Method DNAS sensitivity to DNase I was tested on different tissues and at different times in development. Key DNA highly sensitive to DNase I Embryonic globin gene globin genes Adult Chicken DNA U aD Results Erythroblasts first 24 hours Before hemoglobin synthesis, none of the globin genes are sensitive to DNase I digestion. a4 After globin synthesis has begun, all genes are sensitive to DNase I, but the embryonic globin gene Uis the most sensitive. Erythroblasts 5 days In the 14-day-old embryo, when only adult hemoglobin is expressed, adult genes are most sensitive and the embryonic gene is insensitive. Erythroblasts 14 days Globin genes in the brain- which does not produce globin-remain insensitive throughout development. Brain cells throughout development Conclusion: Sensitivity of DNA to digestion by DNase I is correlated with gene expression, suggesting that chromatin structure changes in the course of transcription. DNase I sensitivity is correlated with the transcription of globin genes in chick embryos.

Method DNAS sensitivity to DNase I was tested on different tissues and at different times in development. Key DNA highly sensitive to DNase I Embryonic globin gene globin genes Adult Chicken DNA U aD Results Erythroblasts first 24 hours Before hemoglobin synthesis, none of the globin genes are sensitive to DNase I digestion. a4 After globin synthesis has begun, all genes are sensitive to DNase I, but the embryonic globin gene Uis the most sensitive. Erythroblasts 5 days In the 14-day-old embryo, when only adult hemoglobin is expressed, adult genes are most sensitive and the embryonic gene is insensitive. Erythroblasts 14 days Globin genes in the brain- which does not produce globin-remain insensitive throughout development. Brain cells throughout development Conclusion: Sensitivity of DNA to digestion by DNase I is correlated with gene expression, suggesting that chromatin structure changes in the course of transcription. DNase I sensitivity is correlated with the transcription of globin genes in chick embryos.

Biochemistry

6th Edition

ISBN:9781305577206

Author:Reginald H. Garrett, Charles M. Grisham

Publisher:Reginald H. Garrett, Charles M. Grisham

Chapter30: Protein Synthesis

Section: Chapter Questions

Problem 1P

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Mutations in the dnaA gene of E. coli are lethal and canonly be studied following the isolation of conditional,temperature-sensitive mutations. Such mutant strains grownicely and replicate their DNA at the permissive temperatureof 18°C, but they do not grow or replicate their DNA at therestrictive temperature of 37°C. Two observations were usefulin determiningthe function of the DnaA protein product.First, in vitro studies using DNA templates that haveunwound do not require the DnaA protein. Second, if intactcells are grown at 18°C and are then shifted to 37°C, DNAsynthesis continues at this temperature until one roundof replication is completed and then stops. What do theseobservationssuggest about the role of the dnaA gene product?
A sample of liver cells was collected froma healthy donor and from an individual with liver cancer.mRNA was isolated from both samples of cells and subjectedto DNA microarray analysis. In the results from the two samples,77 spots on the microarry from the cancer cells weremuch brighter compared to those for the cells from the healthydonor. How would you interpret these results? Explain theirmeaning with regard to the growth of the cancer cells. (Note:Assume that each spot corresponds to a different gene.)
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Utilizing Hind III and EcoR V Restriction Enzyme with Pet41 and the following gene of interest... a tgaaacaaca aaaacggctt tacgcccgat tgctgacgct gttatttgcg 61 ctcatcttct tgctgcctca ttctgcagca gcggcggcaa atcttaatgg gacgctgatg 121 cagtattttg aatggtacat gcccaatgac ggccaacatt ggaagcgttt gcaaaacgac 181 tcggcatatt tggctgaaca cggtattact gccgtctgga ttcccccggc atataaggga 241 acgagccaag cggatgtggg ctacggtgct tacgaccttt atgatttagg ggagtttcat 301 caaaaaggga cggttcggac aaagtacggc acaaaaggag agctgcaatc tgcgatcaaa 361 agtcttcatt cccgcgacat taacgtttac ggggatgtgg tcatcaacca caaaggcggc 421 gctgatgcga ccgaagatgt aaccgcggtt gaagtcgatc ccgctgaccg caaccgcgta 481 atttcaggag aacacctaat taaagcctgg acacattttc attttccggg gcgcggcagc 541 acatacagcg attttaaatg gcattggtac cattttgacg gaaccgattg ggacgagtcc 601 cgaaagctga accgcatcta taagtttcaa ggaaaggctt gggattggga agtttccaat 661 gaaaacggca actatgatta tttgatgtat gccgacatcg attatgacca tcctgatgtc 721 gcagcagaaa ttaagagatg gggcacttgg tatgccaatg aactgcaatt ggacggtttc 781…
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A sample of liver cells was collected from a healthy donor and from an individual with liver cancer. mRNA was isolated from both samples of cells and subjected to DNA microarray analysis. In the results from the two samples, 77 spots on the microarray from the cancer cells were much brightercompared to those for the cells from the healthy donor. How wouldyou interpret these results? Explain their meaning with regard to thegrowth of the cancer cells. (Note: Assume that each spot correspondsto a different gene.)
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