All of the homeotic genes in Drosophila have been cloned. As discussed in Chapter 21, cloned genes can be manipulated in vitro. They can be subjected to cutting and pasting, gene mutagenesis, etc. After Drosophila genes have been altered in vitro, they can be inserted into a transposon vector (i.e., a P element vector), which can be injected into Drosophila embryos. The P element then transposes into the chromosomes, thereby introducing one or more copies of the altered gene into the Drosophila genome. This method is termed P element transformation.
With these ideas in mind, how would you create a gain-of-function mutation that caused the Antp gene to be expressed where the abd-A gene is normally expressed? What
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Genetics: Analysis and Principles
- Expression of recombinant proteins in yeast is an important tool for biotechnology companies that produce new drugs for human use. In an attempt to get a new gene X expressed in yeast, a researcher has integrated gene X into the yeast genome near a telomere. Will this strategy result in good expression of gene X? Why or why not? please try to explain a bit elaborately.arrow_forwardThe restriction digests of the cloned Drosophila gene can provide direct visible evidence of a mutation, as these samples come from a clone of the gene. In order to similarly detect a mutation in the copy of the endogenous gene within the Drosophila genome, a mechanism for specifically detecting restriction fragments from that gene among the complex set of fragments generated in a restriction digest of the entire Drosophila genome. Remember that the Drosophila melanogaster genome consists of ~123,000 kb. For a 10.2 kb Drosophila gene, what fraction of the genome does this gene constitute?arrow_forwardSuppose a researcher has three different Drosophila strains that have mutations in the bicoid gene called bicoid-A, bicoid-B, and bicoid-C; the wild type is designated bicoid +. To study these mutations, phenotypically normal female flies that are homozygous for the given bicoid mutation were obtained, and their oocytes were analyzed using a Northern blot to determine the size and/or amount of the bicoid mRNA and in situ hybridization to determine the bicoid mRNA location within the oocyte. A wild-type strain was also analyzed as a control. In both cases, the probe was complementary to the bicoid mRNA and the results are shown below. (Anterior is on the left; posterior is on the right.) Northern blot 1 2 - 3 4 In situ hybridization Wild type Lane 1. Wild type (bicoid*) Lane 2. bicoid-A Lane 3. bicoid-B Lane 4. bicoid-C bicoid-B bicoid-A bicoid-C Which mutation is likely to cause the embryo to develop two "anterior" ends? bicoid-B Obicoid-A bicoid-Carrow_forward
- expression of recombinant proteins in yeast is an important tool for biotechnology companies that produce new drugs for human use.in an attempt to get a new gene X expressed in yeast, a researcher has integrated gene X into the yeast genome near a telomere. will this strategy result in good expression of gene X? why or why not?arrow_forwardThe transcription factor Pax6 is required continually during the life of a mouse (or a human) for the development of the retina. Homozygous Pax6 knockout mice die soon after birth because Pax6 protein is also required in essential organs, such as the pancreas. a) In order to study the role of Pax6 in eye development a researcher wants to generate a mouse that expresses Pax6 everywhere except in its eyes. Describe how you could construct such a mouse by floxing the gene. Is it possible to achieve the same end with a transgene? (Hint: think about using cDNA and RNAI) b) Suppose you want to create a mouse similar to that in part (a), but one where the eye cells from Pax6 function has been removed and now express a gene that specifies a green fluorescent protein (GFP). Marking the cells in this way will allow the investigators to see the shapes of the Pax6- eye cells more easily than if they did not express GFP. Diagram a Pax6 gene construct that would enable the researcher to do this…arrow_forwardIn a particular organism, there are two similar genes called YFG1 and YFG2. YFG1 is expressed in the liver and not in the pancreas, and YFG2 is expressed in the pancreas but not the liver. Neither YFG1 nor YFG2 is expressed in the heart. If you extract DNA from heart cells, do you expect to see the YFG2 gene? Explain why. Do you expect to see the YFG1 protein when you analyze protein extract from liver cells? And from pancreas cells? And from heart cells? Explain why. Is it possible to produce YFG1 and YFG2 proteins via alternative splicing? Explain one possible way (mechanism) to regulate the expression of YFG1 gene.arrow_forward
- You have been analyzing wing development mutants in Drosophila and have collected the genetic/Western data below. Your epistasis analysis (not shown), suggested your current model that DW-2 is upstream of WL-1. What is a plausible mechanism for how DW-2 regulates WL-1? mutant name wingless-1 doublewing-2 Prated with Ants-Wingless MW standards || | | mutanttype ODW-2 inhibits transcription of WL-1 O DW-2 polyubiquitinates WL-1 null null phenotype Model Ac O DW-2 phosphorylates WL-1 and prevents it from entering the nucleus O DW-2 cleaves WL-1 proteolytically Wings Mode of regulation DW-2 Wings Wingsarrow_forwardAlthough several different mammalian species have been cloned, the efficiency of this process is extremely low. Often tens or even hundreds of oocytes must be implanted with donor nuclei to obtain one healthy live birth. Many researchers believe the difficulties with cloning reside in the epigenetic modifications, such as DNA and histone methylation, that occur within various cells during an individual’s life. How do you suspect such modifications might affect the success of an experimentarrow_forwardExplain one experimental strategy for determining the functional role of the mouse HoxD-3 gene.arrow_forward
- You are working with a fly hair cell developmental system. This Notch/Delta-regulated system results in clusters of cells where the central one differentiates into a specialized hair cell. To better understand this system you have tagged the C-terminal cytoplasmic domain of Notch with GFP. You have done a forward genetic screen to look for mutants that have unusual phenotypes in this Notch system. The first one is a mutation in Notch itself. This mutant is in the ADAM10 cleavage site and blocks proteolysis. Draw the expected outcome for such a mutant: GFP localization and developmental outcome 24hr after differentiation. WT before differentiation WT 24 hours after differentiationarrow_forwardA wild type strain of Drosophila was found to carry a transposable element called copia.From this strain (red eyed), a white-eyed strain was obtained in which the copia element hadtransposed to a region on the X-chromosome that corresponded to where the eye-color genemapped. How would you clone the eye-color gene and confirm your discovery?arrow_forwardIn the bacteriophage T7 system used to express recombinant proteins, the gene of interest is fused to T7 promoter and T7 RNA polymerase is separately cloned into the same cell. What is the main reason this system uses T7 RNA polymerase instead of relying on the bacterial RNA polymerase? To restrict the expression of bacterial protein expression To enhance the amount of recombinant protein expression To enhance the expression of bacterial protein expression To restrict the amount of recombinant protein expression To enable the expression of T7 viral protein expressionarrow_forward
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