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cDNA that encodes active agrin
K W Tsim1, M A Ruegg, G Escher
1Department of Neurobiology, Stanford University School of Medicine, California 94305-5401.
Neuron
|April 1, 1992
Summary
Researchers identified active agrin in chick brains, crucial for neuromuscular junctions. A specific 33 bp insertion in agrin cDNA enhances acetylcholine receptor (AChR) and acetylcholinesterase (AChE) aggregation.
Area of Science:
- Neuroscience
- Molecular Biology
- Developmental Biology
Background:
- Agrin is a key protein at the neuromuscular junction, mediating the clustering of acetylcholine receptors (AChRs) and acetylcholinesterase (AChE).
- Understanding agrin's structure and function is vital for comprehending neuromuscular synapse formation and maintenance.
Purpose of the Study:
- To isolate and characterize chick agrin cDNA.
- To investigate the role of a specific 33 bp insertion in agrin's functional activity.
- To confirm the expression of active agrin transcripts in motor neurons.
Main Methods:
- cDNA library screening from chick brain.
- Sequence homology analysis with ray and rat agrin.
- In situ hybridization and PCR on spinal cord mRNA.
- Expression experiments to assess protein activity.
Main Results:
- Isolation of a chick agrin cDNA encoding active agrin.
- Identification of a 33 bp insertion in chick agrin, absent in ray and rat, which confers AChR/AChE aggregating activity.
- Detection of homologous transcripts with the 33 bp insertion in the ray central nervous system (CNS).
- Confirmation of active agrin transcripts in motor neuron-enriched spinal cord fractions.
Conclusions:
- Agrin's 33 bp insertion is a conserved feature in vertebrates, enhancing its neuromuscular junction organizing capabilities.
- Motor neurons express transcripts encoding active agrin, supporting its role in neuromuscular synapse development.
- This study provides molecular evidence for agrin's function in neuromuscular junction formation.