DuBois R N, Tsujii M, Bishop P, Awad J A, Makita K, Lanahan A
Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee.
Am J Physiol. 1994 May;266(5 Pt 1):G822-7. doi: 10.1152/ajpgi.1994.266.5.G822.
Growth factors have been shown to play a role in intestinal epithelial growth regulation and transformation. Utilizing standard differential cloning techniques, we have isolated a growth factor-inducible gene (RS-2) from rat intestinal epithelial cells that has approximately 95% homology to the mouse mitogen-inducible cyclooxygenase (COX-2) at the amino acid level. This cDNA hybridizes to a approximately 4.5-kb mRNA from transforming growth factor (TGF)-alpha-stimulated rat intestinal epithelial (RIE-1) cells and is constitutively expressed in vivo in adult rat kidney and brain. Nuclear run-on experiments demonstrate that the increase of RS-2 mRNA after TGF-alpha stimulation is in part due to an increased transcription rate of the gene. The coding region for RS-2 was subcloned into a pCMV-2 expression vector, and the RS-2 protein was expressed in COS-1 cells. Microsomal fractions isolated from the COS-1 cells transfected with the RS-2 expression vector contained cyclooxygenase activity. In addition to the production of prostaglandins, the recombinant RS-2 protein also catalyzed the formation of three other eicosanoid products. In summary, we have cloned a mitogen-inducible cyclooxygenase gene from rat intestinal cells that is induced following growth factor stimulation.
生长因子已被证明在肠道上皮生长调节和转化中发挥作用。利用标准的差异克隆技术，我们从大鼠肠道上皮细胞中分离出一个生长因子诱导基因（RS-2），该基因在氨基酸水平上与小鼠丝裂原诱导型环氧化酶（COX-2）具有约95%的同源性。该cDNA与来自转化生长因子（TGF）-α刺激的大鼠肠道上皮（RIE-1）细胞的约4.5-kb mRNA杂交，并在成年大鼠肾脏和大脑中体内组成性表达。细胞核转录实验表明，TGF-α刺激后RS-2 mRNA的增加部分归因于该基因转录速率的提高。将RS-2的编码区亚克隆到pCMV-2表达载体中，并在COS-1细胞中表达RS-2蛋白。从用RS-2表达载体转染的COS-1细胞中分离的微粒体部分具有环氧化酶活性。除了产生前列腺素外，重组RS-2蛋白还催化形成其他三种类花生酸产物。总之，我们从大鼠肠道细胞中克隆了一个丝裂原诱导型环氧化酶基因，该基因在生长因子刺激后被诱导。
