Evaluation of the amino-acid polymorphism identified in the insulin gene transcription factor A1

胰岛素基因转录因子A1氨基酸多态性的评价

• 批准号: 05807088
• 负责人: YAMASAKI Yoshimitsu
• 金额: $ 1.34万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05807088/
• 关键词: inslin gene; transcription; polymorphism; molecular biology; 選択的スプライシング; 転写因子; 多型性

Two basic helix-loop-helix (bHLH) transcription factors, E47 and E12, are involved in the insulin geneexpression as part of dimeric complexes which interact with the cis-acting motif, E-box. Although both generated from a single gene (E2A) by means of alternative splicing, the structural difference in these bHLH regions between the two suggests that two bHLH proteins may differ in some of their functions. We reccuntly indentified an amino acid (aa) polymorphism in the highly conserved region within the leucine zipper (LZ) motif. Interestingly, the location and pattern of aa delections are identical to those previously described for the aa polymorphism within the human counterpart, E47 (E12) [Cell60 (1990) 547-555], which was insertion or deletion of glutamine.To explore the possible physiological meaning of the polymorphism, we surveyed seven mouse strains (C57BL/6 ob/ob, C57BL/6J,C57BL/KsJ,ICR,BALB/c ByJ,DBA/2J and C3H/HeJ) in terms of the type of this polymorphism. The LZ regions of … More the AI cDNAs (nt31-401) were cloned and DNA-sequenced. Among the seven strains that we examined, six had the glutamine (-)-type A1, suggesting that this type of A1 is rather prevalent in terms of numbers of strains. Only the C3H strain had the glutamine (+)-type A1. Because the C3H strain is known to be relatively hyperinsulinemic, the possible physiological significance was suggested. However, the two types of A1, when expressed in CHO cells, revealed the same DNA-binding activity, suggesting that they retains the same DNA-binding activity at least in CHO cells.To elucidate the individual implications of E47 and E12, we also investigated the mRNA expression ratios of their homologues (A1 and KA1, respectively) in mouse tissues and cell lines. Measurement using reverse-transcription polymerase chain reaction and a specific oligodeoxyribonucleotide hybridization technique revealed that both the A1 and kA1 mRNAs were ubiquitously expressed in all tissues examined. However, their ratios varied : e.g.skeletal muscle, 2.2<plus-minus>0.3 (mean<plus-minus>SE), spleen, 2.0<plus-minus>0.2, pancreatic islet cells, 1.2<plus-minus>0.2. The A1 kA1 ratios in the cell lines investigated were similar to those of their original tissues. The ubiquity in mRNA expression observed for both the E47 and E12 homologues in mouse provides support for their involvement in a broad range of transcriptional regulation. The variation in the A1/kA1 expression ratios, on the other hand, supports the idea that A1 (E47) and KA1 (E12) each have some unique roles in the functions of these E2A geneencoded bHLH p Less

两个基本的螺旋-环-螺旋（bHLH）转录因子E47和E12作为二聚体复合物的一部分参与胰岛素基因表达，并与顺式作用基序E-box相互作用。尽管它们都是通过选择性剪接从单个基因（E2A）产生的，但两者之间bHLH区域的结构差异表明，两种bHLH蛋白可能在某些功能上有所不同。我们最近在亮氨酸拉链（LZ）基序的高度保守区域发现了一个氨基酸（aa）多态性。有趣的是，aa缺失的位置和模式与之前描述的人类对应基因E47 (E12) [Cell60(1990) 547-555]中的aa多态性相同，这是谷氨酰胺的插入或缺失。为了探讨该多态性可能的生理意义，我们调查了7个小鼠品系（C57BL/ 6ob /ob、C57BL/6J、C57BL/KsJ、ICR、BALB/c ByJ、DBA/2J和C3H/HeJ）的多态性类型。克隆了更多的AI cdna （nt31-401）的LZ区并进行了dna测序。在我们检测的7株菌株中，有6株具有谷氨酰胺（-）型A1，表明这种A1型在菌株数量上相当普遍。只有C3H菌株具有谷氨酰胺（+）型A1。由于已知C3H菌株具有相对高胰岛素血症，因此提出了可能的生理意义。然而，当两种A1在CHO细胞中表达时，显示出相同的dna结合活性，这表明它们至少在CHO细胞中保持相同的dna结合活性。为了阐明E47和E12的个体意义，我们还研究了它们的同系物（分别为A1和KA1）在小鼠组织和细胞系中的mRNA表达率。使用逆转录聚合酶链反应和特异性寡脱氧核糖核苷酸杂交技术进行测量显示，A1和kA1 mrna在所有检查的组织中都普遍表达。但其比值各不相同：骨骼肌，2.2<正负>.3（平均<正负>SE），脾脏，2.0<正负>.2，胰岛细胞，1.2<正负>.2。所研究的细胞系的A1 - kA1比值与其原始组织相似。小鼠中E47和E12同源物的mRNA表达普遍存在，这为它们参与广泛的转录调控提供了支持。另一方面，A1/kA1表达比例的变化支持了A1 （E47）和kA1 （E12）在这些E2A基因编码的bHLH p Less的功能中各自具有一些独特作用的观点

项目成果

Watada H,Kajimoto Y,et al.: "Ubiquitous but variable expression of two alternatively spliced mRNAs encoding mouse homologues of transcription factors E47 and E12." Gene. 153. 255-259 (1995)

Watada H、Kajimoto Y 等人：“编码小鼠转录因子 E47 和 E12 同源物的两种可变剪接 mRNA 的普遍存在但可变的表达。”

Hirotaka Watada: "Ubizuitous,but variable,expression of two alternatively spliced mRNAs encoding mouse homeologues of transcription facturs E47 and E12." Gene. (発売予定).

Hirotaka Watada：“编码小鼠转录因子 E47 和 E12 同源基因的两种可变剪接的 mRNA 的表达（待发布）。”

Hideaki Kaneto: "Apoptotic cell death triggered by nitric oxide in pancreatic β-cells." Diabetes. 44. 733-738 (1995)

Hideaki Kaneto：“胰腺 β 细胞中一氧化氮引发的细胞凋亡。”44. 733-738 (1995)

Hirotaka Watada: "Ubiquitous,but variable,expression of two altematively spliced mRNAs encoding mouse homologues of transcription factors E47 and E12." Gene. 153. 255-259 (1995)

Hirotaka Watada：“编码小鼠转录因子 E47 和 E12 同源物的两种可变剪接 mRNA 的表达无处不在，但存在差异。”

Umayahara Y,et al.: "Estrogen regulation of the chicken insulin-like growth factor I gene involves an AP-1 enhancer." J Biol Chem.269. 16433-16442 (1994)

Umayahara Y 等人：“鸡胰岛素样生长因子 I 基因的雌激素调节涉及 AP-1 增强子。”