Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.

[Q]: Context: Colonel Muhammadu Abdullahi Wase (died June 1996) was military administrator of Kano State in Nigeria from December 1993 -- 
 Question: Which country is Muhammadu Abdullahi Wase a citizen of?
[A]: nigeria


[Q]: Context: Previous X-ray crystal structures have shown that linkers of five amino acid residues connecting pairs of chicken brain alpha-spectrin and human erythroid beta-spectrin repeats can undergo bending without losing their alpha-helical structure. To test whether bending at one linker can influence bending at an adjacent linker, the structures of two and three repeat fragments of chicken brain alpha-spectrin have been determined by X-ray crystallography. The structure of the three-repeat fragment clearly shows that bending at one linker can occur independently of bending at an adjacent linker. This observation increases the possible trajectories of modeled chains of spectrin repeats. Furthermore, the three-repeat molecule crystallized as an antiparallel dimer with a significantly smaller buried interfacial area than that of alpha-actinin, a spectrin-related molecule, but large enough and of a type indicating biological specificity. Comparison of the structures of the spectrin and alpha-actinin dimers supports weak association of the former, which could not be detected by analytical ultracentrifugation, versus strong association of the latter, which has been observed by others. To correlate features of the structure with solution properties and to test a previous model of stable spectrin and dystrophin repeats, the number of inter-helical interactions in each repeat of several spectrin structures were counted and compared to their thermal stabilities. Inter-helical interactions, but not all interactions, increased in parallel with measured thermal stabilities of each repeat and in agreement with the thermal stabilities of two and three repeats and also partial repeats of spectrin. 
 Question: Alpha-spectrin and beta-spectrin subunits form parallel or antiparallel heterodimers?
[A]: antiparallel


[Q]: Context: Chronic myeloid leukemia (CML) is a progressive and often fatal myeloproliferative disorder. The hallmark of CML is an acquired chromosomal translocation known as the Philadelphia chromosome (Ph) that results in the synthesis of the BCR-ABL fusion protein, a constitutively active tyrosine kinase (TK). The introduction of imatinib, a TK inhibitor (TKI) specific for BCR-ABL, was a major breakthrough in CML therapy. Although most patients respond to first-line imatinib therapy, some experience a loss of response (resistance) or require treatment discontinuation because of toxicity (intolerance). In patients for whom standard-dose imatinib therapy (400 mg/day) fails, imatinib dose escalation (600-800 mg/day) is a second-line option. However, high-dose imatinib is not an appropriate approach for patients experiencing drug toxicity, and there remain questions over the durability of responses achieved with this strategy. Alternative second-line options include the newer TKIs dasatinib and nilotinib. A substantial amount of long-term data for these agents is available. Although both are potent and specific BCR-ABL TKIs, dasatinib and nilotinib exhibit unique pharmacologic profiles and response patterns relative to different patient characteristics, such as disease stage and BCR-ABL mutational status. To optimize therapeutic benefit, clinicians should select treatment based on each patient's historical response, adverse event tolerance level, and risk factors. 
 Question: What tyrosine kinase, involved in a Philadelphia- chromosome positive chronic myelogenous leukemia, is the target of Imatinib (Gleevec)?
[A]:
bcr-abl