Each year in the United States, there are over 230,000 new cases of prostate cancer and almost 28,000 deaths. A 3.8-Mb region on chromosome 8 (8q24), called a gene desert, has very few genes but contains enhancer sequences that potentially confer significant risks for prostate cancer. One particular enhancer allele, which is kncwn to be associated with an elevated risk for prostate cancer, physically interacts with the promoter region of the nearby MYC gene and facilitates its upregulation. Overexpression of MYC, which encodes a cell-cycle regulatory protein, is observed in multiple types of cancer (see Chapter 24). The risk allele has a frequency of 49 percent in men of European descent and 81 percent in men of African ancestry. Most of the differential MYC activity associated with the risk allele occurs during prenatal development, raising the possibility that testing for this allele early in life can be used to identify those in the African-American population who are at very high risk for prostate cancer. However, researchers cannot rule out the possibility that this enhancer causes overexpression of other genes, which may also be involved in prostate cancer.
How do enhancers control the expression of genes located some distance away from the enhancer?
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EBK CONCEPTS OF GENETICS
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- In a mutant mouse, it was discovered that a gene "W" is moved from its original chromosomal locus to the telomere region, where chromatin is packed into heterochromatin. Given what we have learned about eukaryotic gene regulation, can you speculate how the expression of gene W in the new mouse line would be changed as compare to the normal mouse? elevated in the mutant mouse than in the wild-type mouse. cannot be determined. O reduced in the mutant mouse than in the wild-type mouse. change in the mutant mouse as compared to the wild-type mouse.arrow_forwardWhen the organization of adjacent genes with highly similar sequences is in an inverted orientation, this can reduce the expression of other genes that have similar sequence and are located on other chromosomes. Explain the mechanism of how this generally occurs.arrow_forwardIn humans, the average length of a gene on chromosome 7 is 69,000 base pairs, but the average MRNA length on chromosome 7 is only 2,500 base pairs. Chromosome 7 has 863 protein-coding genes, but many more than 863 proteins are made from the genes on chromosome 7. The observation that the length of the average gene on chromosome 7 is longer than the average mRNA length is explained by the process of while the observation that more proteins are produced from the genes on chromosome 7 than there are genes can be explained by the process of O heterogeneity; complementation splicing of introns; alternative splicing O chromatin remodeling; micro RNA binding acetylation; methylation alternative splicing; splicing of intronsarrow_forward
- Flowering Locus C (FLC) is a gene that is responsible for flowering in certain plants. FLC is normally expressed in new seedlings, which prevents flowering. When a plant is exposed to cold temperatures, FLC expression decreases and the plant produces flowers. FLC is regulated through epigenetic modifications. Based on this information, you should expect which of the following in histone proteins near the FLC gene: 1.In new seedlings, histones will be acetylated; while in the cold, histone methylation occurs 2.In new seedlings, histones will be methylated; while in the cold, histone acetylation occurs 3.In new seedlings, histones will be methylated; while in the cold, histone deacetylation occursarrow_forwardA gene, which we will call gene C, can be epigenetically modified in such a way that its expression in some cells is permanently silenced. Describe how you could conduct cell-fusion experiments to determine if a cis- or a trans-epigenetic mechanism is responsible for maintaining the silencing of gene C.arrow_forwardIn the Fast Forward Box Visualizing X Chromosome Inactivation in Transgenic Mice, suppose the investigators had looked at the expression of green and red fluorescent protein in early mouse embryos, when the embryos have fewer than 500 cells. What patterns would they likely have observed?arrow_forward
- Geneticists often use ethylmethane sulfonate (EMS) to induce mutations in Drosophila. Why is EMS a mutagen of choice for genetic research? What would be the effects of EMS in a strain of Drosophila lacking functional mismatch repair systems?arrow_forwardIn a mutant mouse, it was discovered that a gene "W" is moved from its original chromosomal locus to the telomere region, where chromatin is packed into heterochromatin. Given what we have learned about eukaryotic gene regulation, can you speculate how the expression of gene W in the new mouse line would be changed as compare to the normal mouse? Question 18 options: elevated in the mutant mouse than in the wild-type mouse. cannot be determined. reduced in the mutant mouse than in the wild-type mouse. no change in the mutant mouse as compared to the wild-type mouse.arrow_forwardIn a qPCR experiment, you find that the mRNA for the gene CDK1 goes down (decreased expression) when you treat your cells with doxorubicin. You wonder whether this is due to epigenetic changes on the gene for CDK1. Name two methods that you might use to check whether there are changes in epigenetic modifications (e.g. DNA methylation or histone tail modifications) on the CDK1 DNA.arrow_forward
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