Hayward B E, Dunlop N, Intody S, Leek J P, Markham A F, Warner J P, Bonthron D T
University of Edinburgh, Department of Medicine, Western General Hospital, United Kingdom.
Genomics. 1998 Apr 1;49(1):137-42. doi: 10.1006/geno.1997.5195.
Glucokinase plays an important role in regulating insulin secretion in response to changes in blood glucose levels. As a result, one form of maturity onset diabetes of the young (MODY) results from haploinsufficiency of glucokinase. In both liver and pancreatic islet, glucokinase is allosterically regulated by an inhibitory protein (glucokinase regulatory protein, GCKR). GCKR has therefore become an important gene for functional analysis in type 2 diabetes. To allow genetic assessment of any such role, we have determined the structure of the human GCKR gene. Characterization of P1 and YAC clones containing GCKR shows it to consist of 19 exons spanning 27 kb. RT-PCR, RACE, and RNase protection experiments defined a transcriptional start site for GCKR 66 bp upstream of the initiation codon, but provided no evidence for islet cell specific alternative splicing in the rat. By SSCP screening, a common polymorphic sequence variant has been defined within exon 15 of human GCKR, at nt 1400 of the cDNA. This alters amino acid residue 446 from proline, conserved in rat and Xenopus, to leucine.
葡萄糖激酶在响应血糖水平变化调节胰岛素分泌方面发挥着重要作用。因此，一种青少年发病的成年型糖尿病（MODY）是由葡萄糖激酶单倍体不足引起的。在肝脏和胰岛中，葡萄糖激酶均受到一种抑制性蛋白（葡萄糖激酶调节蛋白，GCKR）的变构调节。因此，GCKR已成为2型糖尿病功能分析的重要基因。为了对任何此类作用进行基因评估，我们确定了人类GCKR基因的结构。对包含GCKR的P1和YAC克隆的表征表明，它由19个外显子组成，跨度为27 kb。RT-PCR、RACE和核糖核酸酶保护实验确定了GCKR在起始密码子上游66 bp处的转录起始位点，但没有提供大鼠胰岛细胞特异性可变剪接的证据。通过SSCP筛选，在人类GCKR第15外显子内、cDNA的第1400位核苷酸处定义了一个常见的多态性序列变体。这将氨基酸残基446从在大鼠和爪蟾中保守的脯氨酸改变为亮氨酸。
