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"... So, what is it about the peripheral nervous system, which connects our brain and spinal cord to the other organs, that gives it the power to regenerate itself so readily? In a new study, researchers ... have discovered that a protein, previously known to be expressed only during embryonic development, plays a key role in regenerating adult neurons in the peripheral nervous system. ...
When embryonic cells differentiate into adult nerve cells, the levels of a protein called PTBP1 decrease sharply, and this drop is thought to be key to their transformation into neurons. Previous studies have even shown that upon completing the differentiation process, adult neurons in the central nervous system cease to produce PTBP1. ...
the researchers studied the response of neurons to an injury. They found that three days after the injury, the PTBP1 levels in the cell began to rise, reaching their highest level after one week. The scientists also saw that as these levels rose, cells in the nerve branches started to regenerate. A sequencing of the messenger RNA molecules bound to PTBP1 after an injury revealed that the protein bound not only to the mail van’s RNA molecules but also to RNA molecules encoding other proteins that play roles in nerve cell regeneration. One of these proteins was RHOA, an important control molecule in both the differentiation process and cell regeneration, which acts as an “off” switch that inhibits cellular growth. ..."
When embryonic cells differentiate into adult nerve cells, the levels of a protein called PTBP1 decrease sharply, and this drop is thought to be key to their transformation into neurons. Previous studies have even shown that upon completing the differentiation process, adult neurons in the central nervous system cease to produce PTBP1. ...
the researchers studied the response of neurons to an injury. They found that three days after the injury, the PTBP1 levels in the cell began to rise, reaching their highest level after one week. The scientists also saw that as these levels rose, cells in the nerve branches started to regenerate. A sequencing of the messenger RNA molecules bound to PTBP1 after an injury revealed that the protein bound not only to the mail van’s RNA molecules but also to RNA molecules encoding other proteins that play roles in nerve cell regeneration. One of these proteins was RHOA, an important control molecule in both the differentiation process and cell regeneration, which acts as an “off” switch that inhibits cellular growth. ..."
From the abstract:
"Polypyrimidine tract binding protein 1 (PTBP1) is thought to be expressed only at embryonic stages in central neurons. Its down-regulation triggers neuronal differentiation in precursor and non-neuronal cells, an approach recently tested for generation of neurons de novo for amelioration of neurodegenerative disorders. Moreover, PTBP1 is replaced by its paralog PTBP2 in mature central neurons. Unexpectedly, we found that both proteins are coexpressed in adult sensory and motor neurons, with PTBP2 restricted mainly to the nucleus, while PTBP1 also shows axonal localization. Levels of axonal PTBP1 increased markedly after peripheral nerve injury, and it associates in axons with mRNAs involved in injury responses and nerve regeneration, including importin β1 (KPNB1) and RHOA. Perturbation of PTBP1 affects local translation in axons, nociceptor neuron regeneration and both thermal and mechanical sensation. Thus, PTBP1 has functional roles in adult axons. Hence, caution is required before considering targeting of PTBP1 for therapeutic purposes."
Fig. 2. PTBP1 is expressed in adult sensory neurons.
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