Imagine that you stably transfected a small group of cells at the margin of the posterior neural plate as indicated in the figure. You transfected the cells with a constitutively expressed reporter gene such as green fluorescent protein (GFP). All cells generated by the division of the transfected cells would express GFP. Thus, you can follow the lineage of the cells that you originally transfected. What cell type(s) in the adult would you expect to express GFP and where would you expect to find them?
lineage tracing
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By my rough judgement, that area of the neural plate looks to be located caudally or anterior to the section that will form early brain vesicles. This would allow me to deduce the position of the cell bodies of the neurons expressing GFP in an adult to be in or near the spinal cord.
Additionally, the lateral position of the transfected cells allows me to deduce that they would occur in the neural crest or the dorsal region of the neural tube.
I would conclude that the cells expressing GFP would either be found in the dorsal root ganglion or in the left dorsal horn of the spinal cord.
I would like to add that I'm more confident that GFP would be expressed in the dorsal root ganglion.
I agree that the transfection site appears to be on the narrower part of the neural plate, which would give rise to spinal cord. I would also agree that after the neural tube forms, the transfected site would be found either in the dorsal region of the neural tube or the neural crest. I assume from this picture that the transfection site is on the very edge of what will fold up and fuse to form the neural tube, so I think it is very likely that these cells would be found at the dorsal region of the neural tube that eventually delaminates from the tube to from the neural crest.
I know that the neural crest can give rise to several different cell types (dorsal root ganglia, autonomic ganglia, etc). What made you say that the GFP expressing cells in this case would go on to form dorsal root ganglia specifically?
I would like to note that it does not state at what depth it transfects the cells, just that it was transfected in that region. So if it was transfected at the surface, it thus would depend on where neural plate turns into pre-neural crest cells and how deep the transfection was. As it states "at the margin of the posterior neural plate", this could mean the pre-neural crest cells or it could simply mean that it is still neural crest cells. These in turn, form dorsal neural cells in the spinal cord (sensory neurons) and/or (could transfect both if on the margin of neural crest and neural plate cells) autonomic ganglia, dorsal root ganglia and/or melanocytes for the thoraxic-lumbar region of the spinal cord and around that area. If it is transfected a little lower than the ectoderm, then these could give rise to skeletal bones or muscles.
Through the process of neurulation, the transfected area will go from being lateral on the neural plate to dorsal on the neural tube. Due to its position at the margin of the posterior neural plate, the transfected area will be part of the middle portion of the plate that will fold first. The transfected area will be at the dorsal most region of the tube. It is at the edge of the neural plate and when it joins with the other lateral edge of the plate, the transfection site will make up a portion of the neural crest. The crest will migrate away from the neural tube and differentiate into a variety of cells. The variety of cells include muscle, neurons, glia, etc... These cells can be found in the peripheral nervous system.