neural crest cell maturation vs. specific cell type differentiation

[David Hill]

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?

David


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!)
>
> -Doug
>
>
> 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.
>>
>> David
>>
>>
>>
>>
>>
>>
>> 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
>>
>>
>>
>>


-- 
David P. Hill, Ph.D.
Senior Scientific Curator
Mouse Genome Informatics
Gene Ontology Consortium
The Jackson Laboratory
600 Main Street
Bar Harbor, ME 04609-1500
tel:207-288-6430
htpp://www.informatics.jax.org
http://www.geneontology.org