Midterm Flashcards
Nanos
Binds to 3’UTR of some mRNA and inhibits their translation
Polar granule component
Non-coding RNA that inhibits gene transcription by inhibiting rna pol II activation
Piwi
Acts with miRNA in an RNA silencing complex that’s inhibits translation by promoting degradation is specific mRNA
Vasa
RNA binding protein that functions as a translational initiation factor, promotes translation of mRNA coding for protein involved in pole cell differentiation
Oskar
Organizes pole plasm determinants to posterior end
Blimp1
Suppress somatic cell differentiation
Prdm14
Promote PGCs differentiation
Stem cell factor (SCF)
Signals PGCs to mitotically proliferate
Steel mutation
Mutation in gene coding for SCF
-no SCF being produced = PGCs don’t proliferate = infertile mouse
White spotting mutation
Mutation of gene coding for c-kit, the receptor for SCF
- same phenotype as steel
SDF-1
Gonads secrete this chemotactic protein that attracts PGCs
SDF-1 binds to its receptor CXCR4 on surface of PGCs
Pluripotency genes (OCT4, SOX2, NANOG) are expressed by
- ICM in mammal blastocyst
- Human embryonic stem cell
- Induced pluripotent stem cell (iPs cells)
Induced pluripotent stem cell
Cells that can be reprogrammed from somatic cell to become pluripotent
Diapedesis
In birds PGCs squeeze through extraembryonic blood vessels and get carried along bloodstream
Once they reach gonads, they squeeze out via diapedesis and will become either sperm or egg
Wnt4
Female gonads produce Wnt4 to direct PGCs to develop into diploid oogonia
Stra8
Mesonephros secretes RA
RA activates Stra8 expression
Stra8 triggers oogonia to enter meiotic prophase I
FGF9
Testis formation
Develop precursor cells (pre-spermatogonia)
CYP26B1
RA Is degraded by this enzyme
No RA signal -> no Stra8 expression -> cells remain pre-spermatogonia until puberty
Resact
Chemotatic peptide releases from jelly coat of AP sea urchin eggs
Resact diffuses from egg coat -> binds to receptor on sperm -> stimulates sperm flagellum -> provides sperm direction toward egg
Acrosome reaction
Triggered when sperm contacts polysaccharides in egg jelly coat
Exocytosis of its contents (proteolytic enzymes)
Acrosomal process formed
Bindins
Vitelline membrane binding proteins extend out (acrosomal process)
Sperm capacitation
Oviduct fluid changes sperm
Properties
-hyperactivity of sperm flagellum
-removes cholesterol from sperm plasma membrane
-unmasks zona pellucida binding proteins on Sperm head
- reduce affinity for oviduct walls to allow them
To swim through the oviduct to egg
Sperm attraction and guidance
1) thermotaxis - ampulla area warmer by 2 degrees
2) chemotaxis - progesterone and CRISP1 attract sperm to egg in ampulla
Hyaluronidase
Enables sperm to digest a path through cumulus cell layer
Izumo
Protein gets redistributed on outer surface of sperm head
Allows sperm head to bind to egg plasma membrane
ZP2 and ZP3
Helps sperm head bind/adhere to zone of pellucida
Contact and fuse with egg plasma membrane
Fertilization cone
Engulf sperm head in sea urchins
JUNO
Izumo protein on sperm binds to JUNO protein on egg = successful fertilization
CD9
Fusigenic protein
Promotes fusion of egg and sperm plasma membrane
Allows sperm nucleus to enter egg cytoplasm
Holoblastic cleavage
Isolecithal
Mesolecithal
Meroblastic cleavage
Teloecithal
Centrolecithal
Meridional plane
Cleaned along vegetal axis
South Pole to North Pole
When egg has lots of yolk - frog
Equatorial plane
Upper half is separated from vegetal lower half
West to east cleavage
Compaction
~16 stage cell
Individual blastomeres develop increased adhesive affinity to one another
Compacted together and develop tight junctions between them
E-cadherin
Increased levels of cadherin allows Blastomeres to bind together
It increases the adhesive affinity to one another
Trophoblast cells
Inactive hippo signal allows YAP to enter nucleus and activate Cdx2 expression which drivers outer cells to develop into trophoblasts and give rise to placenta
Cavitation
Blastocyst cavity develops
Na+ gets pumped in followed by influx of water -> tight junctions seal fluid in -> ICM moves to one side of cavity
Totipotent
Able to form both placenta and embryonic tissue
- early fertilization up to ~16 cell stage before cavity is formed
Pluripotent
Able to form all tissues of embryo but NOT placenta
-cavity is formed and 2 distinct cell populations
Unipotent
Only able to form placenta tissue
- single developmental fate
- trophoblasts
Multipotent
During gastrulation, ICM can give rise to 3 Derm layers
Blastoderm gives rise to 2 layers (like a pita bread)
Epiblast layer - gives rise to embryo
Hypoblast layer - does not give rise to embryo
Cellular blastoderm
-in drosophila, layer of individual cells surround the yolk
Actomyosin
Blocks gene transcription (aka no new mRNA synthesis)
Egg develops until blastula stage
Cycloheximide
Prevents translation of protein synthesis from mRNA
Cleavage blocked.
Maskin protein
Found in amphibian oocyte that blocks translation of a stored mRNA by binding 3’ to 5’ ends together
Major onset of new mRNA
Frog - mid-blastula (12th cleavage division)
Drosophila - cellular blastoderm (14th nuclear division)
Sea urchin - mid-blastula
Mouse - 8-16 cell morula
CLPG gene
Paternal copy
If mutated, causes enlarged rump in sheep
GCL Protein
Suppresses somatic cell differentiation and activates pole cells
-genomic inert hypothesis
