Identification and characterization of a novel human cathepsin L splice variant
Identification and characterization of a novel human cathepsin L splice variant
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DOI：
10.1016/s0378-1119(02)00700-x
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发表时间：
2002-06-26
期刊：
影响因子：
3.5
通讯作者：
Chauhan, SS
中科院分区：
文献类型：
--
作者：
Arora, S;Chauhan, SS
人组织蛋白酶L（hCATL）参与多种生理和病理过程。迄今为止，已知它由四种mRNA种类编码，即hCATL A、AI。AII和hCATL B，其5'非翻译区UTR不同）。其中，hCATL A. At和All是由同一初级转录物的选择性剪接产生的。hCATL A Ⅰ和hCATL A Ⅱ在hCATL A的外显子Ⅰ的3'端分别缺失27和90个碱基。本研究鉴定了一个新的剪接变体hCATL A Ⅲ，它同样缺失145个碱基。它是通过剪接hCATL A的第一外显子的136-280个碱基以及内含子I产生的，它们一起作为hCATL AIII的内含子。观察到HCATL AIII是五种不同人类细胞系中最丰富的剪接变体。体外转录偶联翻译研究显示，hCATL AIII的翻译效率分别是hCATL A、AI和AII的4.4倍、3.9倍和1.6倍。这些结果通过测量体外翻译产物的酶活性进一步证实。将hCATL AIII UTR克隆到荧光素酶报告基因上游导致报告基因的表达比含有hCATL A UTR的荧光素酶构建体高3.75倍。因此，我们已经确定了一种新的人类组织蛋白酶L剪接变异体。hCATL AIII.其在人类细胞系中最丰富并且以最高的效率被翻译。我们的结果证明了在hCATL AIII的UTR中存在或不存在足以赋予异源mRNA翻译优势的顺式作用调节因子。这种最有效翻译的剪接变体在恶性细胞中的优势表明它在癌症中人组织蛋白酶L的过表达中起关键作用。(C)2002 Elsevier Science B. V.保留所有权利。
Human cathepsin L (hCATL) has been implicated in a variety of physiological and pathological processes. It was hitherto known to be encoded by four mRNA species, namely hCATL A, AI. AII and hCATL B, differing in their 5' untranslated regions UTRs). Of these, hCATL A. At and All are produced by the alternative splicing of the same primary transcript. HCATL AI and hCATL AII, lack 27 and 90 bases, respectively, from the 3' end of exon I of hCATL A, The present study describes the identification of a new splice variant hCATL AIII, which similarly lacks 145 bases from the 3'end of exon I of hCATL A. It is produced by the splicing out of 136-280 bases of the first exon in addition to intron I of hCATL A, which together serve as an intron for hCATL AIII. HCATL AIII was observed to be the most abundant splice variant in five different human cell lines. In vitro transcription coupled translation studies revealed that hCATL AIII is translated with 4.4-, 3.9- and 1.6-fold higher efficiency as compared to hCATL A, AI and AII respectively. These results were further confirmed by measuring the enzymatic activities of the in vitro translated products. Cloning of hCATL AIII UTR upstream to luciferase reporter gene resulted in a 3.75-fold higher expression of the reporter gene as compared to the luciferase construct containing UTR of hCATL A. Thus, we have identified a novel human cathepsin L splice variant. hCATL AIII. which is most abundant in human cell lines and is translated with highest efficiency. Our results demonstrate either the presence of a positive or absence of a negative cis-acting regulatory clement(s) in the UTR of hCATL AIII that is sufficient to confer translational advantage to a heterologous mRNA. The predominance of this most efficiently translated splice variant in malignant cells suggests that it plays a key role in the over-expression of human cathepsin L in cancer. (C) 2002 Elsevier Science B.V. All rights reserved.