Human genetic analysis on the regulation of Duffy gene expression.

已证明Duffy基因的基因组结构没有被内含子分割，即使在其5‘和3’非翻译区也是如此。IL-8受体基因是Duffy基因的高度同源基因，在编码区内不被内含子分割，而是在5‘非翻译区分裂。然后，我们通过5‘-RACE对转录起始位置进行了重新分析，发现了一个新的第一外显子和剪接形式的mRNA，它在红系和毛细血管后微静脉内皮细胞中都是主要的转录本。新的第一外显子的5‘侧翼区被认为是这两个组织的转录控制单位。而在红系细胞上游48个碱基的转录起始点位于内温层。48个碱基包括GATA转录因子的反向共识结合位点。我们在具有FY(a-b-)表型的黑人个体中发现了GATA基序上的纯合子1个碱基替换。…中的FY(a-b-)更多的个体被证明不是在骨髓中产生Duffy mRNA，而是在内皮细胞中产生它。FY(a-b-)的组织特异性表达缺失表明Duffy基因的转录调控受到严格的组织特异性调控。将新的第一外显子5‘侧翼区插入到CAT报告基因的上游，并对转录调控效率进行了分析。Duffy阳性的启动子序列有效地转录了报告基因在红系细胞和内皮细胞中。当在GATA基序中引入Duffy负离子的一个碱基取代时，红系细胞中的启动子活性完全减弱。这些数据清楚地解释了黑色型FY(a-b-)中Duffy基因表达的红系特异性中断。除间日疟原虫外的选择性压力对FY(a-b-)个体沿内皮细胞Duffy糖蛋白的保存和西非表型的确定有待进一步研究。较少

The genomic structure of Duffy gene has been shown not to be split by introns, even in its 5' and 3' untranslated regions. The genes of IL-8 receptors, which are the highly homologous genes of Duffy gene, are not split by introns within the coding regions but are split in the 5' untranslated regions. Then we reanalyzed the transcriptional start position by 5'-rapid amplification of cDNA ends (5'-RACE), and identified a novel first exon and spliced form mRNA that was predominant transcript in both erythroid and postcapillary venule endothelium. The 5' flanking region of the novel first exon was regarded as the transcription controlling unit for both tissues. However, the transcriptional start position in endotherium was 48 bases upstream from that of the erythroid cells. And the 48 bases included an inverted consensus binding site for the GATA transcription factor. We found homozygous one base substitution at the GATA motif in black individuals with Fy (a-b-) phenotype. The Fy (a-b-) in … More dividuals have been shown not to produce Duffy mRNA in the bone marrow, but to produce it in endothelial cells. The tissue-specific lacking of expression in Fy (a-b-) indicates that the transcription control of Duffy gene is under tight tissue-specific regulation. The 5' flanking region of the novel first exon was inserted in the upstream of CAT reporter gene and was analyzed the transcription controlling efficiency. The promotor sequence of Duffy positives efficiently transcribed the reporter gene in both erythroid and endothelial cells. When one base substitution of Duffy negatives was introduced in the GATA motif, the promotor activity in erythroid cells was completely diminished. These data clearly explain the erythroid specific disruption of Duffy gene expression in black type Fy (a-b-). The selective pressure other than Plasmodium vivax have to be studied in the future on the saving of Duffy glycoprotein along endothelial cells in Fy (a-b-) individuals and the fixing the phenotype in West Africa. Less