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neural crest cell maturation vs. specific cell type differentiation
dhowe at cs.uoregon.edu
Thu Mar 16 13:01:12 PST 2006
Good by me...
David Hill wrote:
> The maturation term was instantiated for cases where looking at a cell
> morphologically it doesn't look like it is doing anything, but it is
> in fact synthesizing gene products to make it totally functional. One
> example of this (sorry it is not neural crest) is the epithelial cells
> of the intestinal crypts. They are born at the bottom of the crypts as
> columnar epithelial cells, the process making them conform to this
> shape would be their morphogenesis. As they mature, they don't change
> shape, but they move up along the villus due to the death of the cells
> at the tip and the birth of new cells at the bottom. While they are
> moving up, they are synthesizing the gene products that make them
> functional absorbative cells. This would be part of their maturation.
> Eventually they apoptose. This would also be part of their maturation.
> The idea was to capture the processes that were involved in a cell
> becoming "an adult" that weren't directly related to the changes in
> shape of the cell. Another example would be a neuron that has fully
> extended its axons and dendrites and then receives signals about what
> kind of receptors and neurotransmitters it is going to make. This
> would be maturation because it doesn't have anything to do with
> creating the shape of the cell.
> Does this make sense?
> Doug howe wrote:
>> Well stated David!
>> The thing that I'm still not clear on then is what the "X cell
>> maturation" terms are representing.
>> X cell maturation would be defined as :
>> The process leading to the attainment of the full functional capacity
>> of an X cell. This process is independent of morphogenetic change.
>> While X cell development would be defined as:
>> The process aimed at the progression of a y cell over time, from
>> initial commitment of the cell to a specific fate, to the fully
>> functional differentiated cell.
>> Can you clarify the distinction...maybe using neural crest cells as
>> an example? (sounds like a thesis defense question!)
>> David Hill wrote:
>>> In general derivatives are considered as separate cell types. So,
>>> when a neural crest cell migrates to where it is going and it is
>>> receiving signals about what it is going to become, it is being
>>> committed to become another cell type. This process, as GO defines
>>> it, is part of the differentiation of that other cell type, not part
>>> of the maturation of the neural crest cell. Although the line
>>> between when one cell begins and another ends is fuzzy, if we start
>>> to try to represent cell lineages in the process ontology, we run
>>> into huge issues. The most obvious ones are things like "Is the
>>> differentiation of a pigment cell part of the development of a
>>> neural crest cell because it happens to the neural crest cell, or
>>> is the development of a neural crest cell part of the
>>> differentiation of a pigment cell because it needs to happen for the
>>> pigment cell to differentiate. For this reason, we keep the lineage
>>> relationships out of the ontology. The lineage relationships are
>>> captured in the cell type ontology. At some point, we can use the
>>> two ontologies to derive both the processes and the lineages. So,
>>> for example, if a pigement cell develops only from a neural crest
>>> cell in the cell ontology, then we can define the process of pigment
>>> cell fate commitment as the process by which a neural crest cell
>>> becomes committed to form a pigment cell.
>>> Melissa Haendel wrote:
>>>> Hi, I wanted to send this set of questions separately than my
>>>> previous email as I think they will require discussion.
>>>> I need a term that represents the final stages of neural crest cell
>>>> differentiation into their derivatives. I could annotate to
>>>> pigment cell differentiation, etc, but it would be better to say
>>>> that all derivatives don't begin their differentiation. Once
>>>> neural crest cells begin to differentiate into their derivatives,
>>>> they are no longer called neural crest cells. So, would the term
>>>> "neural crest cell maturation' with the following definition work?
>>>> "The process leading to the attainment of the full functional
>>>> capacity of a neural crest cell derivative. This process is
>>>> independent of morphogenetic change." I have added the word
>>>> derivative, but I don't know if this will fly. Thought I would
>>>> email the listserve for advice before making a request.
>>>> How have any of you dealt with differentiation into derivative cell
>>>> types with different names in the past?
>>>> Any advice is much appreciated.
>>>> Thanks, Melissa Haendel
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