In Vivo Expression of MHC Class I Genes Depends on the Presence of a Downstream Barrier Element

Regulation of MHC class I gene expression is critical to achieve proper immune surveillance. In this work, we identify elements downstream of the MHC class I promoter that are necessary for appropriate in vivo regulation: a novel barrier element that protects the MHC class I gene from silencing and elements within the first two introns that contribute to tissue specific transcription. The barrier element is located in intergenic sequences 3′ to the polyA addition site. It is necessary for stable expression in vivo, but has no effect in transient transfection assays. Accordingly, in both transgenic mice and stably transfected cell lines, truncation of the barrier resulted in transcriptional gene silencing, increased nucleosomal density and decreased histone H3K9/K14 acetylation and H3K4 di-methylation across the gene. Significantly, distinct sequences within the barrier element govern anti-silencing and chromatin modifications. Thus, this novel barrier element functions to maintain transcriptionally permissive chromatin organization and prevent transcriptional silencing of the MHC class I gene, ensuring it is poised to respond to immune signaling

CHANGE DETECTION IN URBAN AREAS USING VERY HIGH SPATIAL RESOLUTION SATELLITE IMAGES: CASE STUDY IN BRUSSELS

Attempts are done to find possibilities of updating the Urban Information System (UrbIS) topographic data base thanks to VHR satellite images (IKONOS and QuickBird); this 1: 500 database over Brussels, Belgium is currently established and updated by photo restitution of large scale aerial photos. Because of the difference of scales between the database and the satellite images, but also because of the continuous nature of the kind of update, the analysis focuses only on roads, buildings and vegetation changes, the purpose being to have an alarm signal for important changes to concentrate the field work in between two flight campaigns. The techniques implemented are multi-temporal supervised classification, multitemporal non-supervised classification and post-classification change detection. These techniques are used as such and in GIS-based change detection. This latest is implemented with masks exported from information contained in the UrbIS database. The Multi-temporal classification is used with two VHR satellite images. The first step is a multi-temporal coloured composition. This allows us to visually detect important changes. The selected scheme for the supervised classification is divided in two set of classes

Angiotensin II enhances noradrenaline release from sympathetic nerves of the rat prostate via a novel angiotensin receptor: implications for the pathophysiology of benign prostatic hyperplasia

The renin-angiotensin system (RAS) is present in the human prostate and may be activated in benign prostatic hyperplasia (BPH), possibly contributing to the pathophysiology of this disorder by enhancing local sympathetic tone and cell growth. The functional role of the PAS in the prostate, however, is unknown. The present study was undertaken to determine whether angiotensin (Ang) II enhances sympathetic transmission in the prostate. The neuronal stores of the rat prostate were labelled with [H-3]noradrenaline (NA). Ang II and Ang I enhanced [H-3]NA release in a concentration-dependent manner. The Ang II receptor subtype 1 (AT(1) receptor) antagonist losartan and the AT(2) receptor antagonist PD123319 inhibited this facilitatory effect of Ang II and Ang I, whereas the other AT(2) receptor antagonist, CGP42112, was without effect. Bradykinin also increased [H-3]NA release, which was inhibited by the B-2 receptor antagonist Hoe140. The angiotensin-converting enzyme inhibitor captopril inhibited the effect of Ang I, but potentiated that of bradykinin. Interestingly, captopril alone produced an increase in [H-3]NA release which was inhibited by Hoe140. Losartan, but not PD123319 or CGP42112, inhibited [I-125]-Ang II binding in Chinese hamster ovary cells transfected with the AT(1a) or AT(1b) receptor. In contrast, in cells expressing the AT(2) receptor, PD123319 and CGP42112, but not losartan, inhibited [I-125] -Ang II binding. In conclusion, Ang II enhances the release of NA from sympathetic nerves of the rat prostate via a novel functional receptor distinct from the cloned AT(1a) AT(1b) or AT(2). These data provide direct evidence in support of a functional role for the local RAS in modulating sympathetic transmission in the prostate, which may have important implications for the pathophysiology of BPH