The gain-of-function ANTP mutant in Drosophila has legs growing in the place of antennae. What is the most appropriate inference about the function of the wild-type (normal) ANTP gene from this observation alone? ANTP is normally transcribed in antennae cells ANTP is necessary for leg development None of the options are correct ANTP is necessary for antennae development ANTP encodes a regulatory transcription factor

The gain-of-function ANTP mutant in Drosophila has legs growing in the place of antennae. What is the most appropriate inference about the function of the wild-type (normal) ANTP gene from this observation alone? ANTP is normally transcribed in antennae cells ANTP is necessary for leg development None of the options are correct ANTP is necessary for antennae development ANTP encodes a regulatory transcription factor

Concepts of Biology

1st Edition

ISBN:9781938168116

Author:Samantha Fowler, Rebecca Roush, James Wise

Publisher:Samantha Fowler, Rebecca Roush, James Wise

Chapter9: Molecular Biology

Section: Chapter Questions

Problem 10RQ: Control of gene expression in eukaryotic cells occurs at which level(s)? a. only the transcriptional...

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Many genes whose expression is turned on by DNAdamage have been isolated. Loss-of-function mutations in the lexA gene lead to the expression of manyof these genes, even when there has been no DNAdamage. Would you hypothesize that LexA protein isa positive or a negative regulator? Why?
In flies, the gap gene kruppel is expressed in a broad band in the middle of the embryo with giant expressed as its anterior border and knirps at its posterior border. How is the expression of kruppel limited to this band in the embryo? Describe the spatial regulation of the kruppel gene.
MyoD is a transcriptional activator that turns on theexpression of several muscle-specific genes in humancells. The Id gene product inhibits MyoD action.a. One possibility is that the Id protein directly represses the expression of these muscle-specificgenes. Explain how Id would function if it were arepressor.b. Another possibility is that Id inhibits musclespecific gene transcription indirectly, by preventingMyoD function. Explain how Id could function asan indirect repressor.c. Suppose you know the amino acid sequence ofthe Id protein. How might this information supportthe hypothesis in part (a) or in part (b)?
Pax6 is a gene that is involved in mammalian eye development. Mutations in this gene result in a lack of iris in humans, and mice that are homozygous for the mutation lack eyes completely. Mutations in the eyeless gene in the fruitfly Drosophila result in reduced eyes. Expressing Pax6 from mammals in other tissues of Drosophila during its embryonic development can result in an ectopic eye (e.g. an eye expressed in a different tissue type). An example of an ectopic eye on the antenna of Drosophila is shown below. Part A: The eye of humans, mouse, and fly are an example of the following (check all that apply) A. Structural analog B. Structural homolog C. Developmental homolog D. Genetic homolog Part B: Darwin's hypothesis of natural selection has two components: Species are not static but change through time Species are related, and not independent. In what ways does the human, mouse, and fly eye support or contradict one or both of the two components of…
Homeotic genes(A) encode transcription factors that control the expression ofgenes responsible for specific anatomical structures.(B) are found only in Drosophila and other arthropods.(C) are the only genes that contain the homeobox domain.(D) encode proteins that form anatomical structures in the fly.
The extracellular protein factor Decapentaplegic(Dpp) is critical for proper wing development in Drosoph-ila (Figure Q21–3A). It is normally expressed in a narrowstripe in the middle of the wing, along the anterior–pos-terior boundary. Flies that are defective for Dpp formstunted “wings” (Figure Q21–3B). If an additional copyof the gene is placed under control of a promoter that isactive in the anterior part of the wing, or in the posterior part of the wing, a large mass of wing tissue composed ofnormal-looking cells is produced at the site of Dpp expres-sion (Figure Q21–3C and D). Does Dpp stimulate cell divi-sion, cell growth, or both? How can you tell?
Suppose you want to determine whether a particulargene X is important for specification of the pharynx,but mutations in this same gene disrupt embryonicdevelopment well before pharyngeal structures appear.How could you use myo-2::GFP, the myo-2 promoter,the DNA sequence of gene X, and your knowledge ofRNA interference (RNAi) to generate worms that lackgene X expression in the pharynx but express gene Xin all other tissues in which it is expressed in wildtype C. elegans?
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In flies developing from eggs laid by a nanos−mother, development of the abdomen is inhibited.Flies developing from eggs that have no maternallysupplied hunchback mRNA are normal. Flies developing from eggs laid by a nanos− mother that alsohave no maternally supplied hunchback mRNA arenormal. If too much Hunchback protein accumulatesin the posterior of the egg, abdominal developmentis prevented.a. What do these findings say about the function ofthe Nanos protein and of the hunchback maternallysupplied mRNA?b. What do these findings say about the efficiency ofbiological processes that are subject to evolution?
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The TBX20 transcription factor is important for the developmentof heart tissue. Deletion of the Tbx20 gene in mice results in poorheart development and the death of mice well before birth. Tobetter understand how TBX20 regulates heart development ata genetic level, Sakabe et al. (2012. Hum. Mol. Genet. 21:2194–2204) performed a transcriptome analysis in which they comparedthe levels of all mRNAs between heart cells from wild-typemice and mice with Tbx20 deleted. This study concluded that TBX20 acts as an activator ofsome genes but a repressor of other genes in cardiac tissue.How might a single transcription factor have oppositeeffects on the transcription of different genes?