1Central dogma of molecular biology
DNA (transcription with RNA polymerase) to RNA to Protein (using ribsosome)
2Post transcriptional modification is done using
Post transcriptional modification is done using non-coding RNAs
3Post translational modification is done using
Post translational modification is done using mRNA modification enzymes
4Methylation can occur at the and level
Methylation can occur at the DNA and histone level
5DNA, Histones, Both?
Methylation‐
DNA, Histones, Both?
Methylation‐ Both DNA and histones
6DNA, Histones, Both?
Acetylation‐
DNA, Histones, Both?
Acetylation‐ only histones
7DNA, Histones, Both?
Deacetylation –
DNA, Histones, Both?
Deacetylation – only histones
8Methylation can change the segment without
Methylation can change the activity of a DNA segment without changing the sequence
9DNA methylation typically acts to
DNA methylation typically acts to repress gene transcription
10In DNA methylation
‐ A methyl group is enzymatically added to via specific
‐ is usually the recognition sequence
In DNA methylation
‐ A methyl group is enzymatically added to cytosines via specific methyltransferases
‐ CG is usually the recognition sequence
11Methylated bases serve as binding sites for
Methylated bases serve as binding sites for methyl‐CpG‐binding domain proteins (MGDs)
12MGDs , , and also recruit
• DNA methylation usually functions to block transcription
MGDs block transcription factor assembly, block chromatin remodeling, and also recruit histone deacetylases
• DNA methylation usually functions to block transcription
13Methylation is ‐specific
Methylation is cell and tissue‐specific
14Pattern of methylation is unique in each person and is somewhat influenced by
environment
‐ Total collection of DNA structural alterations =
Pattern of methylation is unique in each person and is somewhat influenced by
environment
‐ Total collection of DNA structural alterations = epigenetics
15DNA methylation can be used in
DNA methylation can be used in animal cloning
16In animal cloning, demethylation is which means that the animals die young because they started with certain genes turned off (similar to in adult)
In animal cloning, demethylation is never complete which means that the animals die young because they started with certain genes turned off (similar to in adult)
17Histone methylation acts to
Histone methylation acts to repress gene transcription
18Histone methylation occurs on the amino acids
and in the histone
protein
Histone methylation occurs on the amino acids
Lysine (K) and Arginine (R) in the histone
protein
19Histone methyltransferases,
transfers methyl groups from onto the or
residues of the histones
Histone methyltransferases,
transfers methyl groups from S‐Adenosyl
methionine (SAM) onto the lysine or
arginine residues of the H3 and H4 histones
20Removal of methyl groups is done by
Removal of methyl groups is done by histone demethylase
21Histone : the on/off switch for gene expression
Histone acetylation and deacetylation: the on/off switch for gene expression
22Acetylation occurs when residues with get acetylated or deacteylated.
Acetylation occurs when lysine residues with N terminal tail get acetylated or deacteylated.
23Acetylation =
Acetylation = activation
24With ‐> DNA is released from histone for transcription
With Acetylation ‐> DNA is released from histone for transcription
25With ‐> DNA packs tightly around histones
With Deacetylation ‐> DNA packs tightly around histones
26Acetylation ‐> the transfer of an acetyl group to a residue on a histone
• Enzyme ‐>
Acetylation ‐> the transfer of an acetyl group to a lysine residue on a histone
• Enzyme ‐> histone acetyltransferase (HAT)
27Deacetylation ‐> removal of the acetyl group from the lysine on the histone
• Enzyme ‐>
Deacetylation ‐> removal of the acetyl group from the lysine on the histone
• Enzyme ‐> histone deacetylase (HDAC)
28Transcription factors are
Transcription factors are proteins/enzyme
29Gene regulatory transcription factors ‐> proteins that bind to DNA and directly alter the
recruitment/ binding/movement of and
Gene regulatory transcription factors ‐> proteins that bind to DNA and directly alter the
recruitment/ binding/movement of basal transcription factors and RNA pol
30Transcription factors are required to and for transcription!
Transcription factors are required to bind the promoter and recruit RNA pol for transcription!
31Enhancers and repressors are that
bind enzymes to .
Enhancers and repressors are DNA sequences that
bind enzymes to promote or stop transcription.
32DNA‐binding to enhancer bends it to allow for
DNA‐binding to enhancer bends it to allow for
transcription.
33Epigenetics
• Alterations to DNA that affect , but do not
.
Epigenetics
• Alterations to DNA that affect expression, but do not
change the code.
34The two main components of epigenetics is and .
The two main components of epigenetics is DNA
methylation and histone modifications.
35Hypomethylation associated with many
• the loss of the methyl group in the
Hypomethylation associated with many cancers.
• the loss of the methyl group in the 5‐methylcytosine
nucleotide
36TEST QUESTION
Epigenetics is a term to describe and associated alternations in gene expresssion that are or
TEST QUESTION
Epigenetics is a term to describe chromatin changes and associated alternations in gene expresssion that are not due to mutation or changes in the DNA sequence
37 >the process by which only one copy of a gene in an individual (either from their mother or their father) is expressed, while the other copy is suppressed. This impacts .
Imprinting >the process by which only one copy of a gene in an individual (either from their mother or their father) is expressed, while the other copy is suppressed. This impacts transcription.
38What is Prader-Will syndrome? What is missing? What does it cause?
-Genomic impriting in humans
-Small region in long arm of chromosome 15 is missing from FATHER
-People feel a constant state of hunger
39What is Angelman syndrome? What is missing? What does it cause?
-Genomic imprinting
-It is also due to a small region in long arm of chromosome 15 is missing from MOTHER
-Frequent laughter, large mouth
40What is Silver-Russel syndrome? What chromosome is impacted? What does it cause?
Change in chromosomes 7 or 11 in about 60% of people with the condition
• genes that control growth
41What is Beckwith-Wiedemann syndrome? What chromosome is impacted? What does it cause?
-Caused by changes on chromosome 11p15. 5
-Overgrowth syndrome
42Lifestile and diets can affect epigenetics because they can be
Lifestile and diets can affect epigenetics because they can be methyl donors.
43In the study done on the men with protsatse cancer, intense changes in life-style were seen to cause (RAN) and was upregulated (ZNF250)
In the study done on the men with protsatse cancer, intense changes in life-style were seen to cause cancer downregulation (RAN) and new protein building was upregulated (ZNF250)
44Transcendental Meditation (or just plain rest for 20
mins/day) alters
Transcendental Meditation (or just plain rest for 20
mins/day) alters telomerase expression