Chemical RNA modifications are central features of epitranscriptomics, highlighted by the discovery of modified ribonucleosides in mRNA and exemplified by the critical roles of RNA modifications in normal physiology and disease. Despite a resurgent interest in these modifications, the biochemistry of 3-methylcytidine (mC) formation in mammalian RNAs is still poorly understood. However, the recent discovery of as the second gene responsible for mC presence in RNA in fission yeast raises the possibility that multiple enzymes are involved in mC formation in mammals as well. Here, we report the discovery and characterization of three distinct mC-contributing enzymes in mice and humans. We found that methyltransferase-like (METTL) 2 and 6 contribute mC in specific tRNAs and that METTL8 only contributes mC to mRNA. MS analysis revealed that there is an ∼30-40% and ∼10-15% reduction, respectively, in and null-mutant cells, of mC in total tRNA, and primer extension analysis located METTL2-modified mC at position 32 of tRNA isoacceptors and tRNA We also noted that METTL6 interacts with seryl-tRNA synthetase in an RNA-dependent manner, suggesting a role for METTL6 in modifying serine tRNA isoacceptors. , however, modified only mRNA, as determined by biochemical and genetic analyses in null-mutant mice and two human mutant cell lines. Our findings provide the first evidence of the existence of mC modification in mRNA, and the discovery of METTL8 as an mRNA mC writer enzyme opens the door to future studies of other mC epitranscriptomic reader and eraser functions.

SummaryTransforming growth factor b-activated kinase 1 (TAK1) is a key regulator of the innate immunity and the proinflammatory signaling pathway. In response to interleukin-1, tumor necrosis factor-a, and toll-like receptor agonists, it mediates the activation of the nuclear factor jB (NF-jB), c-Jun N-terminal kinase (JNK), and p38 pathways. In addition, TAK1 plays a central role in adaptive immunity, in which it mediates signaling from T-and B-cell receptors. This review will focus on recent developments and also examine the regulation of TAK1 in response to a diverse range of other stimuli including DNA damage, transforming growth factor-b, Wnt, osmotic stress, and hypoxia.2012 IUBMB IUBMB Life, 64(10): [825][826][827][828][829][830][831][832][833][834] 2012

Mammalian Pellino isoforms are phosphorylated by IRAK (interleukin receptor associated kinase) 1/IRAK4 in vitro, converting them into active E3 ubiquitin ligases. In the present paper we report a striking enhancement in both transcription of the gene encoding Pellino 1 and Pellino 1 protein expression when murine BMDMs (bone-marrow-derived macrophages) are stimulated with LPS (lipopolysaccharide) or poly(I:C). This induction occurs via a TRIF [TIR (Toll/interleukin-1 receptor)-domain-containing adaptor-inducing interferon-β]-dependent IRAK-independent pathway and is prevented by inhibition of the IKK [IκB (inhibitor of nuclear factor κB) kinase]-related protein kinases, TBK1 {TANK [TRAF (tumour-necrosis-factor-receptor-associated factor)-associated nuclear factor κB activator]-binding kinase 1} and IKKε. Pellino 1 is not induced in IRF3 (interferon regulatory factor 3)-/- BMDMs, and its induction is only reduced slightly in type 1 interferon receptor-/- BMDMs, identifying Pellino 1 as a new IRF3-dependent gene. We also identify Pellino 1 in a two-hybrid screen using IKKε as bait, and show that IKKε/TBK1 activate Pellino 1 in vitro by phosphorylating Ser76, Thr288 and Ser293. Moreover, we show that the E3 ligase activity of endogenous Pellino 1 is activated in LPS- or poly(I:C)-stimulated macrophages. This occurs more rapidly than the increase in Pellino 1 mRNA and protein expression, is prevented by the inhibition of IKKε/TBK1 and is reversed by phosphatase treatment. Thus IKKε/TBK1 mediate the activation of Pellino 1's E3 ligase activity, as well as inducing the transcription of its gene and protein expression in response to TLR3 and TLR4 agonists.

No abstract

IntroductionNonalcoholic steatohepatitis (NASH) is largely driven by the dysregulation of liver metabolism and inflammation. Bile acids and their receptor Farnesoid X receptor (FXR) play a critical role in the disease development. Here, we investigated whether INT-767, the newly-identified dual FXR/TGR5 agonist, can protect rat from liver injury during NASH.Materials and methodsNASH model was established by feeding the male SD rats with high-fat diet for 16 weeks. INT-767 was given by gavage to NASH rats from week 13 to week 16. At the end of 16 weeks, liver and serum were harvested, and bile acids, glucose and lipid metabolism, liver injury and histological features were evaluated.ResultsINT-767 treatment significantly alleviates high-fat caused liver damage characterized with lipid accumulation and hepatic infiltration of immune cells. INT-767 robustly restores the lipid, glucose metabolism to normal level, attenuates insulin resistance through upregulating FXR level and reverting the dysregulation of its target genes in liver metabolism. Molecularly INT-767 also attenuates the pro-inflammatory response by suppression of TNF-α and NF-κB signaling pathway.ConclusionINT-767 may be an attractive candidate for a potential novel strategy on the treatment of NASH.

This paper describes and analyses the performance of a novel feature extraction technique for the recognition of segmented/cursive characters that may be used in the context of a segmentation-based handwritten word recognition system. The Modified Direction Feature (MDF) extraction technique builds upon the Direction Feature (DF) technique proposed previously that extracts direction information from the structure of character contours. This principal was extended so that the direction information is integrated with a technique for detecting transitions between background and foreground pixels in the character image. In order to improve on the DF extraction technique, a number of modifications were undertaken. With a view to describe the character contour more effectively, a redesign of the direction number determination technique was performed. Also, an additional global feature was introduced to improve the recognition accuracy for those characters that were most frequently confused with patterns of similar appearance. MDF was tested using a neural network-based classifier and compared to the DF and Transition Feature (TF) extraction techniques. MDF outperformed both DF and TF techniques using a benchmark dataset and compared favourably with the top results in the literature. A recognition accuracy of above 89% is reported on characters from the CEDAR dataset.

Characterising the activated oncogenic signalling that leads to advanced breast cancer is of clinical importance. Here, we showed that SET domain, bifurcated 1 (SETDB1), a histone H3 lysine 9 methyltransferase, is aberrantly expressed and behaves as an oncogenic driver in breast cancer. SETDB1 enhances c-MYC and cyclin D1 expression by promoting the internal ribosome entry site (IRES)-mediated translation of MYC/CCND1 mRNA, resulting in prominent signalling of c-MYC to promote cell cycle progression, and provides a growth/self-renewal advantage to breast cancer cells. The activated c-MYC-BMI1 axis is essential for SETDB1-mediated breast tumourigenesis, because silencing of either c-MYC or BMI1 profoundly impairs the enhanced growth/colony formation conferred by SETDB1. Furthermore, c-MYC directly binds to the SETDB1 promoter region and enhances its transcription, suggesting a positive regulatory interplay between SETDB1 and c-MYC. In this study, we identified SETDB1 as a prominent oncogene and characterised the underlying mechanism whereby SETDB1 drives breast cancer, providing a therapeutic rationale for targeting SETDB1-BMI1 signalling in breast cancer. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

The protein kinase transforming-growth-factor-bactivated kinase-1 (TAK1) is a key regulator in the pro-inflammatory signaling pathway and is activated by tumor necrosis factor-a, interleukin-1 (IL-1) and lipopolysaccharide (LPS). We describe the identification of TAK1 as a client protein of the 90 kDa heat-shock protein (Hsp90)/cell division cycle protein 37 (Cdc37) chaperones. However, Hsp90 is not required for the activation of TAK1 as short exposure to the Hsp90 inhibitor, 17-(allylamino)-17-demethoxygeldanamycin (17-AAG) did not affect its activation by LPS or IL-1. Prolonged treatment of cells with 17-AAG inhibits Hsp90 and downregulates TAK1. Our results suggest that Hsp90 is required for the folding and stability of TAK1 but is displaced and no longer required when TAK1 is complexed to TAK1-binding protein-1 (TAB1).