Xu R, Teng J, Cooper T A
Department of Pathology, Baylor College of Medicine, Houston, Texas 77030.
Mol Cell Biol. 1993 Jun;13(6):3660-74. doi: 10.1128/mcb.13.6.3660-3674.1993.
We have characterized a novel positive-acting splicing element within the developmentally regulated alternative exon (exon 5) of the cardiac troponin T (cTNT) gene. The exon splicing element (ESE) is internal to the exon portions of the splice sites and is required for splicing to the 3' splice site but not the 5' splice site flanking the exon. Sequence comparisons between cTNT exon 5 and other exons that contain regions required for splicing reveal a common purine-rich motif. Sequence within cTNT exon 5 or a synthetic purine-rich motif facilitates splicing of heterologous alternative and constitutive splice sites in vivo. Interestingly, the ESE is not required for the preferential inclusion of cTNT exon 5 observed in primary skeletal muscle cultures. Our results strongly suggest that the purine-rich ESE serves as a general splicing element that is recognized by the constitutive splicing machinery.
我们已经鉴定出心脏肌钙蛋白T（cTNT）基因发育调控的可变外显子（外显子5）内的一种新型正向作用剪接元件。外显子剪接元件（ESE）位于剪接位点外显子部分的内部，是外显子侧翼3'剪接位点剪接所必需的，但不是5'剪接位点剪接所必需的。cTNT外显子5与其他包含剪接所需区域的外显子之间的序列比较揭示了一个常见的富含嘌呤的基序。cTNT外显子5内的序列或合成的富含嘌呤的基序促进体内异源可变和组成型剪接位点的剪接。有趣的是，在原代骨骼肌培养物中观察到的cTNT外显子5的优先包含并不需要ESE。我们的结果强烈表明，富含嘌呤的ESE作为一种通用的剪接元件，被组成型剪接机制所识别。
