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

[EX Q]: Polycomb gene silencing requires histone methyltransferase activity of Polycomb repressive complex 2 (PRC2), which methylates lysine 27 of histone H3. Information on how PRC2 works is limited by lack of structural data on the catalytic subunit, Enhancer of zeste (E(Z)), and the paucity of E(z) mutant alleles that alter its SET domain. Here we analyze missense alleles of Drosophila E(z), selected for molecular study because of their dominant genetic effects. Four missense alleles identify key E(Z) SET domain residues, and a fifth is located in the adjacent CXC domain. Analysis of mutant PRC2 complexes in vitro, and H3-K27 methylation in vivo, shows that each SET domain mutation disrupts PRC2 histone methyltransferase. Based on known SET domain structures, the mutations likely affect either the lysine-substrate binding pocket, the binding site for the adenosylmethionine methyl donor, or a critical tyrosine predicted to interact with the substrate lysine epsilon-amino group. In contrast, the CXC mutant retains catalytic activity, Lys-27 specificity, and trimethylation capacity. Deletion analysis also reveals a functional requirement for a conserved E(Z) domain N-terminal to CXC and SET. These results identify critical SET domain residues needed for PRC2 enzyme function, and they also emphasize functional inputs from outside the SET domain.
[EX A]: What is the characteristic domain of histone methyltransferases?

[EX Q]: Rigel Pharmaceuticals Inc is developing fostamatinib, a prodrug of the spleen tyrosine kinase (Syk) inhibitor R-406, for the potential treatment of autoimmune diseases such as rheumatoid arthritis (RA), idiopathic thrombocytopenic purpura (ITP) and B-cell lymphomas. Syk is a key mediator of Fc and B-cell receptor signaling in inflammatory cells, such as B-cells, mast cells, macrophages and neutrophils. Preclinical studies of R-406 or fostamatinib demonstrated a significant reduction in major inflammatory mediators such as TNFalpha, IL-1, IL-6 and IL-18, leading to reduced inflammation and bone degradation in models of RA. In a phase II clinical trial, fostamatinib treatment effectively improved American College of Rheumatology response rates in patients with RA. Preclinical studies and phase II trials also suggested the potential of using fostamatinib for the treatment of ITP and B-cell lymphomas, by increasing platelet counts and inducing response rates, respectively. Fostamatinib is orally bioavailable and was well tolerated in phase I and II trials, with the most common side effect being gastrointestinal symptoms. At the time of publication, phase II trials for fostamatinib were ongoing in patients with RA, ITP and B-cell lymphomas. The Syk inhibitor appears to be a promising therapeutic for immunological diseases, but further data are required to establish the efficacy and long-term safety of the drug in humans.
[EX A]: Which enzyme is inhibited by a drug fostamatinib?

[EX Q]: Stories in Boxes: Britain performing artist Bobby Baker will present Box Story to conclude the UK performing Arts Festival. Her performances cover various aspects of life: including health, shopping, and educating children. She explores these themes with originality and "outside the square". Time: 7:30 pm, December 3-5 Place: North Theater, Beibingmasi Lane, Jiaodaokou, Dongcheng District Tel: 8602-4898 Elvis Story: Le Caoitole De Quebee will bring its production The Elvis Storyto Beijing audiences this month. This remarkable musical production relates the best moments of Elvis Preeley's life and his career. The show is a musical reconstitution of the life of a singer who revolutionized American popular music and become the most famous rock star of the 20th century. Time: 7:30 pm, November 25-28 Place: Poly Theater, Dongsishitiao Tel: 6506-5343, 6413-1321 Soldier's musical: A Soldier's Diary, a Chinese musical describing the life of contemporary soldiers in China, is to be staged for 12 performances by the Song and Dance Essembles of the Political of the Chinese People Liberation Army . Time: 7:30 pm, November 29-December15 Place: China Theatre, Xisanhuan Beilu, Handian District Tel: 6843-0560 Social tolerance: The Italian opera Pagliacci, by Ruggero Leoneavallo ( 1856--1919), is to premiere , performed by Chinese opera singers from China's Central Opera Theatre. A violent opera exploring the limits of social tolerance, the opera premiered in 1892 and gained popularity throughout Europe and America. Within two years, it had been translated into all major European languages including Swedish, Serbo-Croatian and Hebrew. Leoneavallo was a prolific writer, yet none of his other works ever matched the popularity of this opera. Chinese vocal artists include Huang Yuefeng, Wang Feng, Sun Xiewei, Gao Lei and Shen Na, Li Wei is to conduct.. Time: 7:30 pm, November 27 Place: Peking University Concert Hall, Peking University Tel: 6275-1278, 6551-4787
[EX A]:
Which performance covers the life of contemporary soldiers in China?