F lec 16 Flashcards
1
Q
_____________ _____________ ______________ marks the beginning of prometaphase
A
nuclear envelope breakdown (prophase –> prometaphase)
2
Q
in interphase, chromosome are _________________
A
decondensed (allows for transcription and DNA replication at S-phase)
3
Q
in interphase, chromosomes are decondensed, which allowed for ________________ and ______ ________________ at S-phase
A
transcription, DNA replication
4
Q
for proper chromosome segregation in anaphase, chromosomes must first be packaged into a highly ________________ form
A
condensed
5
Q
for proper chromosome _________________, chromosomes must first be packaged into a highly condensed form
A
segregation
6
Q
the ________________ complex promotes chromosome condensation in prophase - may act as a ring connecting 2 parts of a chromosome
A
condensin
7
Q
the condensin complex promotes chromosome condensation in prophase - may act as a __________ connecting 2 parts of a chromosome
A
ring
8
Q
condensin complex is activated when it is phosphorylated by _________
A
CDK1
9
Q
______ is the key initiating event of mitosis, and allows cytoplasmic proteins access to the nucleus and nuclear proteins access to the mitotic spindle
A
NEB
10
Q
NEB allows ___________________ from the mitotic spindle access to the _________________
A
microtubules, kinetochore
11
Q
intermediate filament proteins that support the nuclear envelope
A
nuclear lamins
12
Q
NEB is triggered by ________ phosphorylation of many targets including the nuclear pore complex and nuclear lamins
A
CDK
13
Q
NEB is triggered by CDK _________________ of many targets including the nuclear pore complex and nuclear lamins
A
phosphorylation
14
Q
NEB is triggered by CDK phosphorylation of many targets including the ____________ __________ _____________ and _______________ _________________
A
nuclear pore complex, nuclear lamins
15
Q
NEB occurs when __________ activity reaches its maximum level
A
CDK1
16
Q
the negative end of a microtubule is at the __________________
A
centrosome
17
Q
the _______________ end of a microtubule is at the centrosome
A
negative
18
Q
the _______________ end of a microtubule radiates out (from the centrosome)
A
positive
19
Q
the positive end of a microtubule ______________ ___________
A
radiates out (from the centrosome)
20
Q
all 3 types of microtubules start out as ______________ microtubules before they differentiate
A
astral
21
Q
microtubules that grow and shrink rapidly in prometaphase and capture kinetochores on chromosome to become kinetochore microtubules
A
astral microtubules
22
Q
when an astral microtubule captures a kinetochore, it becomes a __________________ _________________
A
kinetochore microtubule
23
Q
microtubules from either pole that interact in the spindle midzone, stabilizing the bipolar spindle - the sliding of interpolar microtubules then allows pole separation in anaphase and these establish the site of cytokinesis
A
interpolar microtubules
24
Q
interpolar microtubules come from either pole and interact in the _______________ _________________
A
spindle midzone
25
the _______________ of ___________________ microtubules allows pole separation in anaphase
sliding, interpolar
26
interpolar microtubules establish the site of _______________
cytokinesis
27
microtubules with plus ends that associate with kinetochores at the centromeres of chromosomes - can shrink and grow by polymerization or depolymerization at plus end while still holding onto the kinetochores
kinetochore microtubules
28
kinetochore microtubules polymerize and depolymerize at the ________ end in order to grow or shrink
plus (+, positive, however the fck you wanna say it)
29
replicated sister chromatids are held together by __________________
cohesins
30
replicated _____________ _____________ are held together by cohesins
sister chromatids
31
the ________________ is the multiprotein complex that assembles at the centromere of both sister chromatids for each chromosome
kinetochore
32
the kinetochore is the multiprotein complex that assembles at the ________________ of both sister chromatids for each chromosome
centromere
33
the separation of sister chromatids requires the loss of ________________ and depolymerization of kinetochore microtubules
cohesins
34
the __________ ________________ binds to the centromeric regions of the chromosomes
inner kinetochore
35
the ____________ ________________ is thought of as acting like a collar around the kinetochore microtubule
outer kinetochore
36
the subunits of the microtubule that can be added or removed are composed of _______________ (addition or removal causes the microtubule to grow or shrink)
tubulin
37
kinetochore attachment leads to the _____________________ of kinetochore microtubules from the plus ends
depolymerization (shrinking to pull apart)
38
during depolymerization of kinetochore microtubules, the ______________ ________________ remains attached
outer kinetochore
39
_________________ is what pulls kinetochores and associated microtubules to poles
depolymerization
40
in ___________________, kinetochore attachments are unstable
prometaphase
41
in prometaphase, kinetochore attachments are ______________
unstable (so they frequently lose their attachment and must reattach)
42
due to unstable kinetochore attachment, microtubules often lose their attachments to the kinetochore and need to reattach- but in the meantime the other pole might grab it making it look like chromosomes move ______________ ________ ____________ in prometaphase
back and forth
43
in _________________, due to unstable microtubule-kinetochore attachment chromosomes appear to move back and forth
prometaphase
44
when a chromosome is successfully captured by microtubules from both poles, kinetochore attachments are ____________________
stabilized
45
proper chromosome segregation requires capture of both sister chromatids by microtubules from opposite poles, known as ____________ _______________
amphitelic attachment
46
incorrect microtubule attachment where only one microtubule attaches to one of the sister chromatids
monotelic attachment
47
incorrect microtubule attachment where both kinetochores attached to microtubules coming from the same pole
syntelic
48
incorrect microtubule attachment where only one kinetochore is attached to 2 microtubules from opposite poles
merotelic
49
______________ _____ ____________ is the enzyme that is responsible for why kinetochore attachments are unstable in prometaphase
aurora B kinase
50
aurora B kinase is inactivated by ___________ ____________ that occurs when amphitelic attachment occurs and pulls the chromatids in opposite directions to create the condition needed to inactive aurora B kinase
physical tension
51
if _____________ _____ _____________ is missing, then monotelic, syntelic, and merotelic attachments are not destablized and these chromosomes are pulled to one pole (improper segregation)
aurora B kinase
52
aurora B kinase is localized to the ______________ and phosphorylates kinetochore components leading them to bind microtubules less efficiently
kinetochore
53
aurora B kinase is localized to the kinetochore and ____________________ kinetochore components leading them to bind microtubules less efficiently
phosphorylates
54
once all of the kinetochores achieve an amphitelic attachment and aurora B kinase is inactivated and the kinetochore attachments are stabilized, the ______________ _________ must be broken for pulling force to initiate anaphase
cohesin rings
55
the completion of anaphase requires the inactivation of CDK1 by destroying _____________
cyclin B
56
the completion of anaphase requires the inactivation of ___________ by destroying cyclin B
CDK1
57
in _______________, chromosomes remain at the midzone because they are attached to eachother via cohesins
metaphase
58
in metaphase, chromosomes remain at the ______________ because they are attached to eachother via cohesins
midzone
59
in metaphase, chromosomes remain at the midzone because they are attached to eachother via _____________
cohesins
60
anaphase occurs when _____________ bonds are broken
cohesin
61
the breaking of cohesins to separate sister chromatids relies on the destruction of the protein _______________
securin
62
in anaphase the mitotic spindle pulls chromatids to spindle poles, which depends on the destruction of _______________ _____
cyclin B
63
the destruction of both securin to initiate anaphase and cyclin B to complete anaphase depends on a ______________ _____________ called the Anaphase Promoting Complex/ Cyclosome (APC/C)
ubiquitin ligase
64
the destruction of both securin to initiate anaphase and cyclin B to complete anaphase depends on a ubiquitin ligase called the ______________ ________________ ______________ ______________
Anaphase promoting complex/cyclosome (APC/C)
65
Experiment to determine whether there is a specific sequence that allows cyclin B to be targeted for degradation:
JUST READ IT
66
if the 90 aa sequence at the N-terminus of cyclin B is deleted, the protein becomes stable and mitosis arrests in ___________ ___________
early anaphase (meaning it cannot complete anaphase until cycB is degraded)
67
Experiment showing that NEB is caused by cycB:
JUST READ IT
68
if you were to add both delta90-cycB and full length cycB, the extracts have an ___________ _____________ ____________ still because not all the cycBs are degraded
early anaphase arrest
69
delta90-cycB is still able to induce entry into metaphase in xenopus extracts or eggs, but these extracts or eggs arrest in _________________
metaphase ( /early anaphase as previously stated)
70
the CDK1-cycB complex is known as _____________ _____________ _______________ and is necessary for entry into mitosis
Maturation Promoting Factor (MPF)
71
_________ activates the cyclin destruction machinery
MPF (CDK1-cycB)
72
once cyclin destruction machinery is active, it destroys cyclin and _________ is no longer active (negative feedback)
MPF
73
destruction of cycB is necessary for ___________ _________ _____________ and inactivation of the cyclin destruction machinery
exit from mitosis
74
to determine the specific sequence within the 90 aa region necessary on the cyclin they looked for ______________ ______________ within this region amongst cyclins from different species
conserved motifs
75
after looking for conserved motifs in the 90 aa region on the cycB protein, they found a ____(#) aa sequence conserved that goes __________________, and is called the ________________ _______________
9, RxxLxxxxN, destruction box
76
proving that the destruction box is ____________________:
sufficient
77
proving that the destruction box is __________________:
necessary
78
means that having this sequence without the rest of the region is enough to cause destruction
sufficient
79
means that without the sequence there the destruction wont happen at all
necessary
80
the destruction box was found to be both _______________ and ________________ for the destruction of cyclin B
sufficient, necessary
81
experiment to determine that the destruction box is sufficient to cause destruction of the protein:
protein A
82
if they added the 90 aa cycB fused with protein A to an __________________ extract, it would not be degraded
interphase
83
experiment to determine that the destruction box is necessary to cause destruction of the protein:
mutate
84
during experimentation, it was found that mutating a single amino acid in the destruction box ________ makes protein A fused to the destruction box stable again
R42C
85
as the protein A was being degraded when tagged with the destruction box, why was there a ladder of higher molecular weight form that gets detected?
polyubiquitination (of protein A to target it for destruction, every band is +1 ubiquitin)
86
the proteins __________,__________, __________ were identified as being required for anaphase progression and destruction of B-type cyclins by ubiquitination
cdc16, cdc23, cdc27
87
the proteins cdc16, cdc23, and cdc27 were identified as being required for _____________ progression and destruction of B-type cyclins by ubiquitination
anaphase
88
the proteins cdc16, cdc23, and cdc27 were identified as being required for anaphase progression and destruction of _______________ by ubiquitination
cyclin B
89
the proteins cdc16, cdc23, and cdc27 were identified as being required for anaphase progression and destruction of B-type cyclins by _________________
ubiquitination
90
__________ is an active kinase that phosphorylates the APC and this phosphorylation is necessary for the activity of the APC cdc20
CDK1
91
the subunit on the APC that actually recognizes the destruction box on the cyclin
cdc20
92
the interaction whereby the CDK1 complex activates the APC cdc20 subunit to deactivate the CDK1 complex that activates it can be described as _______________ _____________
negative feedback
93
what did Aiden Mitrevski call the erectile dysfunction of protein signaling pathways?
when the destruction box on cycB is lost so APC cdc20 keeps getting higher and higher signaling to activate but cant actually do its job because there is no destruction box to target with ubiquitin
94
the destruction of cyclin B (resulting in loss of CDK1 activity) is necessary for the movement of sister chromatids to poles in ___________ ______________
late anaphase
95
other than destroying cyclin B, it is also important to destroy ________________ (which is a target of the APC) because destroying this protein is necessary for cohesin removal and separation of sister chromatids at the onset of anaphase
securin
96
________________ keep sister chromatids together until anaphase of mitosis
cohesins
97
cohesin complexes are assembled in _____-___________
S-phase
98
_______________ requires cohesin removal
anaphase
99
the segregation of sister chromatids in anaphase depends on the breaking of cohesin complexes by _______ __________________
SCC1 cleavage
100
in defective APC mutants:
JUST READ IT
101
in delta90 cycB mutants:
JUST READ IT
102
the job of securin is to bind and inactivate a protease called ______________
separase
103
type of protein that separase is
protease
104
securin _______________ separase
inactivates
105
once the APC targets the destruction box on securin, securin gets destroyed which allows _____________ to be activated
separase
106
the target of separase is _________ component of the ________________ complex and if you break that part of the ring then it is responsible for anaphase because it allows the sister chromatids to separate and be pulled apart towards the poles
SCC1, cohesin
107
securin has a _____________ ______ that allows it to be targeted for destruction by the APC by ubiquitination
destruction box
108
Destruction box mutants of securin results in failed sister chromatid segregation and metaphase arrest that looks just like ________ __________________
APC mutants
109
Destruction box mutants of securin results in failed sister chromatid segregation and _____________ arrest that looks just like APC mutants
metaphase
110
mutants that do not produce ________________ at all segregate chromosomes prematurely and incorrectly, before anaphase
securin
111
the main purpose of securin is to ____________ _______________
prevent anaphase
112
2 purposes of the APC cdc20:
destroy cyclin, destroy securin
113
APC mutants arrest in ________________
metaphase
114
APC and securin double mutants arrest in _________ ______________ (because cyclin B not being degraded would be the thing that causes the arrest since without APC it would not be degraded but without securin at least it can leave metaphase and separate)
late anaphase
115
securin prevents anaphase by _________________ _________
protecting SCC1
116
in APC mutants, securin is ______________
stable (associated with DNA)
117
in securin mutants and in securin and APC double mutants, securin is _______________
unstable (separase do be choppin)
118
in separase mutants, SCC1 is ____________ and mitosis arrests in _______________
stable, metaphase
119
what technique did they use to find separase association with securin?
co-immunoprecipitation
120
securin and separase double mutants arrest in ______________ and have a ____________ SCC1
metaphase, stable
121
the APC is not able to ubiquitinate securin or cycB until all chromosomes are properly attached to kinetochore microtubules via _____________ ________________
amphitelic attachment
122
so what keeps the APC inactive?
SAC (spindle assembly checkpoint)
123
experiment to find the gene that codes for spindle assembly checkpoint:
JUST READ IT
124
colchicine and vinblastine are _______________ _______________ drugs
microtubule destabilizing
125
taxol is a _______________ _______________ drug
microtubule stabilizing
126
when cells are treated with colchicine, vinblastine, or taxol, CDK activity is ___________, and cyclin B and securin are ___________
high, stable
127
__________ mutants enter anaphase prematurely, before all kinetochores have attached to spindle properly (and so the cells treated with colchicine, vinblastine, and taxol that are this type of mutant will still get to anaphase)
mad2 (a type of SAC)
128
mad2 and APC double mutants behave like APC mutants and arrest at _______________
metaphase (therefore mad2 and SAC function genetically upstream of APC) (also provides evidence that SAC inhibits APC)
129
since mad2 / APC double mutants arrest at metaphase like APC mutants, it can be said that mad2 or SAC functions _______________ genetically of APC
upstream
130
a complex of proteins, called the ___________ ____________ _________________ is active at kinetochores that are not attached to spindle microtubules
spindle assembly checkpoint (SAC)
131
at kinetochores that are not attached to spindle microtubules, the SAC component ________ is activated and diffuses away to bind to cdc20 and inhibit cdc20
mad2
132
mad2, once activated, diffuses away and inhibits ________, preventing securin and cycB destruction
cdc20 (subunit of the APC)
133
kinetochore spindle attachment inactivates the SAC/mad2 component and leads to _______ activation
APC
134
model where trapezoid mad2 cycles from cytoplasm to kinetochore and back to cytoplasm and in cycling it converts from inactive form to active triangle form mad2 and then the triangle form can go bind to cdc20 and inactivate it - important thing even if it is just one chromosome that has not attached to spindle
kiss and run model
