hTERT Can Function with Rabbit Telomerase RNA: Regulation of Gene Expression and Attenuation of Apoptosis

Department of Molecular Biology, School of Osteopathic Medicine, Stratford, New Jersey, 08084, USA.
Biochemical and Biophysical Research Communications (Impact Factor: 2.3). 12/2000; 278(3):503-10. DOI: 10.1006/bbrc.2000.3834
Source: PubMed


Telomerase is a specialized DNA polymerase that adds telomeric sequences onto chromosome ends. The functional telomerase complex contains a telomerase reverse transcriptase (TERT) and also a telomerase RNA (TR). Although it is well established that the human telomerase reverse transcriptase (hTERT) can function well in different human cell lines, it has not been shown whether it is compatible with telomerase template RNA from other species. Here we report that the expressed hTERT is functionally compatible with rabbit telomerase template RNA (rTR) as demonstrated by TRAP assay. The direct interaction between hTERT and rTR is further confirmed by immunoprecipitation-linked RT-PCR in which rTR is detected from the complex immunoprecipitated by an anti-hTERT antibody. The hTERT expressed in rabbit lens epithelial cells demonstrates two major functions: modulation of expression of other genes and attenuation of apoptosis. Thus, telomerase has a variety of functions besides telomere synthesis, and the template RNA is functionally conserved between human and rabbit.

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Available from: Yingwei Mao, Sep 10, 2014
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    • "Several groups successfully obtained an undefined extension of the lifespan of different cell types by exogenous expression of a TERT gene. In particular, the ectopic expression of human TERT (hTERT) allowed the immortalization of many human cell lines (Harley 2002; Belgiovine et al. 2008), as well as of cells from other species, including rabbit and bovine lens epithelial cells (Xiang et al. 2000; Wang et al. 2005), bovine microvascular endothelial cells (Buser et al. 2006), sheep fibroblasts (Cui et al. 2003), canine cell lines (Techangamsuwan et al. 2009), mesenchymal stem cells from rhesus monkey (Gao et al. 2008), and various types of porcine cells (Oh et al. 2007). Although several studies showed that TERT-immortalized cells maintain a normal phenotype, others demonstrated that immortalization could be associated with the appearance of cancerassociated changes and neoplastic transformation (Wang et al. 2000; Harley 2002; Mondello et al. 2003; Serakinci et al. 2004; Zongaro et al. 2005; Belgiovine et al. 2008). "
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    ABSTRACT: Many human primary somatic cells can be immortalized by inducing telomerase activity through the exogenous expression of the human telomerase catalytic subunit (hTERT). This approach has been extended to the immortalization of cell lines from several mammals. Here, we show that hTERT expression is not sufficient to immortalize primary fibroblasts from three equid species, namely donkey, Burchelli's zebra and Grevy's zebra. In vitro analysis of a reconstituted telomerase composed by hTERT and an equid RNA component of telomerase (TERC) revealed a low activity of this enzyme compared to human telomerase, suggesting a low compatibility of equid and human telomerase subunits. This conclusion was also strengthened by comparison of human and equid TERC sequences, which revealed nucleotide differences in key regions for TERC and TERT interaction. We then succeeded in immortalizing equid fibroblasts by expressing hTERT and hTERC concomitantly. Expression of both human telomerase subunits led to telomerase activity and telomere elongation, indicating that human telomerase is compatible with the other equid telomerase subunits and proteins involved in telomere metabolism. The immortalization procedure described herein could be extended to primary cells from other mammals. The availability of immortal cells from endangered species could be particularly useful for obtaining new information on the organization and function of their genomes, which is relevant for their preservation.
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    • "The retina, lens capsule/epithelial cells, lens fiber cells, and cornea were removed immediately and transferred into Eppendorf tubes containing 500 µl RNA extraction buffer (Trizol, BRL CAT# 15596–026; Gibco, Gaithersburg, MD) and were homogenized on ice with an Eppendorf tube micropestle (Brinkmann Instruments Inc., Westbury, NY). The remaining procedures of RNA extraction were the same as previously described [18,19]. "
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    • "Telomerase has an important role in cancer and inhibition of telomerase activity is a potential target for cancer treatment [16]. Telomerase is expressed in lung cancer cells [17] and this prevents apoptosis [18]. Thus, inhibition of telomerase might be a useful approach in stimulating lung cancer cell death [19]. "
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