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Flashcards in Transcription II Deck (52):
1

what is capping

complex of 3 enzymes form a complex with pol II and modfy the 5' end of pre-mRNA into a cap

2

function of cap

allows cell to distinguish mRNA from other types of RNA

3

spilceosomes

recognize boundaries between exons and introns, catalyze cleavage adn rejioing of RNA molecule

4

another name for spliceosome

snRNP

5

what 3 sites are important for splicing to occur

5' splice site
3' splice site
branch point w/in intron

6

splicing reaction

1) adenine residue attacks 5' splice site, cutting the sufar-phosphate bakcbone
2) 5' end covalently attachs to adenine nucleotide, making a loop
3) 3' end reacts with 5' end of next exon, joing together and releasing intron

7

functino of splicing

allows more than 1 protein produce to be generated from a single pre-mRNA transcript

8

differential/alternate splicing

pre-mRNA molecule can be spliced together generating different mRNA molcules

9

polyadenylation signal

3' end of RNA specified by DNA signal

10

function of poly A tail

determinat of mRNA stability

11

is the poly A tail found elsewhere besides mRNA

no

12

where does mature mRNA need to go to be transalted

cytoplasm

13

what governs the stability of an mRNA molcule

its nucleotide sequence

14

how does degradation of mRNA start

shortening of poly A tail, triggers removal of 5' cap

15

what degrades the mRNA molecule from both ends

ribonucleases

16

how do you get beta-thalassemia

incorrect splicing

17

symptom of beta-thalassemia

profound anemia

18

mutation found in PKU patients

single base change in 5' splice donor site of one particular intron

19

function of chromatin iremodeling complexes

protein machines tha tuse energy of ATP hydrolysis to change structure of nucleosomes temporailyt so DNA becomes less tightly bound to histone core

20

how do HATs affect histones

reduce net positive change, decreases strength of their interaction with DNA

21

affect of HDACs on histones

catalyze removal of acetyl groups from histone. inhibit transcription

22

what happens when cytosine residues in DNA are methylated

produce 5' methylcytosine

23

where do proteins usually bind to DNA

major groove

24

helix-turn-helix proteins

2 alpha helices conencted by a short chain of amino acids. side changes are important in DNA pbinding

25

characterisc of zinc finger protein

zinc required for protein folding and function,
alpha helix makes contact with the major groove of DNA

26

example of zinc finger DNA binding protein

glucocorticoid receptor

27

leucine zipper protein characteristic

alpha-helix that has a leucine hydrophobic residue protruding down one side.

28

examples of leucine zipper protein

fos and jun

29

LDL recptor

glycoprotein that spans plasma membrane

30

waht does the LDL receptor gene recognize

apolipoprotein B and E

31

binding of apolipoprotein B or E with LDL receptor gene results in what

endocytosis of receptor
uptake of LDL and VLDL into cell

32

what is the relationship between LDL receptor gene and cholesteral

it's icnreased in response to low cellular cholesterol

33

what happens when you have increased transcription of LDL receptor gene

enchanges cholesterol uptake form blood

34

what does the promotor of LDL receptor gene have

SRE-1

35

function of SP-1

help with assemby of pol II and general transciription factors at TATA box

36

what addition protein does SP-1 need in order to function

CRSP

37

what is SRE-1 bound to

SREBP-1a

38

what is SREBP-1a

leucine zipper protein

39

what happesn to LDL receptor gene when cholesterol levels fall

entery of SREBP-1a into nucleus, where it binds to SRE-1, recruits HAT, relaxes chromaton allowing LDL transcription

40

what else does SREBP-1a do

binds to promoter regions of genes involved with metabolism of both choelsterol and fatty acids

41

what is the major glucocorticoid secreted in humans

cortisol

42

what happens when cortisol binds to glucocorticoid receptor

allows uptake of hormone/receptor complex into nucleus

43

GRE

where hormone/receptor complex binds, an enchancer element

44

in most tissues what do thyroid hormones do

stimulate metabolic rate

45

where are receptors for thyroid hormone found

constituvtively in nucleus

46

thyroid hormones receptors often bind to DNA as waht

heterodimers

47

what is the other part of the thyroid hormone dimer

RXR

48

complex of thyroid recpetor/RXR do what

recruit HDAC activity

49

what happens when thryoid hormones binds to thyroid receptor/RXR compelx

displacement of HDAC, binding of AHT complex, favors relaxation of chromatine sturucture which facilitates trasncrition

50

symptom of rubinstein taybi syndrome

intellectual disability, abnormality

51

what is rubinstein-taybi caused by

point mutations, small deletions and rearrangedment within genes encoding CBP or EP300

52

tamoxifen

compeititve inhibitor of estrogen receptor, used for breast cancer treatment