Inoue H, Riggs A C, Tanizawa Y, Ueda K, Kuwano A, Liu L, Donis-Keller H, Permutt M A
Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Diabetes. 1996 Jun;45(6):789-94. doi: 10.2337/diab.45.6.789.
Insulin promoter factor 1 (IPF-1) is a homeodomain-containing protein that is thought to be a key regulator of pancreatic islet development and insulin gene transcription in beta-cells. This report describes the isolation and characterization of the human IPF-1 gene. The coding region, which showed 83% nucleotide identity with the mouse IPF-1 gene, was encoded by two exons that extended over a 5-kb region of human genome. The deduced human IPF-1 protein contained 283 amino acids, 1 amino acid less than the mouse IPF-1 protein. The homeodomain region of IPF-1 was encoded by the second exon, and it was highly conserved among species. The human IPF-1 gene was mapped to chromosome 13q12(12.1) by fluorescent in situ hybridization (FISH) analysis. A simple sequence repeat polymorphism (ipf1CA2) was identified in the genomic clone. Polymerase chain reaction (PCR) amplification of this repeat region revealed two alleles (heterozygosity = 0.32). This simple sequence repeat polymorphism, and thus the IPF-1 gene, was incorporated into the human linkage map by genotyping reference Human Polymorphism Study Center (CEPH) pedigrees. Multipoint analysis with the CEPH genotype database placed the gene with equal likelihood between two marker intervals: D13S292-cdx3GA1 and cdx3GA1-D13S289 on chromosome 13, consistent with the results of FISH analysis. Two-point linkage analysis inferred that the most likely location for ipf1CA2 was at theta = 0 from cdx3GA1 locus. The exon-intron boundaries of the IPF-1 gene were sequenced, and primers were synthesized to search the homeodomain region for potential variants in patients with NIDDM. By single-strand conformational polymorphism analysis, no variants were found within this region in 61 Japanese patients, which could contribute to the pathogenesis of NIDDM. The isolation of the human IPF-1 gene, along with characterization of its genomic structure and chromosomal mapping, will now permit the assessment of the role of this gene in the pathogenesis of NIDDM in various populations.
胰岛素启动子因子1（IPF-1）是一种含同源结构域的蛋白质，被认为是胰岛发育和β细胞中胰岛素基因转录的关键调节因子。本报告描述了人类IPF-1基因的分离与特性。编码区与小鼠IPF-1基因有83%的核苷酸同一性，由两个外显子编码，跨越人类基因组的5kb区域。推导的人类IPF-1蛋白包含283个氨基酸，比小鼠IPF-1蛋白少1个氨基酸。IPF-1的同源结构域区域由第二个外显子编码，在物种间高度保守。通过荧光原位杂交（FISH）分析，将人类IPF-1基因定位于染色体13q12(12.1)。在基因组克隆中鉴定出一个简单序列重复多态性（ipf1CA2）。对该重复区域进行聚合酶链反应（PCR）扩增，揭示了两个等位基因（杂合度=0.32）。通过对参考人类多态性研究中心（CEPH）家系进行基因分型，将这种简单序列重复多态性以及IPF-1基因纳入人类连锁图谱。利用CEPH基因型数据库进行多点分析，该基因在13号染色体上的两个标记区间D13S292-cdx3GA1和cdx3GA1-D13S289之间出现的可能性相等，这与FISH分析结果一致。两点连锁分析推断，ipf1CA2最可能的位置在距cdx3GA1位点θ=0处。对IPF-1基因的外显子-内含子边界进行测序，并合成引物以在非胰岛素依赖型糖尿病（NIDDM）患者的同源结构域区域寻找潜在变异。通过单链构象多态性分析，在61名日本患者的该区域未发现可能导致NIDDM发病机制的变异。人类IPF-1基因的分离及其基因组结构和染色体定位的特性，现在将允许评估该基因在不同人群NIDDM发病机制中的作用。
