Eukaryotic gene regulation

Week 8:Eukaryotic Gene Regulation

Learning Goal: Understand mechanisms that help control gene expression in eukaryotes.

•Describe the role of histone proteins in DNA packaging, nucleosome formation, and chromatin structure.

Histone proteins are strings of AA and they play a role in DNA packaging as DNA is tightly wound around histones. Chromatin is what DNA is packaged in and it is a complex of DNA, RNA, and nucleosome proteins. Nucleosome proteins are multiple histones with DNA wrapped around them. In chromatin's native state, the DNA is not accessible. Nucleosomes are formed when chromatin is tightly coiled by DNA.  

•Discuss how histones are chemically modified to increase or decrease the expression of a gene.

When histones are acetylated they are decondensed which allows more things to bind and increases transcription. This process is referred to as nucleosome sliding and requires ATP because it loosens histones and frees the promoter. 

•Describe how DNA methylation affects gene expression in eukaryotes.

Prevents gene expression and transcription because the promoter is blocked

•Describe how alternative splicing allows for multiple gene products to be produced from the same gene.

Allows different exons to be connected in different ways increasing genetic variability and allows multiple gene products. One gene sequence can produce multiple proteins due to this

•Describe the role of posttranslational protein modifications in the control of gene expression.

Acetylation of histone proteins and methylation of DNA are examples of posttranslational modifications that control gene expression by either inhibiting or accelerating it. 

•Explain how chromatin packaging affects gene expression in eukaryotes.

Tight chromatin packaging makes DNA inaccessible and therefore chromatin must be modified through acetylation to loosen histones and allow gene expression to occur. 

•Predict the effect of mutations in gene regulatory elements on gene expression.

Mutations affecting essential things like ATP for nucleosome sliding, enhancer, activator have a negative effect and don't allow transcription to occur

•Predict how DNA methylation patterns and histone acetylation will affect gene expression.

DNA methylations stop gene expression while histone acetylation enhances gene expression

•Interpret the results of an electrophoretic mobility shift assay (AKA “EMSA” or “gel shift assay”).

•Locate the ENCODE Regulation track on the human genome browser to view experimentally measured levels

of histone acetylation for different genes.

•Determine the function of a given gene from information provided in the genome browser.

•Interpret histone acetylation information in the genome browser to determine whether the expression of a gene

is activated in a given cell type.