Vertebrate segmentation is regulated by the “segmentation clock”, which drives cyclic expression of several genes in the caudal presomitic mesoderm (PSM). One such gene is Lunatic fringe (Lfng), which encodes a modifier of Notch signalling, and which is also expressed in a stripe at the cranial end of the PSM, adjacent to the newly forming somite border. We have investigated the functional requirements for these modes of Lfng expression during somitogenesis by generating mice in which Lfng is expressed in the cranial stripe but strongly reduced in the caudal PSM, and find that requirements for Lfng activity alter during axial growth. Formation of cervical, thoracic and lumbar somites/vertebrae, but not sacral and adjacent tail somites/vertebrae, depends on caudal, cyclic Lfng expression. Indeed, the sacral region segments normally in the complete absence of Lfng and shows a reduced requirement for another oscillating gene, Hes7, indicating that the architecture of the clock alters as segmentation progresses. We present evidence that Lfng controls dorsal-ventral axis specification in the tail, and also suggest that Lfng controls the expression or activity of a long-range signal that regulates axial extension.

Diazaborine treatment of yeast cells was shown previously to cause accumulation of aberrant, 3-elongated mRNAs. Here we demonstrate that the drug inhibits maturation of rRNAs for the large ribosomal subunit. Pulse-chase analyses showed that the processing of the 27S pre-rRNA to consecutive species was blocked in the drug-treated wild-type strain. The steady-state level of the 7S pre-rRNA was clearly reduced after short-term treatment with the inhibitor. At the same time an increase of the 35S pre-rRNA was observed. Longer incubation with the inhibitor resulted in a decrease of the 27S precursor. Primer extension assays showed that an early step in 27S pre-rRNA processing is inhibited, which results in an accumulation of the 27SA2 pre-rRNA and a strong decrease of the 27SA3, 27SB1L, and 27SB1S precursors. The rRNA processing pattern observed after diazaborine treatment resembles that reported after depletion of the RNA binding protein Nop4p/ Nop77p. This protein is essential for correct pre-27S rRNA processing. Using a green fluorescent protein-Nop4 fusion, we found that diazaborine treatment causes, within minutes, a rapid redistribution of the protein from the nucleolus to the periphery of the nucleus, which provides a possible explanation for the effect of diazaborine on rRNA processing.Translation of mRNA in the cytoplasm relies on the ribosome. While the principal steps in initiation and elongation of protein synthesis were uncovered in the middle of the last century, details of the biogenesis of the ribosome itself remained elusive. However, the development of novel techniques in affinity purification and refined techniques of protein identification by mass spectrometry within the last several years provided novel insights into the steps of assembly of the ribosomal subunits and how they are coordinated with the processing of the rRNA precursors (for recent reviews see references 15 and 47). Much of this detailed knowledge was worked out in the baker's yeast, Saccharomyces cerevisiae. This organism constitutes a simple model for the reaction sequence occurring in more complex eukaryotic cells.While the 5S rRNA is transcribed by RNA polymerase III, the 18S, 25S, and 5.8S rRNAs are transcribed as a single precursor molecule by RNA polymerase I. The primary transcript is cotranscriptionally processed at its 3Ј external transcribed spacer (ETS) end into the 35S pre-rRNA (26). The rRNAs for both the large and the small subunits are then generated from the 35S pre-rRNA by several subsequent processing events. In the first two processing steps for the 35S rRNA, the 5Ј ETS is successively removed by endonucleolytic cleavages at positions A0 and A1. The following step, which separates the rRNA precursors for the two ribosomal subunits, is a cleavage reaction at position A2 in internal transcribed spacer 1 (ITS1) located between the 18S and 5.8S rRNAs (23,27). This cleavage reaction results in the release of the 20S pre-rRNA, which matures in the cytoplasm to the 18S rRNA present in the small subunit of the ribosome ...

Radiotherapy of the left breast in DIBH using a SS could easily be incorporated into daily routine and is associated with significant dose reduction to the heart and IL.

Non-steroidal anti-inflammatory drug (NSAID)-exacerbated respiratory disease (N-ERD) comprises the triad of chronic rhinosinusitis with nasal polyps, asthma, and intolerance to NSAIDs. Dupilumab treatment, targeting the IL-4 receptor alpha, significantly reduces polyp burden as well as asthma symptoms. Here we aimed to investigate the effect of dupilumab on aspirin intolerance, burden of disease, as well as on nasal cytokine profiles in patients suffering from N-ERD. In this open-label trial, adult patients with confirmed N-ERD were treated with dupilumab for six months. Clinical parameters (e.g., total polyp scores, quality of life questionnaires, smell test, spirometry), oral aspirin provocation testing, blood, nasal and urine sampling were monitored up to six months after starting dupilumab therapy at regular intervals. Of the thirty-one patients included in the study, thirty completed both aspirin provocation testing. After six months of treatment with dupilumab, 23.3% (n=7/30) of patients developed complete aspirin tolerance and an additional 33.3% of patients (n=10/30) tolerated higher doses. Polyp burden was significantly reduced (total polyp score: −2.68±1.84, p<0.001) and pulmonary symptoms (asthma control test: +2.34±3.67, p<0.001), as well as olfactory performance improved (UPSIT: +11.16±9.54, p<0.001) in all patients after therapy. Patients with increased aspirin tolerance showed a significant decrease in urine leukotriene E4 levels and their improvement in clinical parameters was associated with the reduction of eotaxin-1, CCL17, IL-5, IL-17A and IL-6. 57% of N-ERD patients tolerated higher doses of aspirin under dupilumab therapy.

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