What happens when oligodendrocytes are damaged?

What happens when oligodendrocytes are damaged?

Thus, neurotransmitter receptors play an important role in the normal life of oligodendrocytes. Furthermore, if oligodendrocytes become damaged and the myelin sheath is destroyed, the action potential is reduced in velocity or ceases altogether, leading to physical or mental disability.

How are oligodendrocytes formed?

Oligodendrocyte formation in the adult brain is associated with glial-restricted progenitor cells, known as oligodendrocyte progenitor cells (OPCs). SVZ cells migrate away from germinal zones to populate both developing white and gray matter, where they differentiate and mature into myelin-forming oligodendrocytes.

How can transcription factors cause cancer?

A mutation in the DNA of a promoter or enhancer region may increase the binding ability of a transcription factor, which may then lead to the increased transcription and anomalous gene expression that is seen in cancer cells.

What causes myelination?

Triggers. Demyelination is often caused by inflammation that attacks and destroys myelin. Inflammation can occur in response to an infection, or it can attack the body as part of an autoimmune process. Toxins or infections can also harm myelin or may interfere with its production.

What happens if dendrites are damaged?

“By cutting off all the dendrites, the cells would no longer be able to receive information, and we expected they might die. We were amazed to find that the cells don’t die. Instead, they regrow the dendrites completely and much more quickly than they regrow axons.

What does myelination by oligodendrocytes do?

Oligodendrocytes are the myelinating cells of the central nervous system (CNS). They are the end product of a cell lineage which has to undergo a complex and precisely timed program of proliferation, migration, differentiation, and myelination to finally produce the insulating sheath of axons.

What are oligodendrocytes responsible for?

Oligodendrocytes are specialized glial cells that wrap themselves around neurons present in the CNS. Oligodendrocytes are primarily responsible for maintenance and generation of the myelin sheath that surrounds axons. They also participate in axonal regulation and the sculpting of higher order neuronal circuits [51].

Which transcription factors may act as oncogenes to cause cancer?

The AP-1 transcription factor. Fos and Jun dimerize to form AP-1, which activates transcription of a variety of growth factor-inducible genes. G protein-coupled receptors and G proteins also act as oncogenes in some human tumors (Figure 15.29).

When does myelination occur?

Myelination (the coating or covering of axons with myelin) begins around birth and is most rapid in the first 2 years but continues perhaps as late as 30 years of age. Synaptic development is a more complicated issue.

Why are transcription factors unable to bind to the promoter?

As one example, a repressor may get in the way of the basal transcription factors or RNA polymerase, making it so they can’t bind to the promoter or begin transcription. Diagram of a repressor attached to a specific DNA sequence that is its binding site.

What do you need to know about transcription factors?

Key points: 1 Transcription factors are proteins that help turn specific genes “on” or “off” by binding to nearby DNA. 2 Transcription factors that are activators boost a gene’s transcription. 3 Groups of transcription factor binding sites called enhancers and silencers can turn a gene on/off in specific parts of the body.

How does the other end of the transcriptional activator work?

The other end of the transcriptional activator (the one not bound to the DNA) interacts with general transcription factors, helping the general transcription factors and polymerase assemble tat the nearby promoter. Other transcription factors repress transcription. This repression can work in a variety of ways.

How are transcription factors related to RNA polymerase?

Once it’s bound, the transcription factor makes it either harder or easier for RNA polymerase to bind to the promoter of the gene. Some transcription factors activate transcription. For instance, they may help the general transcription factors and/or RNA polymerase bind to the promoter, as shown in the diagram below.