Given a passage, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

Ex Input:
The proteasome is a major cellular proteinase. Its activity is modulated by cellular oxidants. Hepatitis C core protein and ethanol exposure both cause enhanced oxidant generation. The aim was to investigate whether core protein, by its ability to generate oxidants, alters proteasome activity and whether these alterations are further affected by ethanol exposure.', 'These interactions were examined in Huh-7 cell lines that expressed inducible HCV core protein and/or constitutive cytochrome P450 2E1 (CYP2E1) and as purified components in a cell-free system. Chymotrypsin-like proteasome activity was measured fluorometrically.', 'Proteasome activity in core-positive 191-20 cells was 20% higher than that in core-negative cells and was enhanced 3-fold in CYP2E1-expressing L14 cells. Exposure of core-positive cells to glutathione ethyl ester, catalase, or the CYP2E1 inhibitor diallyl sulfide partially reversed the elevation of proteasome activity in core-positive cells, whereas ethanol exposure suppressed proteasome activity. The results indicate that proteasome activity was up-regulated by low levels of core-induced oxidative stress but down-regulated by high levels of ethanol-elicited stress. These findings were partially mimicked in a cell-free system. Addition of core protein enhanced the peptidase activity of purified 20S proteasome containing the proteasome activator PA28 and was further potentiated by addition of liver mitochondrial and/or microsome fractions. However, proteasome activation was significantly attenuated when fractions were obtained from ethanol-fed animals.

Ex Output:
Is proteasome activation by hepatitis C core protein reversed by ethanol-induced oxidative stress?


Ex Input:
Vascular endothelial growth factor (VEGF) has been well documented to stimulate cell proliferation and differentiation; however, we have observed that copper (Cu)-induced regression of heart hypertrophy was VEGF-dependent. The present study was undertaken to test the hypothesis that Cu causes alterations in the distribution of VEGF receptors (VEGFRs) in hypertrophic cardiomyocytes so that it switches the signalling pathway from stimulation of cell growth to reversal of cell hypertrophy.', 'Primary cultures of neonatal rat cardiomyocytes were exposed to phenylephrine (PE) at a final concentration of 100 microM in cultures for 48 h to induce cell hypertrophy. The hypertrophic cardiomyocytes were exposed to copper sulfate at a final concentration of 5 microM in cultures for 24 h with a concomitant presence of PE. Flow cytometry, gene silencing, and ELISA procedures were used to analyse the changes in VEGFRs and their relationship with regression of cardiomyocyte hypertrophy. Cu did not change the concentration of VEGF in culture media, but increased the ratio of VEGFR-1 to VEGFR-2 two-fold. Gene silencing of VEGFR-2, in the absence of Cu addition, reversed PE-induced cardiomyocyte hypertrophy, which was suppressed by an anti-VEGF antibody. Gene silencing of VEGFR-1 blocked Cu-induced regression of cell hypertrophy and decreased the activity of cGMP-dependent protein kinase-1 (PKG-1). A PKG-1 antagonist, Rp-8-pCPT-cGMPS, blocked both Cu- and VEGFR-2 gene silencing-induced regression of cardiomyocyte hypertrophy.

Ex Output:
Is copper-induced regression of cardiomyocyte hypertrophy associated with enhanced vascular endothelial growth factor receptor-1 signalling pathway?


Ex Input:
It remains unclear which gene induction effectively generates photoreceptor-specific phenotypes from nonretinal tissues. The purpose of this study was to determine whether Crx and Otx2--homeobox genes related to photoreceptor development--can induce the generation of these phenotypes in cells derived from adult ciliary and iris tissue and in mesencephalon-derived neural stem cells.', 'Crx and Otx2 were transferred into adult rat ciliary- and embryonic mesencephalon-derived neurospheres and adult rat iris-derived cells with the aid of a recombinant retrovirus. The presence of photoreceptor-specific phenotypes was confirmed by immunocytochemistry and Western blot analysis.', 'More than 90% of the Crx- and Otx2-transfected ciliary- and iris-derived cells exhibited rod opsin immunoreactivity, whereas few of the similarly transfected mesencephalon-derived neural stem cells expressed rod opsin. At least two additional key components of the phototransduction cascade, recoverin and Gdeltat1, were expressed by Crx- and Otx2-transfected iris-derived cells.

Ex Output:

Does otx2 homeobox gene induce photoreceptor-specific phenotypes in cells derived from adult iris and ciliary tissue?