Cell type identity and neuronal diversification Flashcards
Do neurons with the same morphology carry the same functions?
Likely, but not necessarily.
What are potential definitions of neuronal cell types?
Populations of neurons homogenous in properties that different them from other neurons. Central properties are their function, morphology, physiology, and genetic (molecular) basis.
Is it useful to map each neuron individually? What is an alternative? What is tricky about the alternative?
It can be, like in the case of C. Elegans. But in more complex organisms like humans, the task is for now pointless to carry.
The alternative can be to categorize neurons in groups and characterizing those populations instead. The tricky part is to coherently and logically define those groups.
How do microfluidics and high-throughput single- cell qPCR relate?
Single-Cell Isolation:
Microfluidic arrays can be designed to isolate single cells efficiently, allowing for the precise handling of individual cells in high-throughput experiments.
Sequential Processing:
Microfluidic devices can be used to sequentially process single cells for reverse transcription and subsequent qPCR reactions, providing a streamlined workflow for high-throughput single-cell analysis.
What is FACS? What do cells need to express in order to be sorted by FACS?
Florescence-activated cell sorting (FACS) requires that proteins of interest are fused to fluorescent reporters, which will allow for the laser to generate a fluorescent scattering signal.
True or false: single dopamine neuron types are typically found in distinct neuroanatomical regions
False: multiple.
Who first reported the diversity of neurons? With what technique?
Cajal with Golgi staining (silver staining).
What is single-cell transcriptomics? What are its advantages?
Molecular methods that allow to simultaneously quantify the mRNA levels of thousand of genes in a single cell from a cell population of interest
High-throughput (simultaneously measure a huge amount of genes at a low cost)
Refines cell population taxonomy (identify markers)
Reflect cellular function
Clinically relevant: link GWAS to specific cell populations
What are the functional components of the neuron that allow its classification on the connectivity, input, and output levels?
Connectivity: cell adhesion molecules
Input: receptors, signalling, ion channels
Output: signalling, ion channels, synaptic release
Can the expression profiles of cells inform about their function?
That’s the consensus.
Single-cell transcriptomics arose from developments in two fields. What are they?
Sequencing technology
Microfluidics
What is the fundamental output difference between Sanger sequencing and Next-Generation Sequencing?
Sanger = obtain sequencing and quantification information for a single DNA sequence
NGS = obtain sequencing and quantification information for millions of DNA sequences
What are the main steps in NGS? Sanger sequencing?
NGS
1. DNA fragmentation
2. In vitro adaptor ligation
3. Generation of polony array (DNA fragment clusters)
4. Cyclic array sequencing
Sanger
1. DNA fragmentation
2. In vivo cloning amplification
3. Cycle sequencing (DNA polymerase, dNTPs, ddNTPs)
4. Capillary electrophoresis
What is droplet-based cell isolation? To which field does that technology belong?
Doplet-based cell isolation is a technique by which a single cell can be engulfed in an oil drop, allowing its isolation from other cells
What are UMIs?
Unique molecular identifiers: Unique short sequences or molecular “tags” added to DNA fragments in some next generation sequencing library preparation protocols to identify the input DNA molecule. These tags are added before PCR amplification, and can be used to reduce errors and quantitative bias introduced by the amplification.
