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Eukaryotic Gene Expression Regulation

Eukaryotic Gene Expression Regulation. Why are eukaryotes capable of regulating gene expression at multiple points?. Why is it essential that the cells of multicellular eukaryotes have a complex and tightly controlled regulatory system?. DIFFERENTIATION of Individual cells!

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Eukaryotic Gene Expression Regulation

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  1. Eukaryotic Gene Expression Regulation

  2. Why are eukaryotes capable of regulating gene expression at multiple points?

  3. Why is it essential that the cells of multicellular eukaryotes have a complex and tightly controlled regulatory system? • DIFFERENTIATION of Individual cells! • Specialized cells must maintain a specific program of gene regulation

  4. DNA Packing: Only Keep necessary genes accessible • Extensive coiling and folding • Histones: small proteins that associate with DNAto form Nucleosomes • Continued folding “supercoil” • This system can block transcription by preventing RNA polymerase to bind

  5. What is the purpose of adding methyl groups to DNA? • Marks regions with low or no transcriptional activity (Heterochromatin)

  6. Pre-Transcription • Regulatory Genes – Produce regulatory proteins (activators and repressors) • DNA sequences that can activate (enhancers) or inhibit (silencers) transcription

  7. What are transcription factors? • Any proteins that Mediate the transcription Process • T.F.s bind to specific DNA sequences and/or Other regulatory proteins • Can be activators or repressors

  8. What are transcription factors? • The combination of T.F.s binding to the Regulatory regions at any One time determines how Much, if any, of the gene Product will be produced • RNA polymerase cannot Bind without T.F.s present

  9. Why is it important that cells of multicellular organisms be able to control the availability of transcription factors in cells? • This enables cells of multicellular organisms to accomplish “differential gene expression” • This enables cells to differentiate! • This is CRUCIAL!!!

  10. Post-Transcription: Alternative Splicing

  11. Pre-Translation: micro RNAs • MiRNAs are produced After the transcript for them Is cleaved into multiple Fragments by a dicer protein • miRNAs complex with protein • Any mRNA with a Complementary sequence is “tagged with the miRNA/protein Complex • mRNA is not translated

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