​​​​『BICCN Column』The establishment of Nature genetic tools-motor neuron cortical glutamatergic neuron-specific strains

Written | November https:// column | General: Cerebral cortex motor neuron map landscape and database alliance BICCN; "BICCN column" Nature | Mouse brain single cell DNA methylation map; "BICCN column" Nature | Human neocortex expansion and glutamatergic neuron diversification; "BICCN column" Nature | | Mouse cortex-basal ganglia-thalamic network Working model; "BICCN Column" Nature | Peng Hanchuan/Zeng Hongkui and other reporters define the morphological diversity of single neurons in cell types October 6, 2021, as a landscape of cerebral cortex motor neuron maps and one of the database alliance BICCN cold springs in the United States The Hong Kong Laboratory’s Z.
Josh Huang research group published an article titled Genetic dissection of the glutamatergic neuron system in cerebral cortex.
Through the establishment of a series of driving strains, the glutamatergic neuron system in the motor neuron cortex was finely located and identified.
, And provides an important tool for further research on disease models
.

Different types of glutamatergic vertebral neurons mediate the inflow and output of information processing in the cerebral cortex, but most of these cells come from neural precursor cells in the embryonic dorsal telebrain [1]
.

Neural precursor cells differentiate to form radial glial progenitors (RGs), which undergo asymmetric division to produce different subgroups of glutamatergic vertebral neurons, and migrate to the motor neuron cortex in order from the inside to the outside (Picture 1) [2]
.

To classify the cell subpopulations of vertebral neurons based on developmental and molecular biology procedures, a series of genetic strategies and tools need to be established
.

Single-cell transcriptome analysis shows that there are more than 50 types of glutamatergic vertebral neurons, but the genetic tools currently used for glutamatergic vertebral neurons are still limited
.

Figure 1 The main classification of glutamatergic vertebral neuron projections.
To this end, the authors hope that by establishing a genetic toolbox for glutamatergic vertebral neurons and revealing their developmental procedures, these genetic tools can The differentiation of different cell types and specialized gene expression patterns are explored, so as to establish different cell subgroups and development trajectories with biological significance, and to clarify the organization and assembly process of cell subgroups in the brain motor neuron circuit
.

In order to achieve this goal, the authors must first locate and define the precursor cells of glutamate vertebral neurons
.

The transcription factors LHX2 and FEZF2 will play a key role in the formation of cortical neurons [3,4], but the differentiation potential of Lhx2+radial glial progenitor cells and Fezf2+radial glial progenitor cells is still unclear.
Clear
.

To this end, the authors constructed mouse strains of Lhx2-CreER, Fezf2-CreER and Fezf2-Flp, so that a series of cell fate identification experiments can be carried out (Figure 2)
.

In the embryonic stage, pulse tracking experiments proved the differentiation potential of early radial glial precursor cells, and also proved the pluripotency of Lhx2+ radial glial progenitor cells at these stages
.

Through the expression of the two transcription factors, the authors identified three radial glial precursor cell subgroups (Figure 2), which laid a good foundation for the subsequent classification of glutamatergic vertebral neurons
.

Figure 2 LHX2 and FEZF2 transcription factor line cell fate identification patterns and different expression patterns.
Early cortical precursor cells include two subgroups of proliferation and neurogenicity.
Using a similar strategy as previously mentioned, the authors will express their expression in Gu The co-regulatory factor Tis215 expressed in the aminergic and gamma-aminobutyric acid neurogenic radial glial precursor cells was constructed as a driving strain, so that this strain can be used to define neurogenic radial glial cells
.

These precursor cell strains help to dissect the diversity of glutamatergic vertebral neuron ancestors, so that the origin of the vertebral neuron lineage and the development trajectory of neural circuit organization can be traced
.

As a result, the authors have built a series of more specific strains for the key driving genes of glutamatergic vertebral neurotransmutation subpopulations, which can treat a single cell as a small group of cells under the induction of tamoxifen.
Control and dose-dependent labeling and genetic manipulation (Figure 3)
.

In order to further analyze the subgroups of vertebral neurons defined by the driving line, the authors introduced the retrograde tracing technology
.

Through retroAAV and fluorescent gold particle injection, the specificity of the label in the specific driver strain can be determined
.

In order to further confirm the previous source of neuron projection, the authors introduced IS (Intersection-Substraction) reporting factor system 6, which proved the projection location consistent with previous research
.

These driver strains in different regions can distinguish vertebral neurons of different anatomical regions and different birth dates with high accuracy
.

Figure 3 Genetically targeted strains for labeling different glutamatergic vertebral neuron subgroups.
In general, the authors constructed a series of glutamatergic vertebral neuron-driven strains in this work, which can provide a systematic analysis of glutamatergic vertebral neuron driver strains.
Satinergic vertebral neurons provide higher specificity, greater coverage, and better robustness, so that they can be classified more precisely, and the motor cortex can be classified in different developmental stages, different anatomical structures, and pathological conditions.
To locate the fate of neurons, it also provides an important mouse tool for a variety of studies
.

Original link: https://doi.
org/10.
1038/s41586-021-03955-9 Plate maker: 11 Reference 1 Huang, ZJ Toward a genetic dissection of cortical circuits in the mouse.
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