Molecules and Mechanisms E1 Flashcards Preview

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Flashcards in Molecules and Mechanisms E1 Deck (108):
1

Resact

from sea urchin egg jelly coat, binds to a receptor on sperm to lead it to egg. 

2

RGC 

Receptor guanyl cyclase, what resact binds to. forms intracellular cGMP in sperm 

3

cGMP

in sea urchin sperm, opens calcium channels in cell membrane to let Calcium enter sperm

4

fucose sulfate

a sulfated card that binds to receptor on sperm to initiate acrosomal reaction. The receptor it binds to acivates sperm membrane proteins 

5

Three mechanisms activated in sperm during acrosomal reaction

  • Calcium transport channel that lets calcium enter sperm head
  • Na/H pump that lets Na in and H out
  • IP3 phospholipase enzyme releases calcium from inside sperm 

6

Two effects of calcium increase in acrosomal reaction of sea urchin

  • fusion of acrosomal membrane with adjacent sperm cell membrane to release digestive enzymes
  • activates protein RhoB to make acrosomal process

7

RhoB

GTP-bdinging protein in sperm that polymerizes actin to make the acrosomal process. Activated by IP3

8

Bindin

acrosomal membrane protein of sperm that recognizes and binds to surface of egg 

9

ERB1

Bindin receptor organized in complexes on vitelline envelop of egg

10

Calcium source for cortical granule reacton

calcium comes from the ER of the egg cell and is self-propagating

11

IP3

  • In sperm, releases calcium to fuse acrosomal membrane with sperm cell membrane (and release digestive enzymes); activate protein RhoB to make acrosomal process
  • In egg, releases Calcium from ER. Made from PIP2 being split by enzyme PLC

12

PIP2

Found in egg cell, split by PLC to make DAG and IP3

13

PLC

splits PIP2 to make DAG and IP3 for the cortical granule reaction. y-PLC is activated by an Src family of protein kinases in cortical cytoplasm

14

Src protein kinases

found in cortical cytoplasm of egg, activate y-PLC to generate IP3 and DAG by splitting PIP2. Activated by G proteins 

15

G proteins

found in cortex of egg, serve to activate Src kinases, which activate PLC for inducing cortical granule reaction

16

2 effects of sperm binding/fusion to egg cell membrane

  • Sodium influx
  • Kinase stimulation

17

Role of Sodium in fertilization of sea urchins

causes a change in egg membrane potential and leads to fast block to polyspermy

18

Role of kinase stimulation from sperm binding to egg membrane

activates PLC, which does lots of things

19

2 Roles of PLC in fertilization

  • IP3 production to release Calcium
  • Diacylglycerol production to increase intracellular pH

20

Role of diacylglycerol in sea urchin fertilization

activates protein kinase C, which leads to Na/H pump exchange and increase in pH

21

Protein Kinase C

found in egg, activated by diacylglycerol, leads to exchange of Na/H. Increase in Na ionsin cell causes rise in pH

22

Role of increase in pH in fertilization

together with Calcium increase, stimulates new DNA and protein synthesis

23

influx of K+ in mammalian sperm 

leads to hyperpolarization of sperm membrane potential 

24

soluble adenyl cyclase

in mammalian sperm, activated by increase in Calcium and bicarbonate in sperm. Makes cAMP from AMP

25

cAMP

activates protein kinase A

26

PKA

activated by rise in cAMP in mammalian sperm, leads to activation of protein tyrosine kinases and inihibition of PTP - phosphotryrosine phosphatase

27

PTK

leads to capacitation of mammalian sperm 

28

SED1

protein in sperm that has a slight bond to zona pellucida

29

ZP3 

glycoprotein in zona pellucida of mammalian egg that binds to sperm and leads to acrosomal reaction by causing calcium-mediated exocytosis of acrosomal vesicle

30

Cyclin B

contributes to biphasic cell cycle of cells. Makes up MPF. Synthesis of it allows progression to Mitosis, while degradation allows cells to pass to synthesis phase 

31

MPF

mitosis-promoting factor. Highest during mitosis, but can't find it during synthesis. Shift in phases of cell cycle is driven by gain and loss of this molecule's activity. 

Made of cyclin B and cyclin-dependent kinase 

leads to rapid, synchronous cell divisions 

32

Order of sea urchin first 3 cleavages

meridional, meridional, equatorial

33

Otx and B-catenin

activate Pmar1 gene in cleavage. These are maternal cytoplsm-derived Transcription regualtors that are inherited by micromeres 

34

Pmar1 genee

repressed HesC, which is also a repressor. Activated by Otx and B-catenin, which are concentrated in vegetal pole of egg cell.

35

molecules involved in double-negaive gated micruit for micromere specification

Otx, B-catenin, Pmar1, HesC, genes Alx1, Thr, Etx, Delta

36

HesC

repressor of genes involved in mircomere specification: Alx1, Thr, Ets, Delta

prevents formation of skeletoal mesenchyme cells  in micromeres

37

double-negative gated circuit in veg2 cell

In veg2, this circuit is broken because Pmar1 not activated, so HesC represses skeletogenic genes 

38

Skeletogenic mesenchyme cells

  • cells specified to autonomously ingress into blastocoal and become skeleton of sea urchin
  • also induce neighbors to become endoderm and non-skeletogenic mesenchyme cells (pigment; coelom cells)

39

Dishevled and B-catenin

found in cytoplasm, inherited by micromeres at fourth celavage. these are the initial regulatory inputs for micromeres

40

Disheveled

prevents degradation of B-Catenin in micromeres and macromeres. it is located in the vegetal cortex

41

B-catenin role in cleavage

  • specifies micromeres. accumulates in cells fated to be endoderm and mesoderm and causes them to develop autonomously. 
  • Specifies the vegetal half of the egg

42

Blimp1 and Wnt 8

form a positive feedback loop to make more B-catenin. Blimp1 is also activated by Otx adn maternal B-catenin

43

ES (early signal)

  • inducing signal of micromeres that is controlled by Pmar1 and HesC
  • instructs other cells to be endo/mesoderm and can also establsh second axis when micromeres are transplanted to animal region of the embryo

44

Notch 

a protein that tells cells below it to become nonskeletal mesenchyme cells. activates by Delta juxtacrine protein

45

Differentiation of cells in micromeres

become skeletogenic because of early signal and delta proteins in double-negative gated channel of Pmar1 and HesC

46

commitment

cell fate resulting in differentiation

47

specification

differentiation when cells are in neutral environment. this type of commitment is reversible, so it is not a true commitment

48

determination

type of cell developmental commitment that results in autonomous differentiation. This means the cells will differentiate even in a nonneutral environment. Irreversible

49

Two types of cell developmental commitment

specification and determination

50

two types of cell specification

autonomous and conditional specification

51

autonomous specification

cytoplasm no homogeneous, but instead contains different inheritants and derterminants 

However, cells know their fate and become determined without interaction from other cells 

micromere cells are this 

52

conditional specification

cells achieve respective fates by interacting with other cells

they are specified by paracrine factors secreted by neighbors 

53

cleavage of sea urchin animal half/pole

  • 4th cleavage is meridional
  • 5th cleavage is equatorial and forms animal 1 and 2 layers
  • 6th cleavage is meridional
  • all of these cleavages are equal, meaning cells are same volume

54

cleavage of sea urchin vegetal half/pole

4rth cleavage is equatorial and uneven, forming 4 macromeres and 4 micromeres

5th cleavage, macromeres divide meridionally to form 8 cells; micromeres divide equatorially 

6th cleavage is equatorial and even for all

55

fate of animal half of sea urchin egg

becomes epithalium and neurons. so skin and neurons

56

1st vegetal half fate in sea urchins

becomes ectoderm (top half) and endoderm (bottom half)

57

2nd vegetal half fate in sea urchins

becomes coelom, non-skeletogenic mesenchyme - muscles, pigment - and endoderm 

58

so what do large micromeres become?

skeletal mesenchyme 

59

What is the first gastrulation event?

ingression

60

gurken

  • gene in drosophila, made in nurse cells, gets transpirted to oocyte nucleus and translated to protein.
  • serves to anchor nanos mRNA to posterior end of embryo

61

Par1

in drosophila, organizes microtubules with (-) cap and (+) growing ends to anterior and posterior ends of oocyte

62

Kinesin

motor protein ATPase that sends molecules to (+) posteror end of drosophila embryo. moves Oskar mRNA and nanos 

63

Oksar

an mRNA in drosophila transported by kinesin to (+) posterior end of the embryo

64

Dynein

in drosophila, a motor protein that transports mRNA to anterior (-) end of embryo

transpors bicoid

65

Bicoid

  • mRNA in drosophila that goes to anterior (-) end of embryo
  • causes formation of acron (most anterior end), head, and thorax. Without it the mutant has two tails (Telson)

66

Torpedo

  • Gurken receptor on posterior end of drosophila embryo
  • Inhibits expression of Pipe gene
  • causes follicle cells to differentiate to dorsal morphology

67

Pipe

gene in drosophila that activated Nudel and is only found in ventral follicle cells. 

68

Nudel

activated by Pipe in drosophila. activates 3 serine proteases: gastrulation defective (gd), snake, and easter genes 

69

What happens after Nudel is activated in drosophila?

  • Nudel and factor x split gd protein
  • Gd splits snake protein
  • Snake protein cleaves Easter protein
  • Easter splits Spatzle
  • Spatzle binds to Toll receptor protein

70

Toll

  • receptor protein activated by binding of Spatzle 
  • activates Tube and Pelle

71

Tube and Pelle

activated by Toll

phosphorylate Cactus protein. Cactus is degraded and released from Dorsal protein

72

Dorsal 

protein separated from Cactus when Cactus is degraded after being phosphorylated by Tube and Pelle

Dorsal protein enters nucleus and ventralizes the cell

73

molecules involved in ventralizing follicle cells in drosophila

Pipe, Nudel, Gd, Snake, Easter, Spatzle, Toll, Tube, Pelle, Cactus, Dorsal

74

Cactus

protein that is phosphorylated by Tuve and Pelle, causing release of dorsal protein into cell neuclus to ventralize it

75

2 major types of cells in an embryo

epithelial cells and mesenchymal cells

76

epithelial cells

tightly connected to one another in sheets or tubes

77

mesenchymal cells

unconnected to one another and operate as independent units 

78

Ectoderm

becomes nervous system, skin, eyes, inner ear 

79

mesoderm

becomes muscles, skeleton, and circulatory system, which includes kidneys, and gonads

80

Endoderm

digestive system and respiratory tract 

81

invagination

infolding of cell sheet to form a cavity

82

ingression

migration of individual cells to center of embryo

83

3 crucial axes of embryo

  • anterior/posterior
  • dorsal/ventral
  • right/left

84

blastocoel

hollow sphere of cells with central cavity. 

85

tight junctions

connect the blastomeres into an epithelial sheet

86

blastula

  • 1 cell-layer thick, adhered to hyalin layer
  • all cells eventually become the same size, because micromeres slow their division while others catch up

87

cells furthest from blastocoel 

become ciliated 

88

meridional cleavage

vertical cleavage of cells 

89

equatorial cleavage

horizontal cleavage of cells 

90

Cleavage characteristics of sea urchin 

isolecithal, radial holoblastic, fast and synchronous (because little yolk), size of blastomeres identical through 3rd cleavage, then different

91

why/how does biphasic cell cycle occur

because cyclin doesn't have to be transcribed. instead, cell cycle is using stored machinery. Division slows when run out of mRNA for cyclin and need to transcribe more cyclin gene

92

mid-blastula transition

when synchrony of biphasic cell cycle is gone and the embryo has to undergo further development

93

3 objectives of gastrulation

  1. Generates 3 germ layers
  2. bilateral symmetry
  3. establishes new and unique cel interactions which influence future developmental events

94

95

basal lamina

what fibronectin, lamain, collagen, and ellastin cells must bind to

96

cadherins role

family of cell-to-cel adhesion molecules that hold cells of blastula togehter as a sheet 

97

what 3 factors allow cells to move in embryo

concentration of matrix, orientation of matrix, and contact guidance

98

gastrulation: which movement happens first?

ingression first, then invagination

99

how does invagination happen?

inner halin membrane swells from absorbing water and pulls vegetal plate inwards as outer part constricts

100

aboral

side of embryo away from the mouth

101

when does pattern formation start in drosophila

super early, while egg still undergoing ovulation. so before second meiotic division

102

what is pattern formation

specialization and organization of phenotypes in flies, looking at multiple axes 

103

mRNA for which drosophila patterning proteins are evenly distributed?

for caudal and hunchback

104

Caudal 

protein in drosophila around posterior end 

105

Hunchback

drosophila protein found in anterior end 

106

bicoid vs. caudal

bicoid protein blocks caudal mRNA from becoming caudal protein

107

nanos and hunchback

nanos protein blocks hunchback mRNA from forming hunchback protein 

108