Histones and Nucleosomes
DNA is wound _________ times around histones
1.67
The packaging ration of the 30nm fiber and above is ~_________
1000
The ____________ (beads on a string) is comprised of the nucleosome
10nm fiber
If you do a limit digest (prolonged) of the nucleosome, you get it down to ______ bp
146
Nucleosomes contain _____ copies of each of the four histones
2
If you do a mild (average) digest of the nucleosome, you get ______ bp
200
The nucleos contains ~ ______ bp
200
To get a protein to go to the nucleus _________ amino acids must be basic
3/5
The ________ is formed from a coil of the 10nm fiber
30nm fiber
The packaging ratio of the 30nm fiber is ~_____
40
The packaging ratio of the 10nm fiber is ~____
6
Chromatin is composed of _____________ Protein, _____________ DNA, and ______________ RNA
60% 30% 10%
The linker DNA between nucleosomes is ________ bp
8-114
________ is involved in assembly of nucleosomes in both laging and leading strands
ASF1
__________ is a critical protein in nucleosome assembly and binds to H3/H4 tetramer
CAF1
Both _______ and ________ are a part of replication dependent nucleosome assembly
CAF1; ASF1
__________ recruit the pre-initiation complex and acts on the promoter
Enhancers
________ goes in front of the polymerase and release the H2A/H2B dimer (takes the cap off), disassembling the nucleosome
FACT
True or False: Histones in the nucleosome have tails
False
True or False: The 30nm fiber exists in archae
False (because there is not H1 for the 10nm fiber to wrap around)
True or False: the 30nm fiber exhibits a solenoid structure
False; it is a zig-zag 2 start helix
True or False: Chemical modifications on the histone tails are heritable
False; only chemical modifications of the DNA are
True or False: Archae have histone H1
False; thus they have no 30nm fiber
The 30nm requires the typical nucleosomal histones plus ______
H1
_______ is critical to transfer from 10nm fibers to 30nm fibers
H1
H___/H____ is a dimer
H2A/H2B
In forming the full nucleosome, H3 makes contact with ______
H3
The two most highly conserved proteins in evolution are _______ and ______
H3 and H4
Histone _________ more directly affect transcription
H3s
Histone _________ are more associted with nucleosome assembly
H4s
Histones are acetylated/deactylated by _____________/___________
HATs/HDACs
Instead of using CAF1, H3.3 uses _________ in nucleosome assembly
HIRA
____________ of the protein part of chromatin is comprised of histones
Half
_______________ replaces histone H3 in non-differentiating cells after transcription
Histone 3.3
_________________ are sequences in the genes that attract proteins that limit neighboring genes from also being activated
Insulators
Histone are methylated by _____________
Methylases
____________ is a longer term modification histone modification
Methylation
_________________ cuts at the linker DNA between nucleosomes
Micrococcal nuclease
The ______ terminals of histone tails are modified
N-
________ and _______ proteins are required to assist in the assembly of nucleosomes
Nucleoplasmin; N1
CAF1 is recruited to the replication fork by ________
PCNA
___________ and ____________ are short term modifications of histones
Phosphorylation and Acetylation
What is the size of RNA polymerase relative to the nucleosome?
RNA polymerase is larger
Why don't archae have histone tails?
Their DNA is always open in the 10nm fiber
True or False: RNA polymerase displaces histones during transcription
True
Nucleoplasmin and N1 proteins are ___________
acidic
Acetylation is generally associated with gene ______________
activation
H3.3 is used _________ repair
after
H3 and H4 first appeared in ____________
archae
Acetylation during replication occurs on histones ___________ they are incorporated into nucleosomes
before
The H2A/H2B dimer forms a _______
cap
The histone ____________ is a helix-loop-helix-loop
fold
Replication-independent nucleosome assembly utilizes a ______________
histone H3 variant
Phosphorylation is mediated by ______________
kinases
H1 binds to the ________
linker DNA
The ___________ is the fundamental unit of structure for the chromosome
nucleosome
Nucleosomes are __________ when transcription passes through a gene
reorganized