Chapter 4 Flashcards

Question

DNA Methylation

Answer 1

DNA methylation: ○ Transfer of methyl group (take cytosine and add methy group) - § Adding the methyl group changes someone and their lifespan ○ Whatever happens in your lifespan, if they do this methylation, it can be passed onto generations ○ When you have stressful experiences, sometimes they're so bad they last through the lifespan --- can they be passed on to offspring?

Answer 2

*know what is methylation (adding methyl group to cytosine and it's the backbone of DNA) process: - DNA with gene transciption turns gene on - if you add methylation on DNA, the gene transciption can be blocked (gene off) - methylation can also reduce gene transcription (gene dimmed but not off)

Answer 3

HELP can alter how teh gene responds to the environment ultimately, epegentic markings will be mixers (change the gene expression but also can dim or intensify the gene)

Answer 4

when gene is switched on = unmethylated state - active chromatin (unmethylated cytosines) - when you add methyl group (DNA closes up) - silent chromatin - methylated cytosines DNA = negative ○ Histone = positive ○ When you move the charge it loosens up - When you add the charge, the DNA closes back up

Answer 5

maternal care can alter epigenome paper: studied parental care - They noticed that if a mom was attentive and licking/grooming their animal, that animal will be less stressed later in life - The moms that were more neglectful, those animal grew up and showed more stress and anxious behavior

Answer 6

- There's not that much a rat can do to exhibit maternal care except lick, feed, groom - So you measure the time of the rat enagaging in that behavior - They thought there was an epigenetic event (during first week of life) that the mom was doing that was changing the genes for anxiety - So when the animal grows up, it can be altered

Answer 7

classified maternal care: ○ Measured the time on the nest of the mom grooming, licking, etc. (during first week of life) ○ They get the curve (those that are 2 SD on the right and left are the good and then bad moms) groups: Those raised by the higher tail end of the graph were more relaxed and had better coping behavior *a pup raised by anxious, low nurturing mom, becomes anxious adult **pup raised by relaxed, high nurturing mom becomes relaxed adult

Answer 8

Pathway of Stress: - CRH cells in hypothalamus release CRH into pitutiary - Those cells release ACTH which causes release of cortisol - That goes back into the hippocampus A lot of our emotions (fear, hurt) are processed by the amygdala ○ That activates the hypothalamus ○ That releases cortisol and then that goes up to hippocampus - The hippocampus reads the cort. says we have to dampen the stress response

Answer 9

Secretes ACTH, cortisol comes out and goes into the hippocampus to dampen it study: maternal care can change glucocorticoid receptor expression and stress response *** - The pups from good maternal care have high gluc. Recpetors (respond to the increase of - Hippocampus is involved in stress response -- has gluc. Receptors and then responds and tells cells how they should act

Answer 10

looked at methylation on gluc. gene If you measure amt. of methylation prior to birth on gluc. Receptor, it's low ○ Once the animal is born, that gene is highly methylated ○ At diferent times, animals in a low maternal care environment, they remained high in methylation on that gene ○ Those in the hiugh maternal env. Had reduced methylation on that gene Rats go thru pubtery arbound p40 ○ The change in methylation that happens from the high/low licking environment, stays in their adult life *if you have lower methylation, you get a higher output (protein goes up) *that higher GR = more adaptive *low GR = less adaptive

Answer 11

made enclosure for rat to not be able to move - rats don't like being in the light if you put the rat in a tube, they want to stimulate a burrow collapse where they can't move ○ Stress we don't have control over is worse than stress we do have control over ○ If you measure cortisol before to being enclosed, it's low ○ You put the animal in tube, within 15 minutes, a cortisol response happens (it goes up and then goes down within an hour) ○ **classic way to measure stress response

Answer 12

*low GR in hippocampus, lower feedback, cort is not reduced in response to stress *if you do this with animals from mom with high licking vs low licking -- there's differences *cort goes up *those from the low licking group, their cortisol goes up higher and their ACTH goes up - It stays higher for low licking group - For high licking rats, their stress goes up, but it does go back down ***if you have lower gluc. Recpetors in the brain, you won't have as good of a stress response when you get stressed

Answer 13

- The variations in maternal care can alter the gluc. Receptors, cause methylation, and alter stress response - Less methylation on GR gene, leads to high expression of GR and low anxiety - Opposite for rats with low licking (low maternal care) - High maternal care: ○ "licking" away the methyl marks ○ Increased GR in hippocampus, better stress response Low licking: ○ Mark stays ○ Animal will be anxious later in life

Answer 14

If you methyl the area of the promoter region, it blocks the transcription factor from binding to the gene by closing it (physical process) --- closes the DNA so it can’t be read or transcribed - Low methylation, less transcription factor binding, less gene expression, high anxiety *if you have higher GR, you have low corticosterone levels and high licking or grooming (opposite for lower GR)

Answer 15

weight is important in babies - if you hold babies, they will gain weight faster ○ By measuring change in weight is important (released faster from nicu) § Has health implications § Those with increased contact perform better academically § Those that didn't have contact do worse and have lasting impacts

Answer 16

**mom licks male rats a little more than female rats - She licks the anal/genital region because those animals have hard time to eliminate waste and the sensory touch helps them - Males have testes (secrete androgens) that changes the acidity of the urine ○ Something that the androgens is doing that changes the urine - Estrogen receptors in brain: ○ Females have more than males in some areas ○ More estrogen receptors in RNA or protein ○ Sex difference in estrogen receptor and protein

Answer 17

- Tested by holding rat first few days of life, and stroked anal/genital region ○ The paintbrush stroking mimicked the licking ○ The controls were just held (not stroked) - Androgen receptors -- get masculinized by the licking ***maternal licking increases methylation and decreases estrogen receptor expression

Answer 18

- Females that receive the extra licking, had closer to female like control levels ○ The licking and grooming stimulated pattern, made higher ○ In simulation: painting on methylation marks § A stimulus can lead to different directions of promoter genes - Maternal care: mom licks off methylation (doesn't lick off all of methyl marks)

Answer 19

- SRY gene increases SOX-9, makes testes which secretes tesosterone - That increases the urine diff. which causes the mom to lick them more -- The SRY gene can manipulate the mom to come over and change how that rat is being raised (being licked more)

Answer 20

○ Oxytocin receptor research ○ She found that babies that are near attentive caregivers show reduction of epigenetic modification on the oxytocin recpetor gene (lowered methylation) ○ Oxytocin is involved in bonding § Oxytocin went down when cared for more ○ The reduction lasted at least the first 18 months of the baby's life ○ ***how you care for a baby can have a big effect later on in life ○ Touch is very poweful for a baby

Answer 21

- Increased maternal oxytocin levels were when the mom was more affectionate to the baby - parents with higher oxytocin levels showed more sychrony and responsiveness to their infant interaction Paternal oxytocin levels: - Increased oxytocin levels when there was more physical contact *differences in how parents interact with their baby

Answer 22

BDNF is important for neurons to survive and grow ***it can be a neurotransmitter modulator and is important for neural plasticity (needed for learning and memory) they looked at BDNF consequences of binge drinking - BDNF is a good protein - if you sleep, increases BDNF - *cortisol acts against BDNF (low BDNF when stressed)

Answer 23

study found that found that adolescent drinking can epigenetically alter BDNF **teen drinking lowers BDNF **they found another gene increases from bindge drinking (this is an anti-sense (BDNF anti-sense) -- this lowers BDNF *ppl older than 21 -- drinking doesn't really affect BDNF as much

Answer 24

Our bodies can produce anti-sense molecules - Little RNA molecules that don't code - They might target an RNA and form a hybrid -- cells hate double-stranded RNA so it has cells go and break up the RNA hybrid and then gets degraded - So if you have an increase in anti-sense BDNF, it will bind to BDNF and then make a hybrid, the cells will degrade it and then you won't make BDNF

Answer 25

- Exposed adolescent female and male rats to alcohol - After they were sober, they were mated and then they looked at the offspring *they raised the offspring and then looked at their social interactions results: ***they found that those parents that engaged in alcohol abuse prior to conception, they weighed less - The rats with parents exposed to alcohol, the offspring played less - ***effect that impacted the gametes that when they fertilized, there was an impact of binge drinking prior to conception **in males, binge drinking effects methylation on sperm

Answer 26

Methyl donors - mythlation comes from methionine, folate, vitamin D, etc… - Our diet is responsible for the methylation of DNA foods high in folate: beans, rice, spinach - folate allow for the enzymes to drop methylation onto our DNA

Answer 27

BPA is in a lot of things (waterbottles, toys) - when you heat plastic, BPA gets into it BPA = endocrine disrupter - binds to estrogen recpetors but then causes them to be a diff. shape - it twists differently - Interacts with different coactivators and then works differently ***endocrine disruptor

Answer 28

all mammals have agouti gene = makes brown rat because agouti gene has been methylated if coat color is brown = gene has been methylated Animals exposeed to BPA, results in demethylation of Agouti gene ○ Removal of methylation, animal becomes yellow, risk to obesity and cancer - The coat changes (you can see when it's methylated or not) study: moms fed low or high BPA - if mom gets fed high BPA, then offpspring looks more yellow and is heavier if you make diet that increases methylation: ***they found that the high methyl diet blocked the cosequences of BPA (***if you consume BPA but also get high methyl diet (from folate), then the effects of the high BPA levels aren't as bad)

Answer 29

when mom's were fed BDP, their babies were more likley to be yellow and obese **when the moms were fed BPA and methyl-rich foods, the offpsring were more likely to be brown and healthy ***the maternal supplementation counteracted against the neagtive effects of BPA exposure

Answer 30

looked at identitical twins and their methylation profile 3 year olds: very similar profiles older twins: very different **when you have twins, even with the same DNA, because of epigenetics, they can have different diseases later on ex: if one has more methylation in their diet, might not get alzheimers **as they get older, their DNA sequence stays the same, but their epigenetic tags can change depending on their life

Answer 31

vassopressin study: - if you castrate, remove tesosterone, vasopresin goes away - If you give tesosterone, vasopresin goes back up - Intact animal, low promoter methylation (genes open) ***Hormones are reversing the methylation

Chapter 4 Flashcards

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