CpG, methylation Flashcards
When there’s a C followed by a G what often happens?
It’s often methylated
What enzyme methylates CG sites?
DNA methyltransferase, recognizes CG sites?
Around how many CpGs are methylated?
Around 85%
Unmethylated CpGs are clustered where?
In CpG islands in the genome
What are CpG islands?
are CG pairs that changes methylation status
CpG islands are usually found where in mammalian DNA?
In promoters, can also be found in genes (intragenic) and outside of them intergenic
CpG islands are generally _____ in expressed genes
unmethylated
CpG islands are generally _______ in unexpressed genes?
methylated
What are unmethylated CpG islands associated with?
Associated with open chromatin and active transcription
What are methylated CpG islands associated with?
Associated with closed chromatin and repressed transcription
What proteins increase or decrease transcription in methylated and unmethylated CpGs
Methylation of CpG’s prevents transcription factor binding
Methylation creates binding sites for histone deacetylase- removes acetylase- inhibits transcription
How is DNA methylation inherited?
DNA methyltransferase methylates the other C if the first C in the original template is methylated
How does DNA methylation and histone modification contribute to epigenetic inheritance?
These don’t change original gene sequence but change stuff on top of it and therefore change patterns of expressions
What is a maternally imprinted gene?
Even though there’s two copies of a gene only one copy gets expressed
If the Igf2 gene is maternally imprinted what happens to this gene derived from the mother? The father?
The Igf2 gene derived from the mother will be silnced but expressed when derived from the father
Why is imprinting an epigenetic mechanism?
Because an identical gene will be active or inactive based on whether mom or dad gave it
What are roles of genes that are expressed in a parent of origin manner?
tend to have roles in embryonic growth and development
Why is a maternally imprinted gene silenced from the mother?
The maternal copy is methylated so it’s not expressed
How did the dutch hunter winter famine effect the methylation of IGF2?
embryos during this time had severe less methylation of IGF2.
