Identification of multiple rabbit flavin-containing monooxygenase form 1 (FMO1) gene promoters and observation of tissue-specific DNase I hypersensitive sites.
Identification of multiple rabbit flavin-containing monooxygenase form 1 (FMO1) gene promoters and observation of tissue-specific DNase I hypersensitive sites.
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DOI：
10.1006/abbi.1996.0555
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发表时间：
1996-12
影响因子：
3.9
通讯作者：
Z. Luo;R. Hines
中科院分区：
文献类型：
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作者：
Z. Luo;R. Hines
我们克隆并部分鉴定了兔FMO1基因，作为了解其组织特异性表达调控机制的第一条途径。分离克隆含有14kb的5‘侧翼信息和约30kb的结构基因，但不包括3’端。定义了两个上游外显子，均编码5‘前导信息。第一个外显子称为外显子0，包含以前没有报道过的信息。第二个外显子称为外显子1，包含先前报道的兔FMO1基因的信息。编码蛋白质的信息从外显子2开始，由7个核苷酸组成。单个转录起始点位于外显子1，而一簇转录起始点位于外显子0，与两个可供选择的启动子一致。起始于外显子0的转录本由于选择性加工不包含外显子1的信息，而代表主要的FMO1mRNA。两个启动子都不包含TATA盒或GC岛，尽管外显子1启动子确实与启动子类型的元件有一些序列相同。在FMO1启动子的上游区域发现了几个已知转录因子结合位点的同源序列。这两个启动子都能有效地引导荧光素酶的表达，尽管数据与这两个启动子都需要上游增强子序列是一致的。与此观察一致的是，利用肝细胞核将DNase I超敏部位定位于外显子0上游的600个碱基对。肺组织的细胞核中未检测到此类部位。在这两种组织中也没有观察到不同的DNA甲基化。
We have cloned and partially characterized the rabbit FMO1 gene as a first approach to understanding mechanisms controlling its tissue-specific expression. The isolated clones contain 14 kb of 5' flanking information and approximately 30 kb of the structural gene, but do not include the 3'-end. Two upstream exons were defined, both encoding 5' leader information. The first exon, termed exon 0, contains information not previously reported. The second exon, termed exon 1, contains information previously reported for the rabbit FMO1 cDNA. Protein coding information begins seven nucleotides from the start of exon 2. A single transcription start site was localized in exon 1, while a cluster of sites were defined in exon 0, consistent with two alternative promoters. Transcripts initiating in exon 0 do not contain exon 1 information due to alternative processing and represent the major FMO1 mRNA. Neither promoter contains a TATA box or GC islands, although the exon 1 promoter does share some sequence identity with initiator-type elements. Homologous sequences to several known transcription factor binding sites were found in the upstream region of the FMO1 promoters. Both promoters were active in directing luciferase expression when transiently transfected into human HepG2 cells, although the data are consistent with both requiring upstream enhancer sequences. Consistent with this observation, DNase I hypersensitive sites were mapped to a 600-bp region immediately upstream of exon 0 using liver nuclei. No such sites were detected with nuclei from lung. Differential DNA methylation also was not observed between these two tissues.