Molecular analysis of Rcd1 protein as transcriptional cofactor, which may play a important role in the transformation of muscle cells

旋毛虫感染引起卫星细胞增殖，肌细胞向护理细胞转化。Rcd1被证明是c-myb原癌基因产物的转录辅助因子。此前，我们从螺旋体肌肉幼虫的cDNA中克隆了Rcd1基因，证实Rcd1蛋白是E-S产物的一部分。因此，Rcd1可能影响宿主细胞和组织形成包膜。本研究探讨了螺旋螺旋体分泌的Rcd1蛋白对C2C12成肌细胞成肌分化的调控作用，以及Rcd1蛋白调控NF-κB和AP-1转录通路的作用。转染Rcd1基因的C2C12成肌细胞中肌原素和MyoD基因的表达明显低于未转染的C2C12成肌细胞。我们证明Rcd1是一种有效的肌肉分化抑制剂，通过激活（C2C12细胞）NF-κB和AP-1信号通路。从这些结果可以推断，Rcd1蛋白是卫星细胞增殖和肌肉细胞转化的转录因子或辅助因子。

Trichinella spp. infection causes satellite cell proliferation and transformation of muscle cell to the nurse cell. Rcd1 is shown to be a transcriptional cofactor of the c-myb proto-oncogene product. Previously, we cloned Rcd1 gene from the cDNA of T. spiralis muscle larvae, and confirmed that the Rcd1 protein is part of the E-S products. Therefore, the Rcd1 likely affects host cells and tissues for capsule formation. In the present study we investigated the effect by which the Rcd1protein secreted from T. spiralis modulates myogenic differentiation in C2C12 myoblasts, and the role of the Rcd1 protein regulated NF-κB and AP-1 transcriptional pathway. The expression of myogenin and MyoD genes in C2C12 myoblasts transfected with Rcd1 gene was significantly lower than those in non-transfected C2C12 myoblasts. And we demonstrate that Rcd1 is a potent inhibitor of muscle differentiation through activation(C2C12 cells) of NF-κB and AP-1 signaling pathway. It may be inferred from these results that the Rcd1 protein functions as a transcriptional factor or cofactor of satellite cell proliferation and muscle cell transformation.