The HIV-1 long terminal repeat contains an unusual element that induces the synthesis of short RNAs from various mRNA and snRNA promoters

We describe an unusual element that activates the synthesis of short transcripts from a wide variety of mRNA and small nuclear RNA (snRNA) promoters, including the U6 RNA polymerase III promoter. This inducer of short transcripts (IST) is located between positions -5 and +82 relative to the cap site in the HIV-1 LTR. In the presence of IST, the total transcriptional activity of the different promoters is greatly increased, but the resulting additional RNA molecules are short, ending around position +60. IST is not the RNA target (TAR) for Tat trans-activation; however, because it relies entirely on cellular factors for activity, IST may serve to provide abundant RNA targets for Tat trans-activation without a requirement for full-length viral mRNA expression

Hypothalamic arcuate nucleus glucokinase regulates insulin secretion and glucose homeostasis

Aims Glucokinase (GK) serves as a glucose sensor in several tissues including glucose‐sensitive neurons of the arcuate nucleus within the hypothalamus. We have previously demonstrated a role for arcuate GK in the regulation of food and glucose intake. However, its role in the regulation of glucose homeostasis is less clear. We therefore sought to investigate the role of arcuate GK in the regulation of glucose homeostasis. Materials and Methods Recombinant adeno‐associated virus expressing either GK or an antisense GK construct was used to alter GK activity specifically in the hypothalamic arcuate nucleus. GK activity in this nucleus was also increased by stereotactic injection of the GK activator, compound A. The effect of altered arcuate nucleus GK activity on glucose homeostasis was subsequently investigated using glucose and insulin tolerance tests. Results Increased GK activity specifically within the arcuate nucleus increased insulin secretion and improved glucose tolerance in rats during oral glucose tolerance tests. Decreased GK activity in this nucleus reduced insulin secretion and increased glucose levels during the same tests. Insulin sensitivity was not affected in either case. The effect of arcuate nucleus glucokinase was maintained in a model of type 2 diabetes. Conclusions These results demonstrate a role for arcuate nucleus GK in systemic glucose homeostasis

Effects of corticosterone within the hypothalamic arcuate nucleus on food intake and body weight in male rats

Background Obesity is a major cause of morbidity and mortality. Few weight-reducing medications are available, and these have limited efficacy. Cushing’s Syndrome (caused by elevated glucocorticoid levels) and obesity have similar metabolic features. Though circulating glucocorticoid levels are not elevated in obesity, tissue-specific glucocorticoid levels have been implicated in the development of the metabolic phenotype of obesity. Tissue glucocorticoid levels are regulated by 11β-hydroxysteroid dehydrogenase type1 (11βHSD1), which increases the local concentration of active glucocorticoids by production of corticosterone from 11-dehydrocorticosterone. 11βHSD1 is expressed in the hypothalamic arcuate nucleus (ARC), a major weight and appetite-regulating centre, and therefore represents a target for novel anti-obesity therapeutic agents. Objectives To investigate the effect of chronic alterations of ARC corticosterone levels (mediated by 11βHSD1) on food intake and body weight in adult male rats. Methods Recombinant adeno-associated virus bearing sense 11βHSD1 (rAAV-S11βHSD1) and small interfering 11βHSD1 (rAAV-si11βHSD1) respectively were stereotactically injected into the ARC (bilaterally) of adult male Wistar rats. rAAV-GFP was injected into control groups of male Wistar rats. Food intake and body weight were measured three times a week for 70 days. Terminal brain, plasma and intrascapular brown adipose tissue (iBAT) samples were taken for measurement of mRNA expression and hormone levels. Results Compared to controls, rAAV-S11βHSD1 injection resulted in higher ARC corticosterone levels, hyperphagia and increased weight gain. Conversely, rAAV-si11βHSD1 injection (compared to controls) resulted in lower ARC corticosterone levels, higher iBAT uncoupling protein-1 mRNA expression and less weight gain despite similar food intake. Conclusions Therefore, ARC corticosterone, regulated by 11βHSD1, may play a role in food intake and body weight regulation. These data have important implications for the development of centrally-acting 11βHSD1 inhibitors, which are currently being developed for the treatment of obesity, metabolic disorders and other conditions

The effects of kisspeptin on β-cell function, serum metabolites and appetite in humans

Aims: To investigate the effect of kisspeptin on glucose-stimulated insulin secretion and appetite in humans. Materials and methods: In 15 healthy men (age: 25.2 ± 1.1 years; BMI: 22.3 ± 0.5 kg m−2), we compared the effects of 1 nmol kg−1 h−1 kisspeptin versus vehicle administration on glucose-stimulated insulin secretion, metabolites, gut hormones, appetite and food intake. In addition, we assessed the effect of kisspeptin on glucose-stimulated insulin secretion in vitro in human pancreatic islets and a human β-cell line (EndoC-βH1 cells). Results: Kisspeptin administration to healthy men enhanced insulin secretion following an intravenous glucose load, and modulated serum metabolites. In keeping with this, kisspeptin increased glucose-stimulated insulin secretion from human islets and a human pancreatic cell line in vitro. In addition, kisspeptin administration did not alter gut hormones, appetite or food intake in healthy men. Conclusions: Collectively, these data demonstrate for the first time a beneficial role for kisspeptin in insulin secretion in humans in vivo. This has important implications for our understanding of the links between reproduction and metabolism in humans, as well as for the ongoing translational development of kisspeptin-based therapies for reproductive and potentially metabolic conditions

Nuclear Factor 90(NF90) targeted to TAR RNA inhibits transcriptional activation of HIV-1

<p>Abstract</p> <p>Background</p> <p>Examination of host cell-based inhibitors of HIV-1 transcription may be important for attenuating viral replication. We describe properties of a cellular double-stranded RNA binding protein with intrinsic affinity for HIV-1 TAR RNA that interferes with Tat/TAR interaction and inhibits viral gene expression.</p> <p>Results</p> <p>Utilizing TAR affinity fractionation, North-Western blotting, and mobility-shift assays, we show that the C-terminal variant of nuclear factor 90 (NF90ctv) with strong affinity for the TAR RNA, competes with Tat/TAR interaction <it>in vitro</it>. Analysis of the effect of NF90ctv-TAR RNA interaction <it>in vivo </it>showed significant inhibition of Tat-transactivation of HIV-1 LTR in cells expressing NF90ctv, as well as changes in histone H3 lysine-4 and lysine-9 methylation of HIV chromatin that are consistent with the epigenetic changes in transcriptionally repressed gene.</p> <p>Conclusion</p> <p>Structural integrity of the TAR element is crucial in HIV-1 gene expression. Our results show that perturbation Tat/TAR RNA interaction by the dsRNA binding protein is sufficient to inhibit transcriptional activation of HIV-1.</p

Characterization of the inducer of short transcripts, a human immunodeficiency virus type 1 transcriptional element that activates the synthesis of short RNAs.

The inducer of short transcripts, or IST, is an unusual transcriptional element located downstream of the human immunodeficiency virus type 1 (HIV-1) promoter. IST activates HIV-1 transcription, but the resulting RNAs are short and end at approximately position +59. IST, therefore, appears to promote the formation of transcription complexes that are unable to elongate efficiently. This activity contrasts with that of TAR, the target for Tat trans-activation, which upon binding of the viral protein Tat promotes the formation of transcription complexes capable of efficient elongation through the entire viral genome. We have localized and characterized the IST element. Our results indicate that IST is located mainly between positions -5 and +26, although the sequences from positions +40 to +59 also contribute to IST activity. Unlike TAR, which is an RNA element, IST appears to be a DNA element. Thus, the HIV-1 R region is a complex regulatory region with RNA and DNA elements that promote the formation of transcription complexes with different elongation properties

A review of construction waste data and reporting systems used in Australia

The construction industry is well recognised for the generation of a significant amount of waste which in turn has led the management of waste data as an important task of waste management. Waste data is essential not only for promoting effective waste management practices but also for the development and implementation of effective waste policies, legislations, and national standards. This paper aims to evaluate and understand the different waste data and reporting systems used in Australia. The outcomes of this study are based on the literature analysis of secondary data. The review revealed that most of the states and territories use a centralised waste data collection and reporting system and the use of such a system varies between states and territories due to the variation in waste definition, classification and estimation practices. This, in turn, hinders the development of effective waste management policies, relevant waste management programmes and as well as the establishment of domestic and international market platforms for recovered waste materials, attracting new circular business models. Consequently, the results inform the unyielding need to develop an efficient waste data management system. Blockchain as a decentralised data management technology could considerably improve the waste data management practices including waste data collection, reporting, and auditing and contribute to driving a shift towards the circular economy through circularity of waste information. Future research is aimed to develop a decentralised waste data management system as part of the development of a blockchaintechnology based waste trading platform