T3A2 Flashcards

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1
Q

Short term responses in the target cell

A

modify immediate cell processes, (i.e. metabolism,
movement) Can include post- translational protein
modifications

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2
Q

Long term responses in the target cell

A

Modification of gene expression and/or
development

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3
Q

Genome is

A

inherited

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4
Q

Epigenome can be

A

altered

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5
Q

Chemical DNA modifications that occur along the genome

A

change gene activity without altering the DNA
sequence

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6
Q

Epigenetic processes are essential for

A

normal development, cell differentiation, and are increasingly being recognized as being involved in human diseases

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7
Q

Epigenetic mechanisms

A
  • Modifications of histone tails (Alters wrapping of DNA around histones)
  • DNA methylation (alters ability of transcription factors and RNA polymerase to interact with promoter)
  • Overall result: Chromatin remodeling
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8
Q

Epigenomics

A

studying the epigenetic modifications across an individual’s entire genome and relate them to cell
function and even disease

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9
Q

Cancer cells abnormal genomes

A

lower levels of methylation, increase expression of genes that promote cell growth or higher levels of methylation decrease expression of genes that keep cell growth in check or repair DNA or initiate cell death

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10
Q

Cancer can begin when

A

mutations change a cell’s DNA sequence, abnormal epigenomes, expression of some genes are turned up and some are turned down – often in the very same cells

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11
Q

Agouti gene encodes

A

protein that signals to melanocytes to switch from producing black to yellow pigment

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12
Q

Agouti yellow mice have insertion in

A

Agouti gene, making them obese and yellow, and pre-disposed to diabetes, and cancer

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13
Q

In normal healthy mice (brown), the agouti genes are

A

kept off due to DNA methylation

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14
Q

In genetically identical obese sibling (yellow), the same
genes are

A

not methylated…leads to yellow colour… also,
predisposition to cancer and diabetes

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15
Q

Nutrients

A

silence the Agouti gene but do not alter the gene sequence

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16
Q

What alters coat colouration and disease
susceptibility?

A

Maternal dietary supplementation of Agouti mice with methyl donors (i.e. folic acid, choline, vitamin B12)

17
Q

Genetically identical littermates can range in colour across a spectrum of yellow to mottled to brown mice due to

A

epigenetic variations established in the
womb

18
Q

Identical twins

A
  • Identical or monozygotic twins =1/250 live births
  • A single fertilized egg divides into two separate embryos
  • Identical twins inherit the exact same genes from their parents
19
Q

Adding B12, folic acid, methyl sources helps closure of spinal cord leading to

A

Decrease in spina bifida and neural tube deficiences

20
Q

noticeable differences in facial aging in twins can be caused by

A

smoking history, environmental cues with aging causing changes in gene expression

21
Q

Monozygotic twins share

A

common genetic blueprint, but have different phenotypes that can be influenced by epigenetic modifications

22
Q

Study done in spain

A

Set out a call for monozygotic twin pairs, young and old, look at level of epigenetic differences old vs young

23
Q

Study method

A
  • 40 volunteer Caucasian twin pairs from Spain
  • Age range: 3-74 years of age
  • Profiled epigenetic patterns of DNA methylation, & histone protein acetylation. Microarray analyses
24
Q

Mapping of chromosomal regions for DNA methylation
reveals

A

differential methylation in twin pairs

25
Q

Mapping technique

A

Competitive hybridization with normal
metaphase chromosomes

26
Q

The 3-year-old twins show

A

very similar distribution of DNA methylation (indicated by lots of yellow which shows equal amounts of green and red dyes)

27
Q

50-year-old twins show

A

abundant changes in the pattern of DNA methylation observed by presence of green and red signals which show hyper and hypo-methylation

28
Q

Older twin pairs also show

A

large differences in histone acetylation

29
Q

Epigenetic drift

A

failure to transmit epigenetic information through successive cell divisions in our bodies

30
Q

Dr. Parminder Raina

A

Relating specific epigenetic markers along the human epigenome to health-related, social and environmental mechanisms, with the goal of identifying genes that appear to be sensitive to epigenetic alterations with age

31
Q

Dr. Parminder Raina goal

A

Recruited 50 000 people from across Canada to take DNA and looking at epigenome. What are genes that are sensitive to epigenetic mechanisms?