Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo, Tokyo, 113-8657, Japan.
Mar Biotechnol (NY). 2011 Jun;13(3):517-26. doi: 10.1007/s10126-010-9322-y. Epub 2010 Sep 29.
Aspolin is a muscular protein having unique structural characteristics where the most part of its primary structure is occupied by aspartic acid. Aspolin has been found exceptionally in fish muscle, suggesting its specific role in this tissue. However, biological functions of aspolin have remained unknown. In the present study, we cloned full-length cDNAs encoding zebrafish Danio rerio aspolins 1 and 2, revealed their genomic organization, and examined in vivo function using knockdown techniques. Genomic analysis clearly showed that aspolin is a paralog of the histidine-rich calcium binding protein gene, which encodes a calcium binding protein in sarcoplasmic reticulum (SR). Expression analysis showed that the transcripts and their translated products, aspolins 1 and 2, are distributed in myotomal skeletal muscle, but not in cardiac muscle. Injection of antisense morpholino oligo targeting both aspolins 1 and 2 increased the mRNA levels of calsequestrin 1, another calcium binding protein in SR. These lines of evidence suggest that aspolins regulate calcium concentrations in SR.
aspolin 是一种肌肉蛋白，具有独特的结构特征，其一级结构的大部分被天冬氨酸占据。Aspolin 异常存在于鱼类肌肉中，表明其在该组织中的特定作用。然而，aspolin 的生物学功能仍然未知。在本研究中，我们克隆了编码斑马鱼 Danio rerio aspolin 1 和 2 的全长 cDNA，揭示了它们的基因组组织，并使用敲低技术研究了其体内功能。基因组分析清楚地表明，aspolin 是富含组氨酸的钙结合蛋白基因的一个旁系同源物，该基因编码肌浆网 (SR) 中的钙结合蛋白。表达分析表明，转录本及其翻译产物 aspolin 1 和 2 分布在肌节骨骼肌肉中，但不在心肌中。针对 aspolin 1 和 2 的反义 morpholino 寡核苷酸的注射增加了另一种肌浆网中钙结合蛋白 calsequestrin 1 的 mRNA 水平。这些证据表明，aspolin 调节肌浆网中的钙浓度。
