Higashimoto Y, Liddle R A
Department of Medicine, Duke University, Durham, North Carolina.
Biochem Biophys Res Commun. 1994 Jun 15;201(2):964-72. doi: 10.1006/bbrc.1994.1796.
The developmental expression of the glucose-dependent insulinotropic polypeptide (GIP) gene was investigated in rat intestine. Steady state levels of GIP mRNA were determined in the intestine during fetal and postnatal development by double ribonuclease protection assays. GIP mRNA could be detected as early as day 20 of embryonic development and very low levels remained until postnatal day 3. The GIP mRNA levels increased markedly in the period between days 3 and 5 of postnatal life and then gradually increased toward adult levels. Since intron 1 of the GIP gene contains putative TATA and CCAAT boxes, and some potential cis-acting promoter elements, we examined whether or not another transcript starting from exon 2 of the GIP gene is expressed during development of rat intestine. Ribonuclease protection assays suggested that although an abbreviated transcript might exist starting from exon 2, it appears to be minor and its relative abundance is unchanged during development or following intraduodenal glucose stimulation. These observations suggest that GIP may play an important role in early postnatal development probably associated with suckling.
在大鼠肠道中研究了葡萄糖依赖性促胰岛素多肽（GIP）基因的发育表达。通过双核糖核酸酶保护试验测定胎儿期和出生后发育期间肠道中GIP mRNA的稳态水平。早在胚胎发育的第20天就能检测到GIP mRNA，直到出生后第3天一直保持极低水平。出生后第3天至第5天期间，GIP mRNA水平显著增加，然后逐渐增加至成年水平。由于GIP基因的内含子1包含假定的TATA和CCAAT框以及一些潜在的顺式作用启动子元件，我们检查了是否在大鼠肠道发育过程中表达了另一种从GIP基因外显子2起始的转录本。核糖核酸酶保护试验表明，尽管可能存在一种从外显子2起始的缩短转录本，但它似乎较少，并且在发育过程中或十二指肠内葡萄糖刺激后其相对丰度没有变化。这些观察结果表明，GIP可能在出生后早期发育中发挥重要作用，可能与哺乳有关。
