Partial Overlaping between Protective Protein and Phospholipid Transfer Protein Genes

保护蛋白（Protective protein，PP）是一种多功能糖蛋白，通过在溶酶体中形成多酶复合物，稳定β-半乳糖苷酶和激活字母，调节β-半乳糖苷酶和神经氨酸酶的表达。磷脂转移蛋白（PLTP）促进磷脂的交换和转移。PLTP还具有促进调节高密度脂蛋白大小和组成的能力。在人类基因组DNA的互补链上，编码这两种蛋白的基因在其mRNA的3 '端非翻译区有58个核苷酸的部分重叠，本研究利用PCR技术对小鼠DNA的细菌人工染色体（BAC）文库进行筛选，获得了一个阳性克隆。该克隆含有完整的小鼠PP和PLTP基因。我们以克隆的DNA为模板，通过PCR扩增和随后的DNA扩增片段的测序分析，确定了这两个基因的外显子-内含子组织。小鼠PP基因跨度为6.5kb，包含15个外显子，小鼠PLTP基因跨度为18 kb，包含16个外显子。与人类基因相比，小鼠PP和PLTP基因的外显子-内含子结构非常保守。我们证实了这两个基因的mRNA的3 '-非翻译端对应的66 nt序列重叠在DNA的互补链上。

Protective protein (PP) is a multi functional glycoprotein which regulates the expression of b-galactosidase and neuraminidase, by stabilizing the former and by activating the letter, through the formation of multienzymic complex in lysosomes. Phospholipid transfer protein (PLTP) promotes the exchange and transfer of phospholipids. PLTP also has the ability to facilitate modulation of high density lipoprotein size and composition. It has been reported that genes encording both proteins are partially overlapping by 58 nucleotides at the parts of 3'-untranslated end sequences of their mRNAs on the complementary strand of Human genomic DNA.In this study, we screened a bacterial artificial chromosome (BAC) library of mouse DNA by means of PCR-based analysis, and obtained a positive clone. The clone contained the entire mouse PP and PLTP genes. We determined the exon-intron organizations of the both genes by PCR amplifications using DNA of the clone as a template, and subsequent sequencing analysis of the amplified DNA fragments. The mouse PP gene spans 6.5kb and comprises 15 exons, and the mouse PLTP gene spans 18kb and comprises 16 exons. Compared with those of the human genes, the exon-intron organizations of the mouse PP and PLTP genes were well conserved. We Confirmed that 66nt sequence corresponding to the 3'-untranslated ends of mRNAs of both genes overlapped on the complementary strand of DNA.