Riggs A C, Tanizawa Y, Aoki M, Wasson J, Ferrer J, Rabin D U, Vaxillaire M, Froguel P, Permutt M A
Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, USA.
Diabetes. 1995 Jun;44(6):689-94. doi: 10.2337/diab.44.6.689.
Islet-1 (Isl-1) is a unique transcription factor that binds to the enhancer region of the insulin gene. To evaluate this gene in non-insulin-dependent diabetes mellitus (NIDDM), a full-length human Isl-1 cDNA was isolated and the genomic structure was characterized. The cDNA [2,395 bp plus additional poly(A) residues] contained an open reading frame from an initiator methionine at nucleotide 240 to an opal stop codon at nucleotide 1,286 (GenBank accession number UO7559), encoding a predicted protein of 349 amino acids (39 kDa). From their ends, 23 additional clones were sequenced, revealing 15 incomplete cDNAs and 8 intron-containing partially processed precursors. As determined by Northern blotting and reverse transcriptase-polymerase chain reaction analysis, Isl-1 was most abundantly expressed as a 2.4-kb mRNA in human islets, with a restricted pattern of expression in other adult human tissues. Analysis of genomic clones revealed that Isl-1 is encoded by six exons, varying in size from 168 bp (exon 5) to 1,230 bp (exon 6). Exons 2 and 3 each encode a LIM domain, while the homeodomain is completely contained within exon 4.(ABSTRACT TRUNCATED AT 250 WORDS)
胰岛-1（Isl-1）是一种独特的转录因子，可与胰岛素基因的增强子区域结合。为了评估该基因在非胰岛素依赖型糖尿病（NIDDM）中的作用，分离出了全长人Isl-1 cDNA并对其基因组结构进行了表征。该cDNA[2395 bp加上额外的聚腺苷酸（A）残基]包含一个开放阅读框，从核苷酸240处的起始甲硫氨酸到核苷酸1286处的乳白终止密码子（GenBank登录号UO7559），编码一个预测的349个氨基酸（39 kDa）的蛋白质。从其末端对另外23个克隆进行了测序，发现15个不完整的cDNA和8个含内含子的部分加工前体。通过Northern印迹和逆转录酶-聚合酶链反应分析确定，Isl-1在人胰岛中以2.4 kb的mRNA最丰富地表达，在其他成人组织中的表达模式有限。对基因组克隆的分析表明，Isl-1由六个外显子编码，大小从168 bp（外显子5）到1230 bp（外显子6）不等。外显子2和3各自编码一个LIM结构域，而同源结构域完全包含在外显子4中。（摘要截断于250字）
