Wnt proteins are a large family of diffusible factors that play important roles in embryonic development, including axis patterning, cell fate specification, proliferation, and axon development. It was recently demonstrated that Ryk (receptor related to tyrosine kinase) is a conserved high-affinity Wnt receptor, and that Ryk-Wnt interactions guide corticospinal axons down the spinal cord during development. Here, we report that the Ryk-Wnt signal mediates the inhibition of corticospinal axon growth in the adult spinal cord. The expression of Wnt-5a is induced in reactive astrocytes around the injury site following a spinal cord injury. In vitro, Wnt-5a inhibits the neurite growth of postnatal cerebellar neurons by activating RhoA/Rho-kinase. In rats with thoracic spinal cord contusion, intrathecal administration of a neutralizing antibody to Ryk resulted in significant axonal growth of the corticospinal tract and enhanced functional recovery. Thus, reexpression of the embryonic repulsive cues in adult tissues contributes to the failure of axon regeneration in the central nervous system.
Fused in sarcoma/translocated in liposarcoma (FUS/TLS) is one of causative genes for familial amyotrophic lateral sclerosis (ALS). In order to identify binding partners for FUS/TLS, we performed a yeast two-hybrid screening and found that protein arginine methyltransferase 1 (PRMT1) is one of binding partners primarily in the nucleus. In vitro and in vivo methylation assays showed that FUS/TLS could be methylated by PRMT1. The modulation of arginine methylation levels by a general methyltransferase inhibitor or conditional over-expression of PRMT1 altered slightly the nucleus-cytoplasmic ratio of FUS/TLS in cell fractionation assays. Although co-localized primarily in the nucleus in normal condition, FUS/TLS and PRMT1 were partially recruited to the cytoplasmic granules under oxidative stress, which were merged with stress granules (SGs) markers in SH-SY5Y cell. C-terminal truncated form of FUS/TLS (FUS-dC), which lacks C-terminal nuclear localization signal (NLS), formed cytoplasmic inclusions like ALS-linked FUS mutants and was partially co-localized with PRMT1. Furthermore, conditional over-expression of PRMT1 reduced the FUS-dC-mediated SGs formation and the detergent-insoluble aggregates in HEK293 cells. These findings indicate that PRMT1-mediated arginine methylation could be implicated in the nucleus-cytoplasmic shuttling of FUS/TLS and in the SGs formation and the detergent-insoluble inclusions of ALS-linked FUS/TLS mutants.
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JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.
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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.