You have identified an enhancer that drives Pax6 expression in the developing lens and cornea of the mouse eye. To identify regions of the enhancer that bind lens specific transcription factors (transcription factors expressed only in the lens but not the cornea) you perform a linker scanning experiment in which you mutate 10 bp regions centered around positions 5 to 95 bp of the enhancer. The enhancer variants are tested for their ability to activate expression of Pax6 in both the cornea and lens of the developing mouse. You isolate each tissue separately and carry out a northern blot for Pax6 mRNA on each sample as shown below. List which lane A-J of the northern blot contains a region of the enhancer that binds a lens-specific transcription factor. Explain how you determined this referencing specific data from the gel and your knowledge of the molecular biology involved in regulating transcription. A B C D E F G H I J 5 15 25 35 45 55 65 75 85 95 WT Cornea Lens Northern Blot for Pax6 mRNA

You have identified an enhancer that drives Pax6 expression in the developing lens and cornea of the mouse eye. To identify regions of the enhancer that bind lens specific transcription factors (transcription factors expressed only in the lens but not the cornea) you perform a linker scanning experiment in which you mutate 10 bp regions centered around positions 5 to 95 bp of the enhancer. The enhancer variants are tested for their ability to activate expression of Pax6 in both the cornea and lens of the developing mouse. You isolate each tissue separately and carry out a northern blot for Pax6 mRNA on each sample as shown below. List which lane A-J of the northern blot contains a region of the enhancer that binds a lens-specific transcription factor. Explain how you determined this referencing specific data from the gel and your knowledge of the molecular biology involved in regulating transcription. A B C D E F G H I J 5 15 25 35 45 55 65 75 85 95 WT Cornea Lens Northern Blot for Pax6 mRNA

Human Anatomy & Physiology (11th Edition)

11th Edition

ISBN:9780134580999

Author:Elaine N. Marieb, Katja N. Hoehn

Publisher:Elaine N. Marieb, Katja N. Hoehn

Chapter1: The Human Body: An Orientation

Section: Chapter Questions

Problem 1RQ: The correct sequence of levels forming the structural hierarchy is A. (a) organ, organ system,...

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Part A You were sequencing a region of 200 kb in Effrenium voratum (a member of the family Symbiodiniaceae) and you found two genes, an insulator, and two enhancers, as shown below. Gene A Promoter gene A Enhancer I Enhancer I| Insulator Promoter gene b Gene B Q: What would happen if you do some gene editing and you move the insulator between both enhancers? The newly positioned insulator allows enhancer II to activate gene B transcription The newly positioned insulator allows enhancer I to hyperactivate gene B transcription The new positioning of the insulator prevents gene A expression It will be unaltered The newly positioned insulator prevents enhancer II from stimulating the transcription of gene B
Match whether the protein binds directly or indirectly (assuming it does) to DNA and whether to the enhancer or promoter. Items may be matched to multiple choices and not all choices will be used. 1. Directly to enhancer Repressors 2. Directly to promoter Activators 3. Indirectly to enhancer TBP associated factors 4. Indirectly to promoter >
The APETALA1:GUS line you were given is a transcriptional fusion. Given that APETALA1 encodes a transcription factor, where might you expect to detect the expression of a translational reporter gene fusion?
After further investigation, you discovered that HHT1 and HHT2 are produced via alternative splicing. HHT1 is expressed in the liver, and HHT2 is expressed in the pancreas. Regarding the regulation of their expression, you conclude: all answers are possible the regulation occurs at the epigenetic level the regulation occurs at the transcriptional level the regulation occurs at the level of splicing
A. Based on this data, draw a conclusion about the promoter elements that Caudal specifically upregulates. B. Dr. Juven-Gershon also tested Caudal activation of core promoter sequences from twoother genes. Similar to the first experiment, one was DPE-dependent (from the E74Bgene), and the other was TATA-dependent (from the Adh gene). However, these two corepromoters lacked the BREU motif. The results from these additional core promoters areshown below. Based on these results and those shown above, propose a hypothesis thatexplains the differences in Caudal-mediated upregulation among all the different corepromoters Dr. Juven-Gershon tested. C. To test your hypothesis from Question 3B, you plan perform the same method of genereporter assays that Dr. Juven-Gershon has done. However, you will need to do somemutations to alter the core promoters. Make diagrams or clearly describe all the variouscore promoters mutants you wish to test. These include your controls, as well as any…
IIVY is a LysR regulator, and it helps control transcription of a neighboring gene, ilvC. IlvY can either bend the DNA and block RNAP's access to ilvC's -35 promoter site, or it can allow access to the ilvC -35 site, thereby promoting ilvC transcription. What determines whether llvY is repressing or activating transcription from the ilvC promoter? The presence of the co-inducer acetolactate - acetolactate binds to llvY and changes llvY's shape such that it doesn't block the -35 of the ilvC promoter. IlvY represses ilvC transcription when the IlvC protein is bound to llvY, and it activates ilvC transcription when the lvC protein is not present to bind to llvY. The presence of the co-inducer valine - when valine is present, it binds llvY and causes llvY to repress transcription from the ilvC promoter. The presence of the co-inducer acetolactate - acetolactate induces negative supercoiling at the ilvC promoter, which represses ilvC transcription.
Using bacteria that express double stranded RNA upon induction by IPTG, investigators have constructed an RNAi library that allows you to feed C. elegans bacteria that expresses dsRNA corresponding to a given gene to obtain progeny that have been compromised for this target mRNA. This was performed for every predicted gene in the animal. From this experiment, 1200 genes of the 19000 predicted genes tested caused sterility in adult animals. 200 of the 1200 candidates that cased sterility were of unknown function. Q4a) What can we conclude from this information? Q4b) What processes are the genes with unknown function likely involved in?
You identify a fragment of DNA that, when fused to a GFP reporter, can express GFP in a mouse's eyes. You suspect some piece of that fragment represents a promoter and another piece represents an enhancer. You want to know which is which. What experiments do you perform to see which piece is a promoter and which is an enhancer? Hint: remember the important differences between promoters and enhancers. Then build constructs that test those differences.