1)Tamoxifen is used as a drug to treat breast cancers. When effective, tamoxifen
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Question
1)Tamoxifen is used as a drug to treat breast cancers. When effective, tamoxifen slows tumor growth and prevents the reoccurrence of the cancer. However, some breast cancers are resistant to tamoxifen and continue to spread even if the patient takes high doses of the drug. The nuclear proteins of tumors that are resistant to tamoxifen were analyzed. It was discovered that resistant tumors often have decreased levels of the co-repressor, Nu-CoR. Explain how this reduction in Nu-CoR may explain why these tumors are resistant to tamoxifen treatment.
2) The estrogen receptor recruits CBP to estrogen responsive genes. CBP has HAT activity which acetylates histone tails near the ERE. Describe two mechanisms by which histone acetylation results in higher levels of expression of estrogen responsive genes.
3) In the yeast the gal80 gene regulates expression of the gal1 gene. Many mutations in gal80 result in constitutive expression of gal1(gal 1 expressed in the presence or absence of galactose). However there are rare mutations in gal80 that result in non-inducible gal1 expression (gal 1not expressed either in the presence or absence of galactose). At the molecular level, explain how the rare allele of gal80 results in the gal1 gene always being “off”.
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1)Tamoxifen is used as a drug to treat breast cancers. When effective, tamoxifen
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