Differential expression of the alternatively spliced forms of prosaposin mRNAs in the rat choroid plexus.
Differential expression of the alternatively spliced forms of prosaposin mRNAs in the rat choroid plexus.
复制标题
大鼠脉络丛中前列腺素 mRNA 的选择性剪接形式的差异表达。
DOI：
10.1007/s00441-013-1773-9
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Marsuda S.
中科院分区：
文献类型：
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作者：
Saito S.;Saito K.;Nabeka H.;Shimokawa T.;Kobayashi N.;Marsuda S.
前列腺素有两种不同的特征。一种是前体形式，被加工成皂苷，从而促进溶酶体鞘脂水解酶功能，而另一种是完整形式，不被加工成皂苷，但在某些组织和分泌液（包括脑脊液）中含量丰富。在大鼠中，prosaposin 基因中的选择性剪接生成带有和不带有 9 碱基插入的 mRNA（分别为 Pro+9 和 Pro+0 mRNA）。据报道，Pro+9 mRNA 优先在完整形式的前塞塞辛占主导地位的组织中表达，而 Pro+0 mRNA 优先在前体形式占主导地位的组织中表达。本研究检测了大鼠脉络丛中 Pro+9 和 Pro+0 mRNA 的表达模式。通过原位杂交检测 9 碱基插入的 36 聚体寡核苷酸探针的特异性通过斑点印迹杂交得到了证明。接下来，将这些探针用于原位杂交，结果显示脉络丛中 Pro+0 mRNA 表达较多，Pro+9 mRNA 表达较弱。这些表达模式通过逆转录加上AlwI限制性酶处理的聚合酶链式反应得到证实。通过蛋白质印迹和免疫组织化学评估脉络丛中完整形式的前塞塞辛的表达。由于脉络丛负责产生含有完整形式的 prosaposin 的脑脊液，因此本研究提出了 Pro+0 mRNA 与脉络丛中的完整形式相关的可能性，并且 mRNA 的选择性剪接形式并不简单地对应于 prosaposin 的前体和完整形式。
Prosaposin has two distinct profiles. One is a precursor form that is processed into saposins thus promoting lysosomal sphingolipid hydrolase function, whereas the other is an intact form that is not processed into saposins but is abundant in certain tissues and secretory fluids, including the cerebrospinal fluid. In rats, alternative splicing in the prosaposin gene generates mRNAs with and without a 9-base insertion (Pro+9 and Pro+0 mRNAs, respectively). Pro+9 mRNA is reported to be preferentially expressed in tissues in which the intact form of prosaposin dominates, whereas Pro+0 mRNA is preferentially expressed in tissues in which the precursor dominates. The expression patterns of Pro+9 and Pro+0 mRNAs in the rat choroid plexus are examined in the present study. The specificities of 36-mer oligonucleotide probes used to detect the 9-base insertion by in situ hybridization were demonstrated by dot-blot hybridization. Next, these probes were used for in situ hybridization, which showed predominant expression of Pro+0 mRNA and weak expression of Pro+9 mRNA in the choroid plexus. These expression patterns were confirmed by reverse transcription plus the polymerase chain reaction withAlwI restriction enzyme treatment. Expression of the intact form of prosaposin in the choroid plexus was assessed by Western blotting and immunohistochemistry. Because the choroid plexus is responsible for the generation of cerebrospinal fluid containing the intact form of prosaposin, the present study raises the possibility that Pro+0 mRNA is related to the intact form in the choroid plexus and that the alternatively spliced forms of mRNAs do not simply correspond to the precursor and intact forms of prosaposin.