Given a passage with a context and an answer, 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:
Context: Pandemic strains of HIV-1 (group M) encode a total of nine structural (gag, pol, env), regulatory (rev, tat) and accessory (vif, vpr, vpu, nef) genes. However, some subtype A and C viruses exhibit an unusual gene arrangement in which the first exon of rev (rev1) and the vpu gene are placed in the same open reading frame. Although this rev1-vpu gene fusion is present in a considerable fraction of HIV-1 strains, its functional significance is unknown.', 'Examining infectious molecular clones (IMCs) of HIV-1 that encode the rev1-vpu polymorphism, we show that a fusion protein is expressed in infected cells. Due to the splicing pattern of viral mRNA, however, these same IMCs also express a regular Vpu protein, which is produced at much higher levels. To investigate the function of the fusion gene, we characterized isogenic IMC pairs differing only in their ability to express a Rev1-Vpu protein. Analysis in transfected HEK293T and infected CD4+ T cells showed that all of these viruses were equally active in known Vpu functions, such as down-modulation of CD4 or counteraction of tetherin. Furthermore, the polymorphism did not affect Vpu-mediated inhibition of NF-B activation or Rev-dependent nuclear export of incompletely spliced viral mRNAs. There was also no evidence for enhanced replication of Rev1-Vpu expressing viruses in primary PBMCs or ex vivo infected human lymphoid tissues. Finally, the frequency of HIV-1 quasispecies members that encoded a rev1-vpu fusion gene did not change in HIV-1 infected individuals over time.
Answer: Expression of a rev1-vpu fusion gene does not affect regular Rev and Vpu functions or alter HIV-1 replication in primary target cells. Since there is no evidence for increased replication fitness of rev1-vpu encoding viruses, this polymorphism likely emerged in the context of other mutations within and/or outside the rev1-vpu intergenic region, and may have a neutral phenotype.

Ex Output:
Does a Naturally Occurring rev1-vpu Fusion Gene Confer a Fitness Advantage to HIV-1?

Ex Input:
Context: To describe the prevalence and correlates of hazardous drinking among female sex workers (FSWs) at 13 sites throughout Mexico.', 'FSWs (N = 1089) who were enrolled in a brief sexual risk reduction intervention (Mujer Segura) were queried about their sexual risk and substance use practices and their work contexts. Participants were classified as hazardous or non-hazardous drinkers based on the Alcohol Use Disorders test (AUDIT-C). Logistic regression models were used to examine individual, contextual, and community-level factors as correlates of hazardous drinking.', 'Ninety-two percent of participants reported alcohol consumption in the past month. Among drinkers (N = 1001), 83% met AUDIT-C criteria for hazardous drinking. Factors that were independently associated with hazardous drinking included: drug use in the past month (adjusted odds ratio (AOR) = 3.31; 95% CI 1.29-8.45), being a cigarette smoker (AOR = 1.71; 95% CI 1.13-2.58), being a barmaid or dance hostess (AOR = 3.40; 95% CI 1.95-5.91), alcohol use before or during sex with clients (AOR = 7.78; 95% CI 4.84-12.52), and working in a city with a higher marginalization index (AOR = 1.07; 95% CI 1.04-1.11).
Answer: Findings support the high prioritization by public health authorities of alcohol prevention and treatment programs for FSWs.

Ex Output:
Does prevalence and correlate of Hazardous Drinking among Female Sex Workers in 13 Mexican Cities?

Ex Input:
Context: For high-resolution microscopy, cells have to be analyzed through thin glass coverslips. Therefore, it is necessary to culture cells on coverslips for preservation of cell morphology. We found cell attachment and spreading to be relatively slow processes, even when cells were plated on coated coverslips. This slowness presents a problem, particularly when synchronized cell populations are used.', 'In this paper, we present a method that is based on glow-discharged carbon coating of coverslips which promotes rapid attachment and spreading of cells, enabling rapid analysis of cells after plating. Results obtained with carbon-coated coverslips were compared with those of other types of coating. Two fibroblast lines, an epithelial cell line, and a carcinoma cell line were tested.
Answer: All cell lines showed a rapid adhesion on carbon-coated coverslips. With fibroblasts we found the carbon coating to be superior to other coatings tested, mainly because the carbon did not influence cell morphology. Using synchronized or irradiated cells produced similar results. The superior performance of carbon coating is probably due to carboxylic groups on the glow-discharged carbon layer. The carbon layer does not interfere with microscopy or immunocytochemical staining procedures.

Ex Output:
Does coating of coverslips with glow-discharged carbon promote cell attachment and spreading probably due to carboxylic groups?