Noakes P G, Phillips W D, Hanley T A, Sanes J R, Merlie J P
Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri 63110.
Dev Biol. 1993 Jan;155(1):275-80. doi: 10.1006/dbio.1993.1025.
The 43K protein is a cytoplasmic peripheral membrane protein concentrated subsynaptically in skeletal muscle. Recombinant 43K has been shown to cause clustering of acetylcholine receptors (AChRs) in cultured cells. However, the role of 43K in vivo is disputed, because in some cases it appears only after AChRs have clustered. We therefore examined the expression and distribution of 43K and AChRs during synapse formation in embryonic mouse muscles. Messenger RNA for 43K was detected on Embryonic Day (E) 12, a day prior to the first AChR clusters. Immunofluorescence showed that both AChRs and 43K were colocalized in patches by E13, the stage at which intramuscular nerves were first detected. The AChR/43K patches were nerve associated, and more than 98% of AChR patches were accompanied by 43K. The precise colocalization of 43K and AChRs persisted through development. These results are consistent with 43K being involved in the nerve-induced clustering of AChRs during synapse formation.
43K蛋白是一种细胞质外周膜蛋白，在骨骼肌突触下集中分布。重组43K已被证明可在培养细胞中引起乙酰胆碱受体（AChR）聚集。然而，43K在体内的作用存在争议，因为在某些情况下，它仅在AChR聚集后才出现。因此，我们研究了胚胎小鼠肌肉突触形成过程中43K和AChR的表达及分布。在胚胎第12天（E12），即第一个AChR簇出现的前一天，检测到了43K的信使RNA。免疫荧光显示，到E13时，AChR和43K均共定位成斑，此时首次检测到肌内神经。AChR/43K斑与神经相关，超过98%的AChR斑伴有43K。43K和AChR的精确共定位在整个发育过程中持续存在。这些结果与43K在突触形成过程中参与神经诱导的AChR聚集一致。
