Kamholz J, de Ferra F, Puckett C, Lazzarini R
Proc Natl Acad Sci U S A. 1986 Jul;83(13):4962-6. doi: 10.1073/pnas.83.13.4962.
We have isolated cDNA clones encoding three separate forms of human myelin basic protein (MBP), 21.5, 18.5, and 17.2 kDa, and have determined the nucleotide sequence of each. The three forms share a common sequence but differ by the inclusion of a 26-residue amino acid sequence near the N terminus of the 21.5-kDa protein or by the absence of an 11-residue amino acid sequence near the C terminus of the 17.2-kDa protein. The sequences either added to or deleted from the major 18.5-kDa MBP correspond exactly to exons 2 and 5 of the mouse MBP gene, suggesting that the human and mouse genes have similar exon structures. We have also identified the 21.5-kDa human MBP on immunoblots using antisera raised to a peptide encoded by the mouse exon 2 sequence. Southern blotting studies of human genomic DNA reveal a simple pattern consistent with a single human MBP gene. Thus, the three MBP mRNAs are likely to arise from alternative splicing of a primary human MBP transcript. Conservation of the 26 amino acid mouse exon 2 sequence in human MBP suggests an important role for this sequence in myelination.
我们分离出了编码三种不同形式人髓鞘碱性蛋白（MBP）的cDNA克隆，其分子量分别为21.5 kDa、18.5 kDa和17.2 kDa，并测定了每种克隆的核苷酸序列。这三种形式共享一个共同序列，但存在差异：21.5 kDa蛋白的N端附近包含一段26个氨基酸的序列，或者17.2 kDa蛋白的C端附近缺少一段11个氨基酸的序列。添加到主要的18.5 kDa MBP上或从其删除的序列正好对应于小鼠MBP基因的外显子2和外显子5，这表明人和小鼠的基因具有相似的外显子结构。我们还使用针对由小鼠外显子2序列编码的肽产生的抗血清，在免疫印迹上鉴定出了21.5 kDa的人MBP。对人基因组DNA的Southern印迹研究揭示了一种与单个人MBP基因一致的简单模式。因此，这三种MBP mRNA可能源于人MBP初级转录本的可变剪接。人MBP中26个氨基酸的小鼠外显子2序列的保守性表明该序列在髓鞘形成中起重要作用。
