Early Development Lec02 Flashcards by brittany gouse

Gastrulation defines the ___, ___, and ___ axes of the nembryo

midline, anterior-posterior and dorsal-ventral

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the midline of the embryo is defined by the formation of the ____

notocord

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notocord is formation incudes the formation of the ____

neural ectoderm

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____ formationn is the ver y first event in neurogenesis

otochord formation

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___ are the neural rpecurosr cells, which turns into CNS

neural ectoderm

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if you treat ectoderm with ___ you get epidermis

bmp (a transforming growth factor beta)

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if you treat ectoderm with ___ you get NEUROECTODERM

noggin chordin (inhibit BMP)

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BMPs are made by the ____

surrounding tissue

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Factors that inhibit BMP signaling are produced by the ____ (

notochord

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___ signaling precedes BMP inhibition during neural induction

FGF

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what do noggin and chordin do?

block bmp (thus, inducing neural development)

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FGF stimulation increases production of ____

Noggin

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neural induction the lateral margins of the____ fold inward to form the \n\nneural tube

neural plate

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neural tube forms around day ___

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the____ pinches off when the NEURAL TUBE is formed

neural crest

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Neural tube closes from the middle both____ and ___

anteriorly and posteriorly (like a zipper going in both directions)

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____ vitamins in the first few weeks of \n\npregnancy decrease neural tube closure defects.

B-complex (folic acid)

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Spina Bifida rate in US is much lower since ____

nutrition

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Spina Bifida is the failure of the ____ end of the neural tube to close

posterior

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Anencephaly and holoprosenchephaly (Represents failure of the ___ neural tube to close.

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Anencephaly and holoprosenchephaly lack ___

forebrain

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____ makes cells in one area different from cells in another area

patterning

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ventral patterning is realted to ___ function

motor

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ventral siganl is secreted ____

sonic hedgehog

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dorsal siganl is secreted \_\_\_\_

tgf betas

sonic hedgehog eventually leads to differences in \_\_\_\_

trnascription

What produces dorsal ventral polarity?

high sonic hedgehog in notocord and roof plate no sonic headhog in the roof plate

roteins encoded by **hox genes** are powerful \_\_\_\_

transcriptional activators and repressors

results from abscence of sonic hedgehog:

1. The forebrain does not form 2. dorsal ventral polarity is disrupted

y dirsruptions in ____ also can cause cancers such as \n\nmedulloblastomas and basal cell carcinoma.

sonic hedgehog

Shh not only regulates polarity but \_\_\_

proliferation (disruptions in shh pathway can lead to different cancers)

cyclopy can be caused by abseence of \_\_\_

sonic hedge hog

when does anterior/posterior patterning occur? (relatively)

same time as neural induction and gastrulation (they all overlap)

spinal cord is from ___ patterning

anterior/posterior

rhomboencephalon is the future ___ and \_\_\_

pons and medulla

mesencephalon is the future \_\_\_

midbrain

diecepahlona nd telcephalon are part of the \_\_\_\_

prosencephalon

difference between fly and human hox genes\n

in humans they identify a specific segment along the anterior/posterior axis

Hox genes are involved in defining segmental differences in the \_\_\_, \_\_\_, and \_\_\_

spinal cord, \n\nmedulla and pons.

anterior/posterior patterning is accomplished through ___ genes

hox

there is no hox code for the ___ and \_\_\_

prosecenphalon and mesencephalon

OTX2 knockouts show complete loss of ____ polarity.

coordination of ___ and ___ regulates nervous system expansion

symmetrical and asymthetical proliferation

\_\_\_\_ is needed to organize distinct cell types into functional units

cell migration

\_\_\_ and \_\_\_\_s divide and differentiate in the ventricular zone

Neural stems cells and neural progenitor cell

multipotent stem cell either ___ or \_\_\_

neuronal or glial precurosr cells

\_\_\_ increases the size of the ventricular zone, which in turn increases the size nof the brain.

symmetrical divisons

pluripotrnt neural stem cells are capable of \_\_\_\_

self renewal

As development proceeds NSCs begin to divide asymmetrically giving rise to

one neural stem cell and one neuro precursor

Late in development NSCs will again divide symmetrically but give rise to two

neural pecursors (and therefore NSC disappear)

number of NSCs, progenitors, neurons and glia needs to be tightly controlled as \n\ndoes the timing of their generatio by ___ and \_\_\_

notch and bhlh transcription factor

notch ____ proneural gene

deactivates

if you remove the inhibition of proneural gene by notch in the neural stem cell ____ is upregulated

delta

what happens at low/moderate levels of Notch stimulation through Delta?

, the intracellular domain of Notch is cleaved and goes to the nucleus to activate bHLH genes. (cell is eventually primed to diff into a neuron)

bHLH activation also ___ Delta on neural stem cells cells.

upregulates

Notch gets hyper-activated (by delta after it is upregulated)--\>

shuts off **proneuronal bHLH genes** ----\> keeping cell in pluripotent nsc state

In this case astrogliogenesis differentiation from neural progenitors is ___ \n\ndependent

Notch

astrogliogenesis differentiation from neural progenitors is inhbiited by \_\_\_

bhlh genes

oligodendrocyte generation is induce

by other factors (Oligs and Nkx 2.1) (factor other than nox)

neurogenesis is finished by the \n\nmiddle of the ____ trimester.

second

Timing of gliogensis happens mostly

after birth

The basic shape of the brain is fully formed at birth and the vast majority of the \n\n\_\_\_\_ are already generated.

neurons

difference in brain after birth

dramatic increase in brain size, inc in myelin

primary neurlaiton is complete within the ___ weeks

first 3

most neurons in the cerebral cortex are produced between the ___ and ___ month of pregancy

first and 4th

f ectodermal pecursor cells are isolated and grown in a dish, they become \_\_\_\_

neurons (since there is no BMP present)

Stimulation of\_\_\_\_ factors induce **_neural stem cell formation._**

retinoic acid (RA), fibroblast growth factor (FGF) and insulin-like growth factor (IGF

what process are hox genes involved in?

posterior processing

how do hox genes create unique patterns of gene expression?

through repressing and enhancing each other

\_\_\_ promotes astrogliogensis

notch

\_\_\_ promotes oligodenrodensis

Olig1/2, Nkx 2.1

\_\_\_ inhibits Oligodendrogenesis

BHLH

\_\_\_ inhbiits Astrogliogenesis:

BHLH