that is based on information theory and selects the regulator genes for a specific gene by maximizing the relevance and significance. A first-order incremental search algorithm is used to search for regulator genes. Eventually, a strict constraint is adopted to adjust all of the regulatory relationships according to the obtained regulator genes and thus obtain the complete network structure. We performed our method on five different datasets and compared our method to five state-of-the-art methods for network inference based on information theory. The results confirm the effectiveness of our method.

Dynamic changes in the main regulatory genes of mitochondrial permeability transition pore in Eimeria tenella host cells.

The purpose of the present study was to investigate the dynamic changes in the main regulatory genes of the mitochondrial permeability transition pore in E. tenella host cells. Primary chick embryo cecum epithelial cell culture techniques, spectrophotometer technology, Hoechst-Annexin V-PI apoptosis staining and ELISA were used to detect the apoptosis rate and dynamic changes of Bcl-2, Bcl-xl, Bax, Bak, Bid, Bad, HK-II, and ATP content in E. tenella host cells at 4, 24, 48, 72, 96, and 120 h. The rates of early apoptosis, late apoptosis, and necrosis of group T0 were significantly lower (P < 0.05) or highly significantly lower (P < 0.01) than those of group C at 4 h, but higher (P < 0.05 or P < 0.01) at varying degrees than those of the same group at 24-120 h. Compared to group C, the amount of Bcl-2, ATP, Bax and Bad in group T0 were visibly lower (P < 0.05 or P < 0.01) at 4 h, whereas Bcl-xl/Bax was highly significantly higher (P < 0.01) at 4 h. In addition, group T0 had less ATP at 24-120 h than group C, whereas the amount of Bcl-2, Bcl-xl, Bax, Bak, Bid, Bad and HK-II in group T0 inversely increased in varying degrees at 24-120 h compared with group C. Moreover, Bcl-2/Bax was lower (P < 0.01) at 24, 48, and 96 h, and Bcl-xl/Bax was lower (P < 0.05) at 48 h in group T0 than in group C, respectively. Taken together, these observations indicate that in the early developmental stages of E. tenella, the host-cell apoptosis rate decreased; although the amount of anti- and pro-apoptotic genes in host cells decreased, the ratios of anti-apoptotic to pro-apoptotic bcl-2 gene-family members increased. In the middle and later developmental stages of E. tenella, the host-cell apoptosis rate increased; the amount of anti- and pro-apoptotic genes increased, while the ratios of anti-apoptotic to pro-apoptotic bcl-2 gene-family members decreased. In addition, ATP decreased at all developmental stages of E. tenella.

[Analysis of microRNA regulatory network in cochlear hair cells with oxidative stress injury].

Objective: To analysis the important genes and functions of cochlear hair cells with oxidative stress injury, by the construction of gene regulatory network which based on different miRNA in cochlear hair cells in vitro with oxidative stress injury, and to explore the molecular mechanisms of deafness based on oxidative stress injury. Method: The oxidative stress damage cochlear hair cell model was induced by 200 µmol/L t-BHP exposure in vitro. Small RNA deep sequencing analyzed the difference expression of miRNA and contructed gene regulatory network by 6 most significant difference miRNA. The important interaction genes in regulatory network were screened and important genes function were annotated by GeneCards. Result: There were 24 different miRNAs in cochlear hair cells with oxidative stress injury by sRNA deep sequencing.Six most significant difference miRNA were: mir-1934 (logFC=2.367 947, P=2.35×10-7), mir-411 (logFC=2.093 687, P=3.13×10-6), mir-717 (logFC=1.927 67, P=3.24×10-5), mir-503 (logFC=-2.021 45, P=3.07×10-6), mir-467e (logFC=-1.953 28, P=0.000 137), and mir-699o (logFC=-1.950 06, P=0.000 517). Eleven important genes in miRNA regulatory network were: Akt1, Src, Ctnnb1, Creb1, Ccnd1, Egfr, Gsk3b, Pten, Cdh1, Fras1, and Ccnd2. Their main functions were to regulate hair cells apoptosis and proliferation by different intracellular signaling pathways. Conclusion: There are many signaling pathways (PI3K-AKT/PKB signaling pathway, AKT/PKB signaling pathway, Wnt signaling pathway, ERK signaling pathway, and Ras signaling pathway) involved in the regulation of apoptosis and proliferation in cochlear hair cells with oxidative stress injury and these signaling pathways are linked to each other to form a network. PI3K-AKT/PKB signaling pathway seems to be the most active in cochlear hair cells with oxidative stress injury.

Hobit and Blimp1 instruct a universal transcriptional program of tissue residency in lymphocytes.

Tissue-resident memory T (Trm) cells permanently localize to portals of pathogen entry, where they provide immediate protection against reinfection. To enforce tissue retention, Trm cells up-regulate CD69 and down-regulate molecules associated with tissue egress; however, a Trm-specific transcriptional regulator has not been identified. Here, we show that the transcription factor Hobit is specifically up-regulated in Trm cells and, together with related Blimp1, mediates the development of Trm cells in skin, gut, liver, and kidney in mice. The Hobit-Blimp1 transcriptional module is also required for other populations of tissue-resident lymphocytes, including natural killer T (NKT) cells and liver-resident NK cells, all of which share a common transcriptional program. Our results identify Hobit and Blimp1 as central regulators of this universal program that instructs tissue retention in diverse tissue-resident lymphocyte populations.

Functional Analysis of Novel Candidate Regulators of Insulin Secretion in the MIN6 Mouse Pancreatic ß Cell Line.

Elucidating the regulation of glucose-stimulated insulin secretion (GSIS) in pancreatic ß cells is important for understanding and treating diabetes. The pancreatic ß cell line, MIN6, retains GSIS but gradually loses it in long-term culture. The MIN6 subclone, MIN6c4, exhibits well-regulated GSIS even after prolonged culture. We previously used DNA microarray analysis to compare gene expression in the parental MIN6 cells and MIN6c4 cells and identified several differentially regulated genes that may be involved in maintaining GSIS. Here we investigated the potential roles of six of these genes in GSIS: Tmem59l (Transmembrane protein 59 like), Scgn (Secretagogin), Gucy2c (Guanylate cyclase 2c), Slc29a4 (Solute carrier family 29, member 4), Cdhr1 (Cadherin-related family member 1), and Celsr2 (Cadherin EGF LAG seven-pass G-type receptor 2). These genes were knocked down in MIN6c4 cells using lentivirus vectors expressing gene-specific short hairpin RNAs (shRNAs), and the effects of the knockdown on insulin expression and secretion were analyzed. Suppression of Tmem59l, Scgn, and Gucy2c expression resulted in significantly decreased glucose- and/or KCl-stimulated insulin secretion from MIN6c4 cells, while the suppression of Slc29a4 expression resulted in increased insulin secretion. Tmem59l overexpression rescued the phenotype of the Tmem59l knockdown MIN6c4 cells, and immunostaining analysis indicated that the TMEM59L protein colocalized with insulin and GM130, a Golgi complex marker, in MIN6 cells. Collectively, our findings suggested that the proteins encoded by Tmem59l, Scgn, Gucy2c, and Slc29a4 play important roles in regulating GSIS. Detailed studies of these proteins and their functions are expected to provide new insights into the molecular mechanisms involved in insulin secretion.

Involvement of the TetR-Type Regulator PaaR in the Regulation of Pristinamycin I Biosynthesis through an Effect on Precursor Supply in Streptomyces pristinaespiralis.

UNLABELLED: Pristinamycin I (PI), produced by Streptomyces pristinaespiralis, is a streptogramin type B antibiotic, which contains two proteinogenic and five aproteinogenic amino acid precursors. PI is coproduced with pristinamycin II (PII), a member of streptogramin type A antibiotics. The PI biosynthetic gene cluster has been cloned and characterized. However, thus far little is understood about the regulation of PI biosynthesis. In this study, a TetR family regulator (encoded by SSDG_03033) was identified as playing a positive role in PI biosynthesis. Its homologue, PaaR, from Corynebacterium glutamicum serves as a transcriptional repressor of the paa genes involved in phenylacetic acid (PAA) catabolism. Herein, we also designated the identified regulator as PaaR. Deletion of paaR led to an approximately 70% decrease in PI production but had little effect on PII biosynthesis. Identical to the function of its homologue from C. glutamicum, PaaR is also involved in the suppression of paa expression. Given that phenylacetyl coenzyme A (PA-CoA) is the common intermediate of the PAA catabolic pathway and the biosynthetic pathway of L-phenylglycine (L-Phg), the last amino acid precursor for PI biosynthesis, we proposed that derepression of the transcription of paa genes in a ΔpaaR mutant possibly diverts more PA-CoA to the PAA catabolic pathway, thereby with less PA-CoA metabolic flux toward L-Phg formation, thus resulting in lower PI titers. This hypothesis was verified by the observations that PI production of a ΔpaaR mutant was restored by L-Phg supplementation as well as by deletion of the paaABCDE operon in the ΔpaaR mutant. Altogether, this study provides new insights into the regulation of PI biosynthesis by S. pristinaespiralis. IMPORTANCE: A better understanding of the regulation mechanisms for antibiotic biosynthesis will provide valuable clues for Streptomyces strain improvement. Herein, a TetR family regulator PaaR, which serves as the repressor of the transcription of paa genes involved in phenylacetic acid (PAA) catabolism, was identified as playing a positive role in the regulation of pristinamycin I (PI) by affecting the supply of one of seven amino acid precursors, L-phenylglycine, in Streptomyces pristinaespiralis. To our knowledge, this is the first report describing the interplay between PAA catabolism and antibiotic biosynthesis in Streptomyces strains. Considering that the PAA catabolic pathway and its regulation by PaaR are widespread in antibiotic-producing actinomycetes, it could be suggested that PaaR-dependent regulation of antibiotic biosynthesis might commonly exist.

Altered expression of hypoxia-inducible factor-1α (HIF-1α) and its regulatory genes in gastric cancer tissues.

Tissue hypoxia induces reprogramming of cell metabolism and may result in normal cell transformation and cancer progression. Hypoxia-inducible factor 1-alpha (HIF-1α), the key transcription factor, plays an important role in gastric cancer development and progression. This study aimed to investigate the underlying regulatory signaling pathway in gastric cancer using gastric cancer tissue specimens. The integration of gene expression profile and transcriptional regulatory element database (TRED) was pursued to identify HIF-1α ↔ NFκB1 → BRCA1 → STAT3 ← STAT1 gene pathways and their regulated genes. The data showed that there were 82 differentially expressed genes that could be regulated by these five transcription factors in gastric cancer tissues and these genes formed 95 regulation modes, among which seven genes (MMP1, TIMP1, TLR2, FCGR3A, IRF1, FAS, and TFF3) were hub molecules that are regulated at least by two of these five transcription factors simultaneously and were associated with hypoxia, inflammation, and immune disorder. Real-Time PCR and western blot showed increasing of HIF-1α in mRNA and protein levels as well as TIMP1, TFF3 in mRNA levels in gastric cancer tissues. The data are the first study to demonstrate HIF-1α-regulated transcription factors and their corresponding network genes in gastric cancer. Further study with a larger sample size and more functional experiments is needed to confirm these data and then translate into clinical biomarker discovery and treatment strategy for gastric cancer.

Arabidopsis JAGGED links floral organ patterning to tissue growth by repressing Kip-related cell cycle inhibitors.

Plant morphogenesis requires coordinated cytoplasmic growth, oriented cell wall extension, and cell cycle progression, but it is debated which of these processes are primary drivers for tissue growth and directly targeted by developmental genes. Here, we used ChIP high-throughput sequencing combined with transcriptome analysis to identify global target genes of the Arabidopsis transcription factor JAGGED (JAG), which promotes growth of the distal region of floral organs. Consistent with the roles of JAG during organ initiation and subsequent distal organ growth, we found that JAG directly repressed genes involved in meristem development, such as CLAVATA1 and HANABA TARANU, and genes involved in the development of the basal region of shoot organs, such as BLADE ON PETIOLE 2 and the GROWTH REGULATORY FACTOR pathway. At the same time, JAG regulated genes involved in tissue polarity, cell wall modification, and cell cycle progression. In particular, JAG directly repressed KIP RELATED PROTEIN 4 (KRP4) and KRP2, which control the transition to the DNA synthesis phase (S-phase) of the cell cycle. The krp2 and krp4 mutations suppressed jag defects in organ growth and in the morphology of petal epidermal cells, showing that the interaction between JAG and KRP genes is functionally relevant. Our work reveals that JAG is a direct mediator between genetic pathways involved in organ patterning and cellular functions required for tissue growth, and it shows that a regulatory gene shapes plant organs by releasing a constraint on S-phase entry.

[Overexpression of LaeA enhances mevastatin production and reduces sporulation of Penicillium citrinum].

OBJECTIVE: To study the regulation of laeA overexpression on mevastatin production and sporulation in Penicillium citrinum. METHODS: We cloned the laeA gene from Penicillium citrinum and constructed the vector pGiHTGi-laeA. The plasmid pGiHTGi-laeA was transformed in Penicillium citrinum by agrobacterium tumefaciens-mediated transformation. Positive transformants were detected by cloning the hygromycin gene. The mevastatin production of the wild type and OE:: laeA was compared by HPLC. The conidia number was counted by blood counting chamber. The biosynthetic gene cluster expression quantity of mevastatin in the wild type and OE: :laeA were analyzed by qRT-PCR. RESULTS: We constructed the plasmid pGiHTGi-laeA, and screened the positive transformants that overexpress the laeA in Penicillium citrinum. With the overexpression of laeA, the mevastatin production was increased from (0.69 ± 0.12) mg/g to (4.02 ± 0.50) mg/g dry cell weight. Compared to the wild type strain, the laeA expression quantity in the OE :: laeA strain increased 29%, and the mlcB expression increased 72%, the mlcR expression increased 153%. Moreover, the overexpression of laeA would decrease the conidia number. CONCLUSION: Overexpression of LaeA enhances mevastatin production and reduces sporulation of Penicillium citrinum, with increases expression of pathway-regulator mlcR, and biosynthetic gene MlcR. These results could guide global regulatory mechanism of mevastatin biosynthesis and the exploitation of high-production strain.

An SREBP-responsive microRNA operon contributes to a regulatory loop for intracellular lipid homeostasis.

Sterol regulatory element-binding proteins (SREBPs) have evolved as a focal point for linking lipid synthesis with other pathways that regulate cell growth and survival. Here, we have uncovered a polycistrionic microRNA (miRNA) locus that is activated directly by SREBP-2. Two of the encoded miRNAs, miR-182 and miR-96, negatively regulate the expression of Fbxw7 and Insig-2, respectively, and both are known to negatively affect nuclear SREBP accumulation. Direct manipulation of this miRNA pathway alters nuclear SREBP levels and endogenous lipid synthesis. Thus, we have uncovered a mechanism for the regulation of intracellular lipid metabolism mediated by the concerted action of a pair of miRNAs that are expressed from the same SREBP-2-regulated miRNA locus, and each targets a different protein of the multistep pathway that regulates SREBP function. These studies reveal an miRNA "operon" analogous to the classic model for genetic control in bacterial regulatory systems.

Transcriptional control of lipid metabolism by the MarR-like regulator FamR and the global regulator GlxR in the lipophilic axilla isolate Corynebacterium jeikeium K411.

Corynebacterial fatty acid metabolism has been associated with human body odour, and is therefore discussed as a potential target for the development of new deodorant additives. For this reason, the transcription levels of fad genes associated with lipid metabolism in the axilla isolate Corynebacterium jeikeium were analysed during growth on different lipid sources. The transcription of several fad genes was induced two- to ninefold in the presence of Tween 60, including the acyl-CoA dehydrogenase gene fadE6. DNA affinity chromatography identified the MarR-like protein FamR as candidate regulator of fadE6. DNA band shift assays and in vivo reporter gene fusions confirmed the direct interaction of FamR with the mapped fadE6 promoter region. Moreover, DNA affinity chromatography and DNA band shift assays detected the binding of GlxR to the promoter regions of fadE6 and famR, revealing a hierarchical control of fadE6 transcription by a feed-forward loop. Binding of GlxR and FamR to additional fad gene regions was demonstrated in vitro by DNA band shift assays, resulting in the co-regulation of fadA, fadD, fadE and fadH genes. These results shed first light on the hierarchical transcriptional control of lipid metabolism in C. jeikeium, a pathway associated with the development of human axillary odour.