Given a context passage, generate a question from the passage such that its answer is shortest continous span from the passage.

Input: Consider Input: The TNF family member receptor activator for NF-B ligand (RANKL) and its receptors RANK and osteoprotegerin are key regulators of bone remodeling but also influence cellular functions of tumor and immune effector cells. In this work, we studied the involvement of RANK-RANKL interaction in NK cell-mediated immunosurveillance of acute myeloid leukemia (AML). Substantial levels of RANKL were found to be expressed on leukemia cells in 53 of 78 (68%) investigated patients. Signaling via RANKL into the leukemia cells stimulated their metabolic activity and induced the release of cytokines involved in AML pathophysiology. In addition, the immunomodulatory factors released by AML cells upon RANKL signaling impaired the anti-leukemia reactivity of NK cells and induced RANK expression, and NK cells of AML patients displayed significantly upregulated RANK expression compared with healthy controls. Treatment of AML cells with the clinically available RANKL Ab Denosumab resulted in enhanced NK cell anti-leukemia reactivity. This was due to both blockade of the release of NK-inhibitory factors by AML cells and prevention of RANK signaling into NK cells. The latter was found to directly impair NK anti-leukemia reactivity with a more pronounced effect on IFN- production compared with cytotoxicity. Together, our data unravel a previously unknown function of the RANK-RANKL molecule system in AML pathophysiology as well as NK cell function and suggest that neutralization of RANKL with therapeutic Abs may serve to reinforce NK cell reactivity in leukemia patients.

Output: To the ligand of which receptors does Denosumab (Prolia) bind?

Input: Consider Input: Selenocysteine, a selenium-containing analog of cysteine, is found in the prokaryotic and eukaryotic kingdoms in active sites of enzymes involved in oxidation-reduction reactions. Its biosynthesis and cotranslational insertion into selenoproteins is performed by an outstanding mechanism, implying the participation of several gene products. The tRNA(Sec) is one of these. In eukaryotes, its transcription mode by RNA polymerase III differs from that of classical tRNA genes, both at the level of the promoter elements and transcription factors involved. In addition, enhanced transcription is afforded by a newly characterized zinc finger activator. Not only transcription of the gene, but also the tRNA(Sec) itself is atypical since its 2D and 3D structures exhibit features which set it apart from classical tRNAs. Decoding of eukaryotic selenocysteine UGA codons requires a stem-loop structure in the 3'UTR of mRNAs, the selenocysteine insertion sequence (SECIS) element. Structure probing and sequence comparisons led us to propose a 2D structure model for the SECIS element, containing a novel RNA motif composed of four consecutive non-Watson-Crick base-pairs. A 3D model, rationalizing the accessibility data, was elaborated by computer modeling. It yields indicative or suggestive evidence for the role that could play some conserved residues and/or structural features in SECIS function. These might act as signals for interaction with SBP, the SECIS binding protein that we have characterized.

Output: What is the name of the stem loop present in the 3' end of genes encoding for selenoproteins?

Input: Consider Input: The Ehlers-Danlos syndromes (EDS) are a heterogeneous group of heritable connective tissue disorders characterised by joint hypermobility, involvement of skin and tissue fragility. The Villefranche criteria have simplified its diagnosis, which, however, remains difficult in children and young adults with vascular and hypermobile EDS as well as in patients without a positive family history. Diagnosis of vascular EDS is important for clinical follow-up, genetic counseling and prenatal diagnosis. We describe the biochemical and molecular-genetic diagnosis of vascular EDS. We describe five families with vascular EDS. Analysis of (pro)collagens obtained from cultured fibroblasts was done using SDS-PAGE. The structure and amounts of (pro)collagen I, III and V were determined by autoradioflourography. This was also done in 362 controls or patients without a diagnosis of vascular EDS. Molecular testing was done in Professor Anne de Paepe's laboratory in Belgium by sequencing of COL3A1. (Pro)collagen from all five patients with vascular EDS was abnormal by SDS-PAGE: intracellular retention, reduced secretion and overmodification of the a1 chains of (pro)collagen III. Molecular analysis revealed an abnormality of COL3A1 in all patients. Abnormalities of (pro)collagen III were not observed in patients without a diagnosis of vascular EDS. Among 90 patients with non-vascular EDS, one patient had an abnormality of collagen I. Biochemical analysis of (pro)collagen obtained from cultured fibroblasts is a good screening procedure for vascular EDS, but it is of limited value in non-vascular EDS. Molecular testing will disclose an abnormality of COL3A1 in many patients with abnormal (pro)collagen III on SDS-PAGE. The findings make precise genetic counselling and prenatal diagnosis possible in families with vascular EDS.
Output: What tissue is most affected in Ehlers-Danlos syndromes?