L6 Drosophila, Neurogenesis (Imported from Quizlet)

Neurogenic region is established _______ with low level of _______ _____ protein

Ventrolaterally, nuclear dorsal

What are extremely important cells in organisms for controlling its response to internal and external cues with sub second speed?

Neurons

The process is very _______ or _______ with vertebrate neurogenesis, applying genetic methods in this organism (drosophila) has given detailed molecular understanding of their formation

Homologous, analogous

The domain from which they neurons are formed is a _______ ______ defined by the gene _____ where there is a lower level of _____ ______

Ventrolateral domain, rhomboid, nuclear dorsal

When the mesoderm invaginates to form internal structure of the embryo, what does the neuroectoderm do?

Comes to lie ventrally which gives rise to neurons

Where does the neural tube form in vertebrates?

On the dorsal side

The dorsoventral (D/V) axis may be inverted in arthropods and vertebrates (True or False)

True

What does BMP stand for?

Bone morphogenetic protein

What does DPP signal stand for?

Decapentaplegic signal

What is BMP/DPP important for?

Patterning dorsal in drosophila, patterning ventral in vertebrates

In the idealised arthropod what was developed and where?

A circulatory system developed at the dorsal side where the nerve chord was located ventrally

In the idealised vertebrate it was the opposite, the heart and the vascular system derived from a ______ position whereas the brain and nerve chord _____ ________

Ventral, form ventrally

The idea of inversion is also now confirmed molecularly, how?

There is a signal that helps to set up the D/V axis that is conserved

BMP in _______ and DPP in _____ are essentially the same molecule

Vertebrates, flies

In flies, high levels of BMP define ______, in vertebrates BMPs define ______

Dorsal, ventral

Within the neural region the "flipping over" seems to work well

Different domains in the neural region can be defined by expression of genes in a precise bilateral pattern and at the middle and ind and msh more laterally

Not all cells in the fly neuroectoderm will become neurons, what happens to the others?

Some will remain ectodermal

Single neuronal cells are selected from a group of almost equivalent cells known as ...?

A proneural cluster

This process uses a highly important patterning mechanisms that will also be found in mice and humans known as _______ _______

Lateral inhibition

What set up the proneural genes?

Achaete/scute genes

What does notch/delta signalling pathway ensure?

Selection of a single cell out of the cluster

Within this cluster a section process is initiated using a ___-__-___ _____ pathway known as the ____/_____ pathway

Cell-to-cell signalling, notch/delta

Achaete/scute proteins promote which expression?

Delta

Delta is a _______ ______ (stuck in the membrane), it can only influence ________ cells

Transmembrane ligand, neighbouring

Delta binds and activates _____ receptor, there will be small differences in delta expression, the proneural genes promote _____ expression

Notch, delta

A strong notch signal will _______ achaete/scute genes, as a result the small difference in achaete/scute expression will become ______ so ____ will be expressed in the top cell and _____ in the bottom cell

Downregulate, amplified, more, less

High and continuous achaete/scute expression activates ______ _____, the "losing" cell reverts to epidermal fate since it has stopped expressing achaete/scute

Neural genes

_ proneural clusters per segment, most clusters are already single cells

8

What is Vsx1?

A gene that is important for the formation of a particular type or interneuron

What is happening in this image?

Zebrafish embryo, stained for Vsx1

One is wild type, the other two have the notch signal blocked or activated

What happens after selection of a neuroblast?

It will generate a number of neuronal and glial cells, in a stereotypic manner

What can glial cells be considered as?

Neuronal support cells

The process of selecting a neuroblast also happens in various different tissues and organisms known as ________ ____ _________

Asymmetric cell division

Like lateral inhibition, selection of a neuroblast is a ______ _______ _______

Basic developmental principle

After selection of the neuroblast, that cell will drop down from the _______ into the ______ of the embryo

Epithelium, interior

All cells in the drosophila epidermis have an inherent polarity, apico-basal polarity neuroblasts do what in regards to their apico-basal polarity?

Remember it

When the neuroblast has been selected via ______ _____ the cell will drop down from the _____ into the _____ of the embryo

Lateral inhibition, lumen, interior

All cells of the drosophila epidermis have an inherent polarity and know what is inside and outside, how is this determined?

Different proteins associated with the membrane that is in contact with the outside as compared to the inside

What does the drosophila cell "memory" consist of what?

A localised protein complex, Bazooka (Par3 in mammals) is part of this

The protein complex within "memory" directs the localisation of proteins and certain RNAs on the opposite side of the cell, what is also an important part of this?

"Numb"

The protein complex within "memory" also does what?

Orientates the mitotic spindle which determines the plane of division

What does the orientation of the mitotic spindle result in?

Two cells are formed that are different

What are the two cells that have been formed and what do they do?

One is a neuroblast that will act like a stem cell and will continue to make differencing cells, the other that received the complex containing numb will become a ganglion mother cell (GMC)

In the cortex of a developing mouse, neural stem cells have an unusual _____ shape, spanning the ______ ______ layer

Elongated, entire neural

In the embryonic cortex, just before cell division the nucleus of these cells move _______ -> so the "inside" surface of the _____ next to the _____ ______

Inwards, brain, brain ventricle

In the embryonic cortex, it is known that the division is _______ to form a differentiated neuron ____, localisation is towards the ____ ____, same in drosophila

Asymmetric, Par3, stem cell