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CASE STUDY | Zigs and zags of the smallpox virus
Smallpox, a once highly lethal contagious disease, has been eradicated worldwide. However, research continues with stored samples of variola, the smallpox virus, because it is a potential weapon in bioterrorism. Human cells protect themselves from the variola virus (and other viruses) by activating genes that encode protective proteins. It has recently been discovered that in response to variola, human cells create small transitory stretches of Z-DNA at sites that regulate these genes. The smallpox virus can bypass this cellular defense mechanism by specifically targeting the segments of Z-DNA and inhibiting the synthesis of the protective proteins. This discovery raises some interesting questions:
How might the virus target host-cell Z-DNA formation to block the synthesis of antiviral proteins?
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Essentials of Genetics (9th Edition) - Standalone book
- Several vaccines against viral infections are made by isolating purified surface proteins of the viral particle, mixing them with an adjuvant to stimulate an innate immune response, and injecting the mixture into people. Two examples of this are the vaccine against Hepatitis B virus, and the vaccine against Human Papilloma Virus (the ‘cervical cancer’ vaccine). One interesting property of vaccines of this type (known as ‘subunit vaccines’) is that there is a requirement for a CD4 T cell response to the vaccine antigen in order to generate antibodies to the innocuous protein in the vaccine. In the case of the Hepatitis B vaccine, the viral protein included in the vaccine is the Hepatitis B surface antigen (HepB-SAg), a protein that is approximately 200 amino acids in length. The graph in Figure Q4.27 shows the data from immunizing individuals with this vaccine, and monitoring their production of protective antibody responses to the viral protein. a) What results would be predicted if…arrow_forwardThe Adaptive Immune Response Is a Specific Defense Against Infection In cystic fibrosis gene therapy, scientists propose the use of viral vectors to deliver normal genes to cells in the lungs. What immunological risks are involved in this procedure?arrow_forwardHersheyChase Experiments The graph shown in FIGURE 8.5 is reproduced from an original 1952 publication by Hershey and Chase. Bacteriophage were labeled with radioactive tracers and allowed 10 infect bacteria. The virusbacteria mixtures were then whirled in a blender to dislodge any viral components attached to the exterior of the bacteria. Afterward, radioactivity from the tracers was measured. FIGURE 8.5 Detail of Alfred Hershey and Martha Chases 1952 publication describing their experiments with bacteriophage. Infected bacteria refers to the percentage of bacteria that survived the blender. How did the researchers know that the radioisotopes in the fluid came from outside of the bacterial cells and not from bacteria that had been broken apart by whirling in the blender?arrow_forward
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