CpG, methylation Flashcards

1
Q

When there’s a C followed by a G what often happens?

A

It’s often methylated

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2
Q

What enzyme methylates CG sites?

A

DNA methyltransferase, recognizes CG sites?

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3
Q

Around how many CpGs are methylated?

A

Around 85%

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4
Q

Unmethylated CpGs are clustered where?

A

In CpG islands in the genome

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5
Q

What are CpG islands?

A

are CG pairs that changes methylation status

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6
Q

CpG islands are usually found where in mammalian DNA?

A

In promoters, can also be found in genes (intragenic) and outside of them intergenic

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7
Q

CpG islands are generally _____ in expressed genes

A

unmethylated

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8
Q

CpG islands are generally _______ in unexpressed genes?

A

methylated

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9
Q

What are unmethylated CpG islands associated with?

A

Associated with open chromatin and active transcription

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10
Q

What are methylated CpG islands associated with?

A

Associated with closed chromatin and repressed transcription

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11
Q

What proteins increase or decrease transcription in methylated and unmethylated CpGs

A

Methylation of CpG’s prevents transcription factor binding
Methylation creates binding sites for histone deacetylase- removes acetylase- inhibits transcription

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12
Q

How is DNA methylation inherited?

A

DNA methyltransferase methylates the other C if the first C in the original template is methylated

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13
Q

How does DNA methylation and histone modification contribute to epigenetic inheritance?

A

These don’t change original gene sequence but change stuff on top of it and therefore change patterns of expressions

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14
Q

What is a maternally imprinted gene?

A

Even though there’s two copies of a gene only one copy gets expressed

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15
Q

If the Igf2 gene is maternally imprinted what happens to this gene derived from the mother? The father?

A

The Igf2 gene derived from the mother will be silnced but expressed when derived from the father

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16
Q

Why is imprinting an epigenetic mechanism?

A

Because an identical gene will be active or inactive based on whether mom or dad gave it

17
Q

What are roles of genes that are expressed in a parent of origin manner?

A

tend to have roles in embryonic growth and development

18
Q

Why is a maternally imprinted gene silenced from the mother?

A

The maternal copy is methylated so it’s not expressed

19
Q

How did the dutch hunter winter famine effect the methylation of IGF2?

A

embryos during this time had severe less methylation of IGF2.

20
Q
A