【摘要】 小鼠伴肌动蛋白相关锚定蛋白 (N RAP)是已知的与肌纤维生成有关的细胞骨架蛋白 ,但是 ,与此对应的人类N RAP基因的cDNA序列及其功能一直是未知的 .为了明确N RAP基因在人类中所起的作用 ,利用生物信息学分析工具和分子生物学技术 ,成功地克隆了人N RAP基因 .人N RAP基因cDNA序列含有一个 5 0 88bp的开放读码框 ,与小鼠N RAP基因有 86 %的相似性 .染色体定位分析表明 ,人N RAP基因定位于 10 q2 5～q2 6之间 ,编码区由 4 1个外显子组成 ,与HABP2和CASP7紧密连锁 .电子表达谱分析表明 ,肌肉、心脏、脑、脊髓和前列腺有人N RAP基因不同长度的cDNA序列 .人N RAP与小鼠N RAP蛋白质序列有 88%的相似性 ,与人Nebulin有约 6 3%的相似性 ,与小鼠Nebulin有约 5 9%的相似性 .结构域分析发现 ,N端为LIM结构域 ,从第170位氨基酸开始 ,连续出现 4 0个Nebulin相关重复序列 .RT PCR实验表明 ,人N RAP基因在成人脑、骨骼肌和心脏组织中都有表达 ,在骨髓中不表达 .亚细胞定位研究显示 ,人N RAP基因表达于胞浆 .基于序列相似性、结构域分析、表达谱分析和亚细胞定位研究 ,可以推测人N RAP与小鼠N RAP同属Nebulin家族 ,具有类似的功能更多还原

【Abstract】 Nebulin related anchoring protein (N RAP) is a 185 ku actin binding LIM protein recently discovered in skeletal and cardiac muscle tissues in mouse. It is proposed that N RAP serves as a link between the terminal actin of the myofibril and the protein complexes at the cell membrane and thus as an organizing center in the initial phase of myofibril assembly. But in human, the sequence and function of N RAP remain unknown. By using bioinformatics tools, the full length of human N RAP cDNA, which contains a 5 088 bp ORF, encodes a protein of 1 695 amino acid residues, is successfully cloned. Human N RAP is mapped to the genomic region between HABP2 and CASP7 at chromosome 10q25～q26, consisting of 41 exons and 40 introns. Homology searches with the deduced 1 695 amino acid protein sequence reveal human N RAP shares 88% similarity with mice N RAP, 63% with human Nebulin and 59% with mice Nebulin. Corresponding EST sequences are found in muscle, heart, spinal cord and prostate tissue. The predicted protein contains LIM domain (5～57), which binds two zinc ions, does not bind DNA, seems to act as interface for protein protein interaction, and Nebulin repeats, tandem arrays of which are known to bind actin. RT PCR reveals human N RAP is expressed in adult muscle, heart and brain tissue, not in bone marrow. In addition, subcellular location study shows human N RAP is expressed in cytoplasm. These results demonstrate that just like mice N RAP , human N RAP is proposed to be crucial for myofibrillogenesis.更多还原