EBK GENETICS: FROM GENES TO GENOMES
6th Edition
ISBN: 9781260041255
Author: HARTWELL
Publisher: MCGRAW HILL BOOK COMPANY
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Textbook Question
Chapter 20, Problem 22P
Neurofibromatosis type 1 (NF1; also known as von Recklinghausen disease) is an inherited dominant disorder. The
a. | Is it likely that NF1 is a tumor-suppressor gene or an oncogene? | ||||||||||||||
b. | Are the NF1 neurofibromatosis-causing mutations that are inherited by affected children from affected parents likely to be loss-of-function or gain-of-function mutations? | ||||||||||||||
c. | Neurofibromin, the protein product of NF1, has been found to be associated with the Ras protein. Ras is involved in the transduction of extracellular signals from growth factors. The active form of Ras (the form initiating the signal transduction cascade causing proliferation) is complexed with GTP; the inactive form of Ras is complexed with GDP. Would the wild-type neurofibromin protein favor the formation of Ras–GTP or Ras–GDP? | ||||||||||||||
d. | Which of the following events in a normal cell from an individual inheriting a neurofibromatosis-causing allele could cause the descendants of that cell to grow into a neurofibroma?
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e. | A much rarer form of neurofibromatosis exists called segmental neurofibromatosis. In this form of the disease, neither parent of the patient has any clinical sign of the disease. The tumors in the patient are restricted to one part of the body, like the right leg. Suggest an explanation for the genesis of segmental neurofibromatosis that clarifies why it is restricted to one part of the body. |
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Chapter 20 Solutions
EBK GENETICS: FROM GENES TO GENOMES
Ch. 20 - For each of the terms in the left column, choose...Ch. 20 - Characterize the differences between tumor cells...Ch. 20 - Prob. 3PCh. 20 - Prob. 4PCh. 20 - A carcinogenic compound is placed on the skin of...Ch. 20 - You have decided to study genetic factors...Ch. 20 - B cells are specialized blood cells that secrete...Ch. 20 - Molecules outside and inside the cell regulate the...Ch. 20 - Put the following steps in the correct ordered...Ch. 20 - a. Would you expect a cell to continue or to stop...
Ch. 20 - Two different protein complexes called SCF and APC...Ch. 20 - One of the hallmarks of mitotic anaphase is the...Ch. 20 - Concerning the Tools of Genetics Box Analysis of...Ch. 20 - Are genome and karyotype instabilities...Ch. 20 - Prob. 15PCh. 20 - Why dont all loss-of-function mutations that are...Ch. 20 - Chromothripsis is a rare phenomenon, first...Ch. 20 - The chromosome 9/22 translocation associated with...Ch. 20 - A female patient 19 years old, whose symptoms are...Ch. 20 - Prob. 20PCh. 20 - A generic signaling cascade is shown in the...Ch. 20 - Neurofibromatosis type 1 NF1; also known as von...Ch. 20 - Families with germ-line BRCA1 or BRCA2...Ch. 20 - The text explained that retroviruses can cause...Ch. 20 - Hepatocellular carcinoma is the most frequent form...Ch. 20 - Suppose that instead of microarrays, you analyzed...Ch. 20 - Prob. 27PCh. 20 - Glioblastoma multiforme GBM is the most common and...Ch. 20 - a. The legend to Fig. 20.29 identifies which of...Ch. 20 - The website CBioPortal http://www.cbioportal.org...
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- Distinguish between proto-oncogenes and tumor-suppressor genes. To become cancer promoting, do proto-oncogenes and tumor-suppressor genes undergo gain-of-function or loss-of-function mutations? Classify the following genes as proto-oncogenes or tumor-suppressor genes: p53, ras, BCL-2, JUN, MDM2, and p16.arrow_forwardExplain why mutations in tumor suppressor genes are recessive (both copies of the gene must be defective for the regulation of cell division to be defective), whereas mutations in oncogenes are dominant.arrow_forwardAlthough slow acting retroviruses lack oncogenes, retroviral infection can activate proto oncogenes leading to oncogenesis. a. Describe the mechanism of proto-oncogenes activation that can result from with infection with slow acting retroviruses. b. In what other ways can proto-oncogenes be converted to oncogenes?arrow_forward
- Cancer-promoting mutations are likely to have different effects on the activity of proteins encoded byproto-oncogenes than they do on proteins encodedby tumor-suppressor genes. Explain.arrow_forwardWhat would be the effect of a mutation that inactivates the p14ARF tumor suppressor upon p53 functions?arrow_forwardThe p53 gene is a tumor-suppressor gene while Ras is a proto-oncogene. Mutation in either one can result in the transformation of a normal cell into a cancer cell. Explain the difference between the functions of the two proteins and how their mutation can lead to cancer development.arrow_forward
- How do BRCA1 and BRCA2 function in regard to cell proliferation (are they proto-oncogenes, oncogenes, or tumor suppressor genes)?arrow_forwardIn Metastatic Breast Cancer [such as in Breast Invasive Ductal Carcinoma; Breast Invasive Carcinoma, NOS; Breast Invasive Cancer, NOS; Invasive Breast Carcinoma; Breast Invasive Lobular Carcinoma; Breast Mixed Ductal and Lobular Carcinoma] what role does the genes Tp53 and Tp63 have? Would one of them affect the other (i.e. mutation, etc) or there is not relationship among the two genes at all.arrow_forwardIn tumor cells obtained from patients with Burkittlymphoma, a cancer of the immune system’s B cells,the myc gene often appears close to one of the breakpoints of a reciprocal translocation between chromosomes 8 and 14. In this translocated position, myc is expressed at a higher-than-normal level. Scientists hypothesize that Myc protein overexpression in B cellscontributes to lymphoma formation.a. Explain how transgenic mice produced using pronuclear injection could be used to test this hypothesis. (Assume that you previously cloned a generegulatory region that is active specifically in Bcells throughout the life of the mouse.)b. Suppose you wanted to overexpress Myc only inthe immune cells of mice, starting at one week ofage. To restrict Myc transcription spatially, youwill use same promoter described in part (a). Torestrict Myc transcription temporally, you will usea cre transgene whose expression is controlled byheat shock (hs-cre). Describe the mouse you wouldcreate to accomplish…arrow_forward
- Describe the common signal transduction event that is perturbed by cancer-promoting mutations in the genes encoding RAS and NF-1. Why are mutations in RAS more commonly found in cancers than mutations in NF-1?arrow_forward"In the cellular regulatory pathways that control cell growth and proliferation, the products of oncogenes are stimulatory components and the products of tumor suppressor genes are inhibitory components" is true or false.arrow_forwardDescribe the steps by which the TP53 gene responds to DNA damage and/or cellular stress to promote cell-cycle arrest and apoptosis. Given that TP53 is a recessive gene and is not located on the X chromosome, why would people who inherit just one mutant copy of a recessive tumor-suppressor gene be at higher risk of developing cancer than those without the recessive gene?arrow_forward
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