http://www.biochemj.org Biochemical Journal RSS feed -- BJ Gene Immediate Publications 0264-6021 1470-8728 Biochemical Journal http://www.biochemj.org/images/BJ_Name.gif http://www.biochemj.org http://www.biochemj.org/bj/imps/refer.htm?MSID=BJ20111925 Mycoplasma mobile (MmLeuRS). The substitute of CP1 in MmLeuRS is a nonapeptide (MmLinker). We show here that the MmLinker, which is critical for aminoacylation activity of MmLeuRS, could confer remarkable tRNA charging activity to the inactive CP1-deleted LeuRS from Escherichia coli (EcLeuRS) and Aquifex aeolicus (AaLeuRS). Furthermore, CP1 from EcLeuRS could functionally compensate the MmLinker and endow MmLeuRS with post-transfer editing capability. These investigations provide a mechanistic framework for the modular construction of aaRSs and their coordination to achieve catalytic efficiency and fidelity. These results also show that the pre-transfer editing function of LeuRS originates from its conserved synthetic domain, and shed light on future mechanism study.]]> M Tan, W Yan, R Liu, M Wang, X Chen, X Zhou, E Wang 2012-02-01T11:52:02Z doi:10.1042/BJ20111925 Portland Press Limited 2012-02-01 BJ Gene http://www.biochemj.org/bj/imps/refer.htm?MSID=BJ20111584 M Kang, S Choi, S Jeong, S Lee, T Kwak, H Kim, O Jung, M Lee, Y Ko, J Ryu, Y Choi, D Jeong, H Lee, S Ye, S Kim, J Lee 2012-01-31T14:13:54Z doi:10.1042/BJ20111584 Portland Press Limited 2012-01-31 BJ Signal http://www.biochemj.org/bj/imps/refer.htm?MSID=BJ20111645 H Li, J Liu 2012-01-31T12:11:41Z doi:10.1042/BJ20111645 Portland Press Limited 2012-01-31 BJ Gene http://www.biochemj.org/bj/imps/refer.htm?MSID=BJ20111052 2 plays an important role in the modulation of the immune response and the inflammatory process. In this study, we describe a PGE₂ positive feedback for Cyclooxygenase (COX) -2 and microsomal PGE Synthase (mPGES) -1 expression in the macrophage cell line RAW 264.7. Our results show that PGE₂ induces COX-2 and mPGES-1 expression, an effect mimicked by dibutyryl-cAMP (dbcAMP) or Forskolin. Furthermore, cAMP signaling pathway cooperates with LPS in the induction of COX-2 and mPGES-1 transcriptional activation. Analysis of the involvement of EP receptors showed that incubation with EP2 agonists up-regulated both COX-2 and mPGES-1 mRNA levels. Moreover, EP2 receptor over expression enhanced the transcriptional activation of COX-2 and mPGES-1 promoters, being this induction abolished by the PKA inhibitor, H89. Activation of PGE₂/EP2/PKA signaling pathway induced the phosphorylation of the cAMP response element-binding protein (CREB) in macrophages and stimulated the specific binding of this transcription factor to COX-2 and mPGES-1 promoters. Deletion or mutation of potential CRE sites in both promoters diminished their transcriptional activity. In summary, our data demonstrate that activation of PKA/CREB signaling through the EP2 receptor by PGE₂ plays a key role in the expression of COX-2 and mPGES-1 in activated macrophages.]]> M D. Díaz-Muñoz, I C. Osma-García, M Fresno, M A. Iñiguez 2012-01-23T14:40:59Z doi:10.1042/BJ20111052 Portland Press Limited 2012-01-23 BJ Gene http://www.biochemj.org/bj/imps/refer.htm?MSID=BJ20111801 2) biosynthesis have primarily focused on the role of cyclooxygenases. Efforts have shifted towards the specific PGE₂ terminal synthases, particularly microsomal PGE synthase (mPGES-1), which has emerged as the crucial inducible synthase with roles in pain, cancer and inflammation. mPGES-1 is induced by proinflammatory cytokines with studies focusing on the proximal promoter, mediated specifically through Egr-1. Numerous studies demonstrate that the mPGES-1 promoter alone cannot account for the level of IL-1β induction. We identified two DNase I hypersensitive sites within the proximal promoter near the Egr-1 element and a novel distal site near -8.6kb. Functional analysis of the distal site revealed two elements that cooperate with basal promoter expression and a stimulus-dependent enhancer. A specific binding site for CCAAT/enhancer binding protein beta (C/EBPβ) in the enhancer was directly responsible for inducible enhancer activity. ChIP analysis demonstrated constitutive Egr-1 binding to the promoter and induced RNA polymerase II and C/EBPβ binding to the promoter and enhancer, respectively. Knockout/knockdown studies established a functional role for C/EBPβ in mPGES-1 gene regulation and documented interaction between Egr-1 and C/EBPβ highlights the proximal promoter cooperation with a novel distal enhancer element in regulating inducible mPGES-1 expression.]]> J N Walters, J S Bickford, K J Newsom, D E Beachy, S J Barilovits, J Herlihy, H S Nick 2012-01-20T12:25:53Z doi:10.1042/BJ20111801 Portland Press Limited 2012-01-20 BJ Gene http://www.biochemj.org/bj/imps/refer.htm?MSID=BJ20111856 in vitro and in vivo to the proximal promoter region of Ngb gene. Moreover, a κB3 site was found as a pivotal cis-element responsible for hypoxia-induced Ngb promoter activity. NFκB (p65) and Sp1 were also responsible for hypoxia-induced upregulation of Ngb expression. Although there are no conserved HREs (hypoxia-response elements) in the promoter of mouse Ngb gene, our results suggested that HIF1α is also involved in hypoxia-induced Ngb upregulation. In conclusion, we identified that NFκB, Egr1, and Sp1 played important roles in regulation of basal Ngb expression via specific interactions with the mouse Ngb promoter. NFκB, Sp1 and HIF1α contributed to the upregulation of mouse Ngb gene expression under hypoxic conditions.]]> N liu, Z Yu, S Xiang, S Zhao, A Tjärnlund Wolf, C Xing, J Zhang, X Wang 2012-01-13T11:45:00Z doi:10.1042/BJ20111856 Portland Press Limited 2012-01-13 BJ Gene http://www.biochemj.org/bj/imps/refer.htm?MSID=BJ20111748 FGF21 gene as a target gene for ATF4 and we have localized two conserved ATF4 binding sequences in the 5’ regulatory region of the human FGF21 gene, which are responsible for the ATF4-dependent transcriptional activation of this gene. These results add FGF21 gene induction to the transcriptional program initiated by increased levels of ATF4 and offer a new mechanism for the induction of the FGF21 gene expression under nutrient deprivation.]]> A De Sousa-Coelho, P F. Marrero, D Haro 2012-01-11T12:04:15Z doi:10.1042/BJ20111748 Portland Press Limited 2012-01-11 BJ Metabolism http://www.biochemj.org/bj/imps/refer.htm?MSID=BJ20111817 J Mittag, T Behrends, K Nordström, J Anselmo, B Vennström, L Schomburg 2012-01-06T11:15:00Z doi:10.1042/BJ20111817 Portland Press Limited 2012-01-06 BJ Gene http://www.biochemj.org/bj/imps/refer.htm?MSID=BJ20111648 ca. 2-fold. We conclude that dicarbonyl stress is countered by up-regulation of glyoxalase-1 in the Nrf2 stress responsive system, protecting protein and DNA from increased damage and preserving cell function.]]> M Xue, N Rabbani, H Momiji, P Imbasi, M Anwar, N Kitteringham, K Park, T Souma, T MORIGUCHI, M Yamamoto, P J. Thornalley 2011-12-22T10:54:17Z doi:10.1042/BJ20111648 Portland Press Limited 2011-12-22 BJ Metabolism http://www.biochemj.org/bj/imps/refer.htm?MSID=BJ20111768 R Jauch, C Keow Leng Ng, K Narasimhan, P R Kolatkar 2011-12-19T14:39:29Z doi:10.1042/BJ20111768 Portland Press Limited 2011-12-19 BJ Structure http://www.biochemj.org/bj/imps/refer.htm?MSID=BJ20111284 o-a subunit of F₁F_o-ATP synthase (F₁F_o) is a highly hydrophobic protein with five putative transmembrane helices and it plays a central role in H⁺-translocation that is coupled with ATP synthesis/hydrolysis. Here, we show that F_o-a subunit produced by the in vitro protease-free protein synthesis system (PURE system) is integrated into a preformed F_o-a-less F₁F_o complex in the Escherichia coli membrane vesicles and in liposomes. The resulting F₁F_o has H⁺-coupled ATP synthesis/hydrolysis activity that is approximately half of that of the native F₁F_o. By using this procedure, we analyzed five mutations of F₁F_o, where the conserved residues in F_o-a subunit (N90, D112, R169, N173, and Q217) were individually replaced with alanine. All of the mutant F_o-a subunits were successfully incorporated into F₁F_o, showing the advantage over conventional expression in E. coli by which three (N90A, D112A, and Q217A) mutant F_o-a subunits were not found in F₁F_o. A mutant N173A retained full activity and mutants D112A and Q217A weak but detectable activity. No activity was observed for mutants of R169A, as reported, and N90A. N90 is located in the middle of putative second transmembrane helix and likely to play an important role in H⁺-translocation. This work exemplifies that the PURE system provides an alternative approach when in vivo expression of membraneous components in protein complexes turns out to be difficult.]]> Y Kuruma, T Suzuki, S Ono, M Yoshida, T Ueda 2011-12-14T12:07:26Z doi:10.1042/BJ20111284 Portland Press Limited 2011-12-14 BJ Energy http://www.biochemj.org/bj/imps/refer.htm?MSID=BJ20111739 DREB2A which lacks the interaction domain accumulates during heat stress and senescence. In addition RCD1 is rapidly degraded during heat stress, thus our results suggest that removal of RCD1 protein or the loss of the interaction domain in DREB2A appears to be required for proper DREB2A function under stress conditions.]]> J P Vainonen, P Jaspers, M Wrzaczek, A Lamminmäki, R A Reddy, L Vaahtera, M Brosché, J Kangasjärvi 2011-12-12T16:51:43Z doi:10.1042/BJ20111739 Portland Press Limited 2011-12-12 BJ Plant http://www.biochemj.org/bj/imps/refer.htm?MSID=BJ20111502 Glyt1 gene as a model system to investigate where HMGN proteins are bound across the locus in vivo, and to study how the two HMGN3 splice variants affect histone modifications and gene expression. We demonstrate that HMGN1, HMGN2, HMGN3a and HMGN3b are bound across the Glyt1 gene locus and surrounding regions, and are not enriched more highly at the promoter or putative enhancer. We conclude that the peaks of H3K4me3 and H3K9ac at the active Glyt1a promoter do not play a major role in recruiting HMGN proteins. HMGN3a/b binding leads to increased H3K14 acetylation and stimulates Glyt1a expression, and but does not alter the levels of H3K4me3 or H3K9ac enrichment. Acetylation assays show that HMGN3a stimulates the ability of PCAF to acetylate nucleosomal H3 in vitro, whereas HMGN3b does not. We propose a model where HMGN3a/b–stimulated H3K14 acetylation across the bodies of large genes like Glyt1 can lead to more efficient transcription elongation and increased mRNA production.]]> G Barkess, Y Postnikov, C D Campos, S Mishra, G Mohan, S Verma, M Bustin, K L West 2011-12-12T16:16:08Z doi:10.1042/BJ20111502 Portland Press Limited 2011-12-12 BJ Gene http://www.biochemj.org/bj/imps/refer.htm?MSID=BJ20111745 A K Panigrahi, N Zhang, S K Otta, D Pati 2011-12-07T12:10:00Z doi:10.1042/BJ20111745 Portland Press Limited 2011-12-07 BJ Cell http://www.biochemj.org/bj/imps/refer.htm?MSID=BJ20111322 Synopsis Aldo-keto reductase1B10 (AKR1B10) is overexpressed in live and lung cancer and plays a critical role in tumor development and progression through promoting lipogenesis and eliminating cytotoxic carbonyls. AKR1B10 is a secretory protein and potential tumor marker. However, little is known about the regulatory mechanism of AKR1B10 expression. This study showed that AKR1B10 is induced by mitogens epidermal growth factor (EGF) and insulin through the activator protein-1 (AP-1) signaling pathway. In human hepatocellular carcinoma cells (HepG2 and Hep3B), EGF (50ng/ml) and insulin (10nM) stimulated endogenous AKR1B10 expression and promoter activity. In the AKR1B10 promoter, a putative AP-1 element was found at -222 to -212bp. Deletion or mutations of this AP-1 element abrogated the basal promoter activity and response to EGF and AP-1 proteins. This AP-1 element bound to nuclear proteins extracted from HepG2 cells, and this binding was stimulated by EGF and insulin in a dose-dependent manner. Chromatin immunoprecipitation showed that AP-1 proteins c-Fos and c-Jun were predominant factors bound to the AP-1 consensus, followed by JunD and then JunB. The same order was followed in the stimulation of endogenous AKR1B10 expression by AP-1 proteins. Furthermore, c-Fos shRNA and AP-1 inhibitors/antagonists (U0126 and Tanshinone IIA) inhibited the endogenous AKR1B10 expression and promoter activity in HepG2 cells cultured in vitro or inoculated subcutaneously in nude mice. U0126 also inhibited AKR1B10 expression induced by EGF. Together these data suggest that AKR1B10 is upregulated by EGF and insulin through the AP-1 mitogenic signaling and may be implicated in hepatocarcinogenesis.]]> Z Liu, R Yan, A Al-salman, Y Shen, Y Bu, J Ma, D Luo, C Huang, Y Jiang, A Wilber, Y Mo, M Huang, Y Zhao, D Cao 2011-12-02T16:18:34Z doi:10.1042/BJ20111322 Portland Press Limited 2011-12-02 BJ Signal http://www.biochemj.org/bj/imps/refer.htm?MSID=BJ20111271 1-acetylpolyamine oxidase. We have demonstrated that long chain polyamine analogues, the oligoamines, are inhibitors of LSD1. Here we report the synergistic effects of specific oligoamines in combination with 2-difluoromethylornithine (DFMO), an inhibitor of ornithine decarboxylase, in human colorectal cancer cells. DFMO treatment depletes natural polyamines and increases the uptake of exogenous polyamines. The combination of oligoamines and DFMO results in a synergistic re-expression of aberrantly silenced tumor suppressor genes, including the secreted frizzled-related protein 2 (SFRP2) gene, which encodes a Wnt signaling pathway antagonist and plays an anti-tumorigenic role in colorectal cancer. The treatment-induced re-expression of SFRP2 is associated with increased H3K4me2 in the gene promoter. The combination of LSD1-inhibiting oligoamines and DFMO represents a novel approach to epigenetic therapy of cancer.]]> Y Wu, N Steinbergs, T Murray-Stewart, L J. Marton, R A Casero Jr. 2011-12-02T10:55:23Z doi:10.1042/BJ20111271 Portland Press Limited 2011-12-02 BJ Disease http://www.biochemj.org/bj/imps/refer.htm?MSID=BJ20111517 0/G₁ arrest. We also confirmed that miR-17 exerted this function by directly targeting RND3 in vitro and that the expression of miR-17 was negatively correlated with that of RND3 in CRC tissues and CRC cells. Moreover, miR-17 inhibition led to tumor growth suppression and up-regulation of RND3 expression in a nude mouse xenograft model. RND3 expression was found significantly lower in CRC tissues than in normal tissues and adenomas, indicating RND3 may act as a tumor suppressor gene in CRC. In conclusion, our study suggests that miR-17 plays an important role in CRC carcinogenesis by targeting RND3 and may be a therapeutic agent for CRC.]]> H Luo, J Zou, Z Dong, Q Zeng, D Wu, L Liu 2011-12-01T15:34:18Z doi:10.1042/BJ20111517 Portland Press Limited 2011-12-01 BJ Disease