Canis familiaris telomerase reverse transcriptase undergoes alternative splicing
Canis familiaris telomerase reverse transcriptase undergoes alternative splicing
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DOI：
10.1007/s00335-008-9144-7
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发表时间：
2008-09-01
期刊：
影响因子：
2.5
通讯作者：
Velmmas, Joannis
中科院分区：
文献类型：
--
作者：
Angelopoulou, Katerina;Zavlaris, Michael;Velmmas, Joannis
端粒酶是细胞增殖和肿瘤发生所必需的。端粒酶逆转录酶（TERT）代表该酶的催化亚基。在人类身上。TERT的表达受几种不同机制的调控，包括选择性剪接。家犬（Canis familiaris）的TERT（dogTERT）已被证明与人的TERT具有高水平的序列相似性，表明狗可能代表一个合适的动物模型端粒酶研究。在本报告中，我们试图调查dogTERT是否经历选择性剪接。在通过RT-PCR分析犬乳腺组织（肿瘤和与肿瘤相邻的配对正常组织）的dogTERT表达期间，我们确定了8个样本-1个肿瘤和7个相邻的正常-其中含有意想不到大小的PCR产物。DNA测序显示两个插入（175和28长）和两个缺失（17和32长），这是在不同的组合和洞穴上升到五个不同的转录。所有变体的产生可以通过在dogTERT基因组序列内采用选择性剪接位点来解释。175-bp和28-bp的插入，确定之间的外显子7和8之间和8和9，分别构成未剪接序列的内含子7和8，分别。这两种缺失均源于选择性剪接导致的外显子8序列缺失。所有五个变体编码截短的蛋白质，缺乏逆转录的必要基序，因此可能失去了组成活性端粒酶的能力。这是第一次在dogTERT中鉴定出选择性剪接事件。本文的结果可能为更深入地研究犬正常细胞和癌细胞端粒酶活性的调控提供基础。
The enzyme telomerase is essential for cell proliferation and tumorigenesis. Telomerase reverse transcriptase (TERT) represents the catalytic subunit of the enzyme. In humans. TERT expression is regulated by several different mechanisms, including alternative splicing. Canis familiaris TERT (dogTERT) has been shown to have a high level of sequence similarity with human TERT, indicating that the dog may represent a suitable animal model for telomerase studies. In the present report we sought to investigate whether dogTERT undergoes alternative splicing. During the analysis of canine mammary tissues (both tumor and paired adjacent to the tumor normal tissues) for dogTERT expression by RT-PCR, we identified eight samples-one tumor and seven adjacent normal-which cave PCR products of unexpected sizes. DNA sequencing revealed two insertions (175 and 28 by long) and two deletions (17 and 32 by long), which were encountered in different combinations and cave rise to five different transcripts. The generation of all variants could be explained by the employment of alternative splicing sites within dogTERT genomic sequences. The 175-bp and 28-bp insertions, identified between exons 7 and 8 and between 8 and 9, respectively, constituted unspliced sequences of introns 7 and 8, respectively. Both deletions originated from exon 8 sequence removals due to alternative splicing. All five variants encoded truncated proteins, which lacked essential motifs for reverse transcription and might have thus lost their ability to compose active telomerase enzymes. This is the first identification of alternative splicing events within dogTERT The results presented here may provide the basis for more thorough studies on the regulation of telomerase activity in canine normal and cancer cells.