development - MIT Department of Biology 7.02 Experimental...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
1 MIT Department of Biology Spring 2005 7.02/10.702 Development Exam Study Questions Please note: 1. While the exam given on May 19 th will not be “cumulative,” you should note that many of your interpretation questions and a number of these study questions (taken from old DEV exams) ask you to make connections between the DEV and other modules in the course. You should think about these connections as you prepare for the exam!
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Question 1 (x points) Your UROP project focuses on two genes, Par1 and Mst5, which you suspect are involved in the embryonic development of the mouse. To study these genes, you isolate total DNA, total RNA, and total protein samples from mice at the following developmental stages: 1) early embryos (8 days post fertilization, or 8dpf) 2) late embryos (15 days post fertilization, or 15dpf) 3) newborn pups (NB) 4) 3 month old adults (A) The expression of Par1 and Mst5 during development may be controlled at the RNA level (by regulating either transcription or mRNA stability) or at the protein level (by regulating translation or protein stability). To begin to understand Par1's regulation, you decide to perform Northern and Western blots on your samples. b) Compare and contrast the Northern and Western blot procedures by completing the following table: Northern blot Western blot What method(s) will you use to denature your samples? What type of gel will you run? In what direction will your samples migrate in the gel? What ensures this? What specific type of "probe" will you use to detect Par1 mRNA or protein?** **you may assume you use the same general type of "probe"—and the same reagents to "visualize" the probe—as you used in 7.02 lab.
Background image of page 2
3 Question 1 (continued) You perform the Western blot first, and probe the membrane for Par1 and another protein, tubulin. (Tubulin is a cytoskeletal protein expressed at constant levels throughout development and in the fully developed mouse.) You observe the following on your blot: 8dpf 15dpf newborn (NB) adult (A) <--Par1 protein <--Tubulin b) Why did you probe your membrane for tubulin as well as for Par1? c) Is Par1 protein expressed during embryonic development? (circle one) YES NO d) Is Par1 protein required in the adult mouse? (circle one) YES NO You next perform a Northern blot, probing for Par1. You develop the blot, expose it to film, and obtain the result shown below: NB A 9.5 7.5 4.4 2.4 1.4 8dpf 15dpf MW NB A MW 8dpf 15dpf 9.5 7.5 4.4 2.4 1.4 EtBr stained gel Film e) Your labmate concludes that Par1 is not transcribed in newborn mice. Do the gel and Northern blot data definitively support his conclusion? Why or why not?
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
4 Question 1 (continued) f) Based on the data from the Par1 Western and Northern blots, how is Par1 expression regulated in mice? (circle one) RNA level protein level g) Justify your answer to part f), referring to specific lanes of the blot/film that support your conclusion. To study Mst5 regulation, you first decide to perform a Northern blot. You re-extract total
Background image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 06/11/2008 for the course PSY 341 taught by Professor Driesen during the Spring '08 term at Portland State.

Page1 / 27

development - MIT Department of Biology 7.02 Experimental...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online