myelin sheath & Schwann cells

[gocentral]

From Sebastian K. This is causing problems with HPO inference, as we end up with the assumption that myelin is always in the PNS:

[Term]
id: GO:0043209
name: myelin sheath
namespace: cellular_component
def: "An electrically insulating fatty layer that surrounds the axons of many neurons. It is an outgrowth of glial cells: Schwann cells supply the myelin for peripheral neurons while oligodendrocytes supply it to those of the central nervous system." [GOC:jl, NIF_Subcellular:sao-593830697, Wikipedia:Myelin]
synonym: "astrocyte sheath" NARROW [NIF_Subcellular:nlx_subcell_20090204]
synonym: "oligodendrocyte myelin sheath" NARROW [NIF_Subcellular:sao1279474730]
synonym: "Schwann cell myelin sheath" NARROW []
xref: FMA:62983
xref: NIF_Subcellular:sao-593830697
xref: Wikipedia:Myelin
is_a: GO:0044464 ! cell part
***relationship: part_of CL:0000218 ! myelinating Schwann cell

Weaken to 'glial cell'? Introduce two subtypes (oligodend, Schwann)?

To complicate the issue further, some arthropods have 'myelin'; but I think the proposed weakening works for these too.

Reported by: cmungall

Original Ticket: geneontology/ontology-requests/11392

[gocentral]

Here is the explanation we get - I think it's the GO derived axioms that are at fault

Original comment by: cmungall

[gocentral]

The Schwanns and oligodendrocytes are referred to collectively as "myelinating glial cells" to distinguish them from other types of glia which are non-myelinating. 'Myelin sheath' should be a part of "myelinating glial cell".

Doug

Original comment by: doughowe

[gocentral]

We have CL:0000328 ! myelin accumulating cell (undefined in CL, inherited from initial version of CL).

This includes 'myelinating Schwann cell', but not oligodendrocyte.

Anyway, I think this class is weird, and should be obsoleted with a consider to CL:new 'myelinating glial cells'

For now, I think we should just generalize the GO axiom to 'glial cell'

CL also makes a distinction between plain Schwann cell and 'myelinating Schwann cell'. Do we need the latter?

         is_a CL:0002573 ! Schwann cell [DEF: "A glial cell that ensheathes axons of neuron in the peripheral nervous system and are necessary for their maintainance and function."]
          is_a CL:0000218 ! myelinating Schwann cell ***  [DEF: "A neuroglial cell of the peripheral nervous system which forms the insulating myelin sheaths of peripheral axons."]

Original comment by: cmungall

[gocentral]

Also of relevance: https://github.com/obophenotype/uberon/issues/628

Original comment by: cmungall

[gocentral]

https://code.google.com/p/cell-ontology/issues/detail?id=161

Original comment by: cmungall

[gocentral]

Weakened link: ‘myelin sheath’ part_of ‘glial cell’ rather than ‘myelinating Schwann cell’. Closing as I see that the other issues are reported in separate trackers. BTW I love the current parent of CL:0000328 ! myelin accumulating cell... 'stuff accumulating cell' :-)

Thanks, Paola

Original comment by: paolaroncaglia

[gocentral]

• labels: --> Other term-related request, neurobiology
• status: open --> closed-fixed

Original comment by: paolaroncaglia

[gocentral]

Just a quick comment in response to Chris' question above:

"CL also makes a distinction between plain Schwann cell and 'myelinating Schwann cell'. Do we need the latter?"

There are myelinating and non-myelinating Schwann cells and oligodendrocytes. They each derive from a common pool of precursor cells for their specific glial cell..ie Schwann cells derive from a Schwann cell precursor pool and oligodendrocytes from and oligodendrocyte precursor pool.

So for CL, it makes sense to have

Schwann cell ---[i] myelinating Schwann cell ---[i] non-myelinating Schwann cell

Likewise for oligodendrocytes.

Eventually we want CL: myelinating glial cell (or myelin forming glial cell) ---[P] GO: myelin sheath ---[i] CL: myelinating Schwann cell ---[i] CL: myelinating oligodendrocyte

Original comment by: doughowe

[gocentral]

OK, so setting this ontology ticket to pending, waiting for the CL changes to be done. Then I will add the link GO myelin sheath part_of CL myelinating glial cell (or myelin forming glial cell). Thanks

Paola

Original comment by: paolaroncaglia

[gocentral]

• labels: Other term-related request, neurobiology --> Other term-related request, neurobiology, cell type
• status: closed-fixed --> pending-accepted

Original comment by: paolaroncaglia

[gocentral]

Hi Chris and Doug,

Just following up on this, wondering if the changes in CL have been completed. Otherwise, is there a CL ticket I may refer to?

Thanks,

Paola

Original comment by: paolaroncaglia

[paolaroncaglia]

@cmungall Hi Chris, any updates on this please? (Doug doesn't seem to have a github account) Thanks, Paola

[cmungall]

I can grant access to CL for anyone that needs it

[paolaroncaglia]

Hi @doughowe and @cmungall

I’m closing this ticket because nothing else can be done in GO at this stage (and we’ve fixed GO as far as we could go). The ball is in CL’s park now. If you wish, could one of you please open a ticket in the CL tracker to request the changes listed by Doug in his comment dated Dec 12, 2014.

Thanks!