dendrite outgrowth and patterning Flashcards
what is a dendrite
branched projections of a neuron that act to propagate the electrochemical stimulation received from other neural cells to the cell body or soma from which the dendrites project.
are dendrites diverse?
Yes. they are very diverse.
where are dendrites targeted?
they are targeted to specific nuclei, where they synapse with axons
how do the secretory and endocytic systems affect dendrite outgrowth and patterning
allow coordinated secretion of cellular components to control dendritic outgrowth and arborization
how do microtubule-based polarized trafficking of vesicles affect dendrites outgrowth and branching
transport a substantial amount of proteins and lipid to the distal dendrites.
self-avoidance
branches from the same neuron recognize and repel each other, leading to branch separation and/or even spreading across the territory
what does self-avoidance ensure?
orderly projection of sensory and synaptic inputs for efficient and unambiguous signal processing
tiling
complete but non-overlapping coverage of a receptive field by arbors of a functionally related group of neurons
what does tiling do?
allows neurons of the same class to cover entire dendritic field completely and non-redundantly
heteroneural overlapping
dendrites from different types of neurons share overlapping dendritic fields.
what does heteroneural overlapping do/
allows different neuronal types to process different sensory or synaptic inputs in the dendritic field.
how do isoneuronal dendrites know not to make contact
this is a contact-depedent repulsion mechanism based on DsCam molecules
what are DsCams?
they are a family of cell adhesion molecules that mediates contact-dependent isoneuronal repulsion through gene-splicing. they are required for self-avoidance in dendrites.
what mediates self-avoidance in mammals
protocadherins
is Dscam required for tiling?
no.
what mediates tiling?
Tricorned kinase (TRC) and Furry (FRY)
what is abrupt?
BTB-Zinc finger protein that suppresses dendritic complexity. only expressed on class I da neurons
what does cut do?
expressed in da neurons. increases the complexity of arbors.
what does knot do?
expressed in IV da neurons. increases complexity of arbor. increases the complexity in class I and II
how do neurons acquire type specific dendritic arbors?
by combinatorial expression of different mediators of arborization
what are the possible ways for dendrites targeting?
dendrites first, axons first or both at same time.
how are dendrites targeted?
they reach the nuclei first, the axons infiltrate.
what molecules are expressed for matching axons and dendrties
teneurins
what else mediates dendritic arbor formation and localization
semaphorin gradients in the nuclei, properly orient dendrits.
what mechanisms regulate dendrite targeting
intrinsic factors (TF) pre-specify targeting. interactions between pre and post synaptic partners as well
what is involved in the process of dendrite development and morphogenesis
outgrowth and branching self-avoidance and tiling diversity and complexity guidance and targeting scaling remodeling activity-dependent regulation
