Cloning and Characterization of 5′-Upstream Sequence of the M32 Gene for a Mouse Homologue of Drosophila Heterochromatin Protein 1 (HP1)-猫眼课题宝

果蝇异染色质蛋白 1 (HP1) 小鼠同源物 M32 基因 5 上游序列的克隆和表征

DOI：

发表时间：

2001

期刊：

DNA Sequence

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文献类型：

作者：

M. Sato;K. Miyado;M. Kimura

M32 [也称为染色质修饰蛋白2（MOD 2）]是一种由浓缩的染色质结构（异染色质）组成的核蛋白，被认为是异染色质蛋白1（HP 1）的哺乳动物同源物之一，首先在果蝇中分离出异染色质的组分之一。本文报道了小鼠M32基因5′上游区的分离和鉴定，该基因含有一个启动子区和一个5′非翻译区（5′ UTR）外显子。M32基因5′上游（从5′-UTR外显子5′端开始约0.27 kb）不含TATA盒和CCAAT盒，但具有Sp1、H4 TF-1、PEA 2、PEA 3、GSG元件和Egr-1等转录因子的潜在结合位点，且富含G/C。该5′-上游区域的启动子活性通过其融合构建体与E. coli β-半乳糖苷酶基因转染小鼠畸胎瘤细胞系F9。mRNA的5′端至少定位于5′上游区的两个位置。有趣的是，5′-上游区域显示出高度的相似性，一部分的异质核核糖核蛋白（hnRNP）A2/B1基因，这被认为是在RNA加工中发挥作用，位于相反方向的M32基因，也是一些已知的EST和cDNA。这些结果表明，M32基因的5′-上游区域由一个多重调控复合物组成，可能在核功能如染色质组织和RNA加工中发挥重要作用。

M32 [also termed chromatin modifier protein 2 (MOD2)] is a nuclear protein consisting of the condensed chromatin structure (heterochromatin) and considered one of the mammalian homologues of heterochromatin protein 1 (HP1), first isolated as one of the components of heterochromatin in Drosophila. This report presents the isolation and characterization of the 5′-upstream region of the mouse M32 gene containing a promoter region and 5′-untranslated region (5′-UTR) exon. The 5′-upstream region (approximately 0.27 kb starting from the 5′ end of the 5′-UTR exon) of the M32 gene contained neither a TATA box nor a CCAAT box, but possessed potential binding sites for transcription factors such as Spl, H4TF-1, PEA2, PEA3, GSG element and Egr-1, and was highly G/C-rich. The promoter activity of this 5′-upstream region was demonstrated by transfecting its fusion-construct with the E. coli β-galactosidase gene into the F9 mouse teratocarcinoma cell line. The 5′ ends of the mRNA were mapped to at least two positions in the 5′-upstream region. Interestingly, the 5′-upstream region exhibited a high degree of similarity to a portion of heterogeneous nuclear ribonucleo-protein (hnRNP) A2/B1 gene, which is thought to play a role in RNA processing, located in the reverse orientation to the M32 gene, and also to several known ESTs and cDNAs. These findings suggest that the 5′-upstream region of the M32 gene consists of a multiple regulatory complex which probably plays important roles in nuclear function such as chromatin organization and RNA processing.