Séguin D, Desforges M, Rassart E
Département des Sciences Biologiques, Université du Québec à Montréal, Canada.
Brain Res Mol Brain Res. 1995 Jun;30(2):242-50. doi: 10.1016/0169-328x(95)00008-g.
The mouse apolipoprotein D gene was isolated from a brain cDNA library. The nucleotide sequence contains a unique reading frame coding for a protein sharing 79.5% homology with human apoD, 86.2% homology with rabbit apoD and 92.6% homology with rat apoD. The four sequences have two potential asparagine-linked glycosylation sites at residues 45 and 78, and possess the two consensus sequences of the lipocalin family which coincide with the most conserved regions in the four species studied. The distribution of apoD mRNA among mouse organs was determined by Northern blot and quantitative dot blot analysis. The highest levels of mRNA were found in the central nervous system (CNS), namely in the spinal cord, the cerebellum and the brain. Very low concentrations were detected in all the other organs tested. In some organs (spleen, kidney, intestines, heart), a second messenger of lower molecular weight was detected. Gene expression was also measured in rat tissues. As in the mouse, rat CNS was found to be by far the highest expressor of apoD mRNA, in contrast to the rabbit and human. Levels of expression in most mouse and rat organs appeared to be much lower than in the same organs of the rabbit and human. Since apoD is expressed at sites of nerve regeneration as well as apoE, our results raise the question of whether or not the two proteins play a coordinated role in the CNS.
从小鼠脑cDNA文库中分离出小鼠载脂蛋白D基因。核苷酸序列包含一个独特的阅读框，编码一种与人类载脂蛋白D有79.5%同源性、与兔载脂蛋白D有86.2%同源性、与大鼠载脂蛋白D有92.6%同源性的蛋白质。这四个序列在第45和78位残基处有两个潜在的天冬酰胺连接的糖基化位点，并拥有脂钙蛋白家族的两个共有序列，这两个序列与所研究的四个物种中最保守的区域一致。通过Northern印迹和定量斑点印迹分析确定了载脂蛋白D mRNA在小鼠各器官中的分布。在中枢神经系统（CNS），即脊髓、小脑和大脑中发现了最高水平的mRNA。在所有其他测试器官中检测到的浓度非常低。在一些器官（脾脏、肾脏、肠道、心脏）中，检测到一种分子量较低的第二信使。也对大鼠组织中的基因表达进行了检测。与小鼠一样，与兔和人类相比，大鼠中枢神经系统被发现是载脂蛋白D mRNA的最高表达部位。大多数小鼠和大鼠器官中的表达水平似乎远低于兔和人类相同器官中的表达水平。由于载脂蛋白D与载脂蛋白E一样在神经再生部位表达，我们的结果提出了这两种蛋白质在中枢神经系统中是否发挥协同作用的问题。
