Exam 2: Genetic Regulation by Chromatin Structure Flashcards Preview

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Flashcards in Exam 2: Genetic Regulation by Chromatin Structure Deck (20)
1

all eukaryotes have their DNA packed by...

protein in chromosomes made of chromatin

2

fundamental unit of chromatin

nucleosome with its histone octamer core

3

2 functions of histone octamers

DNA packaging

gene regulation

4

histones are as important in gene regulation as...

transcription factors

5

do histones and TFs interact?

yes

6

how does DNA packing control gene expression?

genes can't be expressed when they are wound tightly

7

2 ways histones help control chromatin structure

histone type switching

histone tail modification

8

protein tails are where...

modification occurs

9

HFD

histone fold domain where histones bind to each other

10

histone type switching

some histones have special alternative versions (varients)

switching to a different type of histone can have a big effect on the chromatin

11

macro-H2A

completely represses transcription

shuts down genes that make a stem cell able to differentiate

12

where is macro H2A found

heterochromatin near the centromere

inactivated x-chromosomes (barr body histone varient)

genes required for reprogramming cells

13

what happens if macro-H2A is removed from the genes that make a stem cell able to differentiate?

the cell becomes an induced stem cell

14

special feature of histone modification

have loose tails (n-terminal ends) that hang out of nucleosome

programmable by histone modification

15

modifications occur most often on the aa...

lysine, which is common in histone tails

16

how do acetyl groups modify?

loosen chromatin, promoting transcription

17

how to methyl groups modify?

condense chromatin, shutting it down

18

what other molecular attachments affect histones?

phosphorylation

sumolyation

ubiquitylation

19

do enzymes make changes in histone modifications?

yes

effects may be triggered at one location and then spread from that point along DNA

20

general idea

transcription can be promoted by loose chromatin or inhibited by tight chromatin