Molecular closing, characterization and alternative splicing of the human cytoplasmic serine hydroxymethyltransferase gene
Molecular closing, characterization and alternative splicing of the human cytoplasmic serine hydroxymethyltransferase gene
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DOI：
10.1016/s0378-1119(98)00085-7
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发表时间：
1998-04-14
期刊：
影响因子：
3.5
通讯作者：
Stover, PJ
中科院分区：
文献类型：
--
作者：
Girgis, S;Nasrallah, IM;Stover, PJ
分离人胞浆丝氨酸羟甲基转移酶（CSHMT）基因，测序并鉴定其在人MCF-7乳腺癌细胞和SH 5 Y 5 Y神经母细胞瘤细胞中的表达。23 kb的基因包含12个内含子和13个外显子;所有剪接点符合gt/ag规则。开放阅读框被10个内含子中断，其中两个在人线粒体SHMT基因内位置保守。该基因在三个外显子中表达330个核苷酸的5'非翻译信息。5'启动子区不含共有TATA，引物延伸和5'-RACE研究表明转录起始发生在多个位点。在5'启动子区的前408个核苷酸内存在几种调节蛋白的共有基序，包括SP 1、乳腺和神经元特异性元件、NF 1、Y盒和两个类固醇激素反应元件。人基因在5'非翻译区和开放阅读框内表达为多个剪接变体，所有这些都是由于外显子切除。剪接模式是细胞特异性的。MCF-7细胞中至少存在六种CSHMT mRNA剪接形式;该基因表达为全长信息以及缺少外显子2、9和10的剪接形式。在5 Y细胞中，主要形式的信息缺少外显子2，其编码部分5'非翻译区，但在开放阅读框内不包含缺失。Western分析表明，CSHMT基因在5 Y细胞中以单一全长蛋白表达，但在MCF-7细胞中以多种形式表达。多个组织的北方印迹表明，CSHMT信息水平和可变剪接模式显示组织特异性的变化。(C)1998年Elsevier Science B.V.
The human cytoplasmic serine hydroxymethyltransferase (CSHMT) gene was isolated, sequenced and its expression characterized in human MCF-7 mammary carcinoma and SH 5Y5Y neuroblastoma cells. The 23-kb gene contains 12 introns and 13 exons; all splice junctions conform to the gt/ag rule. The open reading frame is interrupted by 10 introns, two of which are positionally conserved within the human mitochondrial SHMT gene. The gene is expressed with 330 nucleotides of 5' untranslated message within three exons. The 5' promoter region does not contain a consensus TATA, and primer extension and 5'-RACE studies suggest that transcription initiation occurs at multiple sites. Consensus motifs for several regulatory proteins, including SP1, mammary and neuronal-specific elements, NF1, a Y-box, and two steroid hormone response elements, are present within the first 408 nucleotides of the 5' promoter region. The human gene is expressed as multiple splice variants in both the 5' untranslated region and within the open reading frame, all due to exon excision. The splicing pattern is cell-specific. At least six CSHMT mRNA splice forms are present in MCF-7 cells; the gene is expressed as a full-length message as well as splice forms that lack exon(s) 2, 9 and 10. In 5Y cells, the predominant form of the message lacks exon 2, which encodes part of the 5' untranslated region, but does not contain deletions within the open reading frame. Western analysis suggests that the CSHMT gene is expressed as a single full-length protein in 5Y cells, but as multiple forms in MCF-7 cells. Multiple tissue Northern blots suggest that the CSHMT message levels and alternative splicing patterns display tissue-specific variations. (C) 1998 Elsevier Science B.V.