Regulation of Gene Expression

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Lecture 16

• Regulation of Gene Expression

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Gene expression the process by which a
genes DNA sequence is converted into a gene
product protein (mRNA), tRNA, or rRNA
Each step in the process of gene expression
can be regulated
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DNA is packed into chromatin
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Step1 Modifying the chromatin structure histone
acetylation or methylation
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Step 2 Regulation of Transcription
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Promoter/Enhancer function depends on
available transcription factors different cells
have different transcription factors available
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Step 3 Post-transcriptional Regulation
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Step 4 Regulating mRNA stability and Step 5
Regulating Initiation of Translation
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Step 6 Regulating Protein Stability
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Genetic changes that make things go awry..
proto-oncogene a normal gene that can become an
oncogene
oncogene a modified gene that encodes for a
protein that can increase the chance that
a normal cell can become a tumor cell or convert
a tumor cell to a malignant cell
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ras GTP-binding protein -part of the
MAPK pathway (signal transduction) -this pathway
induces cell division
p53 DNA binding protein -holds a cell at the
G1/S or G2/M boundary -induces DNA
repair machinery
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