Chapter 19: Control of Gene Expression in Eukaryotes Flashcards
What is differential gene expression?
cells with the same genome express different sets of genes
What does differential gene expression do?
- creates different cell types
- arranges cells into tissues
- coordinates activity
What are the four additional levels of gene regulation in eukaryotes?
- chromatin remodeling
- RNA processing
- mRNA stability
- protein degradation
What is chromatin remodeling?
genes must be made accessible
What is RNA processing?
splicing can create different combos of exons
What is protein degradation?
proteins can be marked and destroyed
What is mRNA stability?
mRNAs can be blocked or degraded
Describe histones.
DNA wrapped around proteins called histones
What is a nucleosome?
DNA + histones
What are the 3 ways chromatin is altered during gene expression?
- DNA methylation
2.Histone acetylation - chromatin-remodeling complexes
What is DNA methylation?
- methyl groups (CH3) added to C nucleotides
- catalyzed by DNA methyltransferases
What does methylation do?
- condenses chromatin
- low methylation near promoter: increase transcription and vice versa
What is histone acetylation?
- acetyl groups are added to lysine on histone tails
What are histone acetyltransferases?
- HATs
- add acetyl groups, open DNA
What are histone deacetylases?
-HDACs
- remove acetyl groups, close DNA