Exam 2: Gene Regulation in Eukaryotes Flashcards Preview

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Flashcards in Exam 2: Gene Regulation in Eukaryotes Deck (28)
1

# prokaryote genes vs. # eukaryote genes

prokaryotes have ~500-5000 genes

eukaryotes have ~6000-30,000 genes

2

how does genetic control begin?

with a promotor (both prokaryotes and eukaryotes)

promotor longer in eukaryotes

3

how is promotor strength determined?

binding affinity of the promotor

4

transcription factor

any protein that affects transcription (regulates gene expression)

5

how do transcription factors work?

bind a target site in DNA or bind another TF or both

6

what are TF DNA-binding sites called?

enhancers

7

can the same protein act as an activator or repressor in different circumstances?

yes

TFs can also act simultaneously in two places side by side on DNA

8

TF binding sites can be...

near promotors they regular

far away from promotors they regulate

upstream or downstream of transcription unit they control

9

can TF binding sites be in introns?

yes

10

two ways TF regulate genes

direct effects on the transcription complex

spreading effects on chromatin geometry

11

cis regulation sites

sites in DNA close to a gene, which code for TF binding sites

12

trans regulation sites

site in DNA far away from a gene, which code for TF proteins

13

what does trans mean

gene that codes for it is found somewhere else

it could be anywhere in the genome

14

what kind of effects do changes in the cis/trans part of the regulatory system have?

phenotypic effects

15

CRM

cis regulatory module/enhancer

cluster of TF binding sites

16

effects of CRM

converge on the promotor

17

what is a CRM

small region of DNA (500bp) with 5-15 binding sites for TFs

18

how long are the individual TF binding sites in a CRM

6-10 bases long

19

are CRMs on the same DNA as the gene they regulate?

yes, but they can be distant from the gene if they're on the same dsDNA strand

20

are genes controlled by a single CRM or multiple CRMs?

either

21

why is on-off control of the same gene from different CRMs needed?

b/c many genes get used in more than one place

22

interactions between TFs that control genes by CRM

combinatorial control

cumulative effects

competitive binding

23

how do TFs bind dsDNA?

in the major groove they recognize target base sequences and bind to them

they dimerize and bind to palindromes in the major groove

24

DNA palindrome

5' GAATTC 3'

3 'CTTAAG 5'

25

mammals have how many TF proteins?

2500

it takes a lot of genes to control a lot of genes

26

does each TF have its own transcription unit?

yes

27

leucine zipper

two crossed helices holding DNA

28

how far away can control sites in DNA be from the gene they control?

up to 30,000 bases away and sometimes even farther