SQ5revised

SQ5revised - MCDB 112, F10 STUDY QUESTION SET 5 page 1...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
MCDB 112, F10 STUDY QUESTION SET 5 page 1 Study Question Set 5 – Covers Lecture Set #5 Material 1. In our discussion of Drosophila D-V axis specification, we talked about dorsal , a gene that is necessary for ventral structures to form. A LoF mutation in dorsal results in an embryo with no ventral structures – the embryo is “dorsalized.” In a wild type embryo, the Dorsal protein is present throughout the early embryo, but enters the nuclei only in the ventral side, where it eventually activates “ventral-specifying” genes and represses “dorsal-specifying” genes. Cactus is a protein that binds to Dorsal protein. Cactus is also present throughout the early embryo. 1A. Describe one possible scenario of how Cactus works to regulate Dorsal protein entry into nuclei. 1B. Based on your answer to 1A, what do you predict is the phenotype of a cactus LoF mutation? 1C. Describe one possible scenario of how asymmetry in Cactus function or activity is generated. 2. Interestingly, some mutant alleles of dorsal result in ventralized embryos. These are considered to be gain of function (GoF) mutations. The GoF dorsal protein can enter all nuclei. 2A. How could a mutation in DNA sequence result in this GoF phenotype? (There are many possible answers, just keep it simple and use your logic regarding structure- function ). 2B. Based on your answers to 1A and 2A, what do you predict is the phenotype of a double mutant that has a GoF mutation for both cactus and dorsal ? Explain. (There are many possible answers – I am looking for logic in terms of how the two proteins interact and how the GoF mutations affect this). 3. Suppose that your colleague has cloned a gene called Eyeball . The Eyeball transcript is found only in the cells that give rise to the retina and she hypothesizes that Eyeball (Eyb) is required for normal retina development. Your colleague has made a variety of “expression constructs” to help her study Eyeball function and she asks you to help her evaluate her experimental plan. Here are the reporter constructs (GFP = green fluorescent protein; CA = constitutively active): Eyb promoter GFP cDNA Eyb promoter Eyb cDNA GFP cDNA CA promoter Eyb cDNA 3A. Which construct(s) would you choose to “rescue” a null mutation in eyeball ? Explain. 3B. Which constructs(s) would you choose to lineage trace the retinal cells? Explain. 3C. Which construct(s) would you choose to carry out an Eyeball gain-of-function experiment? Explain. 3D. Which construct(s) would you choose to determine when the Eyeball protein was functional? Explain.
Background image of page 1

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

View Full DocumentRight Arrow Icon
MCDB 112, F10 STUDY QUESTION SET 5 page 2 4. In early Drosophila development, gradients of transcription factors dictate precise patterns of gene expression in later development, ultimately setting the pattern along the A-P axis. Many of these transcription factors have homologues in other animals, including vertebrates. However,
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 6

SQ5revised - MCDB 112, F10 STUDY QUESTION SET 5 page 1...

This preview shows document pages 1 - 3. Sign up to view the full document.

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