Neuronal lineage marker
A neuronal lineage marker can be either DNA, mRNA or RNA expressed in a cell of interest.
[6] Therefore, one of the most convenient methods for the rapid assessment of the expression of a cloned ion channel could be in situ hybridization histochemistry.
The study of the nervous system dates back to ancient Egypt but only in the ninetieth century it became more detailed.
With the invention of the microscope and a technique of staining developed by Camillo Golgi, it was possible to study individual neurons.
The reaction consists in fixing particles of silver chromate to the neurilemma, and resulted in a stark black deposit in the soma, axon and dendrites of the neuron.
[8] In 1887, a Spanish scientist called Santiago Ramon y Cajal learned the staining technique with Golgi and started his famous work of neuroanatomy.
He also described very precisely the purkinje cells, the chick cerebellum and the neuronal circuit of the rodent hippocampus.
In 1941 Dr. Albert Coons used for the first time a revolutionary technique that uses the principle of antibodies binding specifically to antigens in the tissues.
[12] This technique is called in situ Hybridization and it is used in a large variety of studies but mainly used in developmental biology.
By doing this hybridization we will be able to reveal the location of a specific mRNA, giving us information about the physiological process of organization, regulation and function of the genes.
[13] Some examples are the use of, digoxigenin- or fluorophore-conjugated oligo- nucleotide probes, for the detection of localized mRNAs in dendrites, spines, axons, and growth cones of cultured neurons; or digoxigenin-labeled RNA probes and fluorescence tyramide amplification for the detection of less abundant mRNAs localized to dendrites in vivo.
Immunohistochemistry is a technique that uses antibodies with fluorescent staining tags that target a specific antigen present in a certain protein.
An example of the application of this technique in neuroscience is the immunolabeling of antigens like NGF-Inducible Large External glycoprotein (NILE-GF), choline acetyltransferase, parvalbumin, and neurofilament protein.
[16] Immunocytochemistry uses the same method that immunohistochemistry, but with the difference that this technique is used in isolated cells in culture, and the other is in tissues.
They have two fundamental characteristics: they are self-renewing and upon terminal division and differentiation, they can give rise to the full range of cells classes within the relevant tissue.
[18] Cellular fates are analysed by staining with antibodies directed against antigens specific for astrocytes, oligodendrocytes, and neurons.
ALDH cells from embryonic rat and mouse CNS have been isolated and shown to have the ability to generate neurospheres, neurons, astrocytes and oligodendrocytes in vitro, as well as neurons in vivo when transplanted into the adult mouse cerebral cortex.
[18] Once a stem cell divides asymmetrically, the more mature progenitor is born and migrates to regions of differentiation.
As the progenitor migrates, it matures further until it reaches a site where it stops and either becomes quiescent or fully differentiates into a functioning cell.
Thus, as with other fields like haematopoiesis, a combination of positive and negative markers will be required to better define the central nervous system stem cell.
[20] In addition to intracellular molecules, products are available to study proteins which are expressed at the cell surface, including ABCG2, FGF R4, and Frizzled-9.
The differentiation of neural stem cells is controlled, in a context-dependent manner, by intrinsic factors and extracellular signalling molecules that act as positive or negative regulators that can be used as markers.
An oligodendroglial progenitor cell, for example, gives rise to oligodendrocytes until its mitotic capacity is exhausted.
[17] Some neural progenitor markers are capable of tracking cells as they undergo expansion and differentiation from rosettes to neurons.
Although functional studies of radial glia are increasing, it is difficult to distinguish them from neuroprogenitors and astrocytes.
Cytological markers that might be unique to radial glia include modified forms of nestin identified by the RC1 and RC2 antibodies that recognize the murine antigens.
[31] Neuronal lineage markers can be used in clinical research to identify diseased cells and/or in repair process.
Choline acetyltransferase (ChAT) is an enzyme responsible for catalyzing the synthesis of acetylcholine, and is expressed in the majority of cholinergic neurons.
[15] In motor regions, sensory cortex and in the basal forebrain these immunolabeling has been applied to evaluate disruptions in cholinergic neurons of the ChAT fiber network and also for overall morphology.
Nerve Growth Factor Rec/NGFR; Nestin; NeuroD; Neurofilament L 68 kDa; Neuron Specific Enolase/NSE; NeuN; Nkx-2.2/NK-2; Noggin; Pax-6;
