Telomerase reverse transcriptase (TERT) is the protein component of telomerase and combined with an RNA molecule, telomerase RNA component, forms the telomerase enzyme responsible for telomere elongation. Telomerase is essential for maintaining telomere length from replicative attrition and thus contributes to the preservation of genome integrity. Although diverse mouse models have been developed and studied to prove the physiological roles of telomerase as a telomere-elongating enzyme, recent studies have revealed non-canonical TERT activities beyond telomeres. To gain insights into the physiological impact of extra-telomeric roles, this review revisits the strategies and phenotypes of telomerase mouse models in terms of the extra-telomeric functions of telomerase.
Animals ; Mice ; Mice, Knockout ; Telomerase/genetics/*metabolism ; Telomere/metabolism

OBJECTIVETo study the frequency of telomerase gene (TERC and TERT) mutation in Northern Chinese patients with acquired bone marrow failure syndromes (BMFS).

METHODSDNA extracted from blood samples of 90 patients with BMFS (including AA, MDS, and PNH) and 45 normal controls from 4 northern hospitals was collected. TERC and TERT mutation analysis was performed by PCR.

RESULTSTwo TERC mutations (n37 A-->G, and n66 G-->C) and two TERT mutations \[n1870 G-->T (E/*)\]; and \[n1780 G-->T (S/I)\] were identified in 90 BMFS patients. Among them, 3 mutations were reported for the first time. One patient with TERT mutation, however, was finally diagnosed as DKC instead of acquired AA, making the incidence of telomerase gene mutation in northern Chinese people with acquired BMFS 3.4%, similar to that of the western country people.

CONCLUSIONThe incidence of telomerase gene mutation in northern Chinese people with acquired bone marrow failure syndromes is 3.4%, similar to that of the western country people.

DNA Mutational Analysis ; Humans ; Mutation ; RNA ; genetics ; Syndrome ; Telomerase ; metabolism

To detect the expression of telomerase subunits (human telomerase reverse transcriptase, human telomerase associated protein 1 and human telomerase RNA) in gastric cancer and to examine the role that different telomerase subunits play in the gastric carcinogenesis, reverse transcription-polymerase chain reaction (RT-PCR) was used to detect telomerase subunits messenger RNA in 24 samples of gastric cancer and corresponding non-cancerous tissue. The results showed that the positive rate of hTERT mRNA from gastric cancer and corresponding non-cancerous tissues was 100% and 25%, respectively. The former was significantly higher than the latter (chi2 = 26.4, P < 0.01). The positive rate of hTEP1 mRNA from gastric cancer and corresponding non-cancerous tissues was 100% and 91.7%, respectively and no significant difference was found between them (chi2 = 2.1, P > 0.05). The positive rates of hTR for gastric cancer and corresponding non-cancerous tissues were both 100% and no significant difference existed between them. It is concluded that in contrast to hTEP1 and hTR, the up-regulation of hTERT mRNA expression may play a more important role in the development of gastric cancer.
Carrier Proteins/biosynthesis ; Carrier Proteins/genetics ; RNA/biosynthesis ; RNA/genetics ; RNA, Messenger/biosynthesis ; RNA, Messenger/genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Stomach Neoplasms/*metabolism ; Telomerase/*biosynthesis ; Telomerase/genetics

Total cDNA of human telomerase RNA(hTR) gene was cloned by means of RT-PCR and inverted into retroviral vector (pLNCX) to construct the mammalian cell expression plasmid. Then, by using lipofectin-mediated DNA transfection, the obtained expression plasmid was successfully transfected into human normal peripheral blood leukocyte. All data suggested that expression of transfected exogenous hTR gene can not reconstitute telomerase activity. Flow cytometry analysis and data from cell growth curve also indicated that expression of exogenous gene can not prolong the longevity of leukocyte, but rather inhibit the growth of leukocyte and induce its apoptosis. We conclude that expression of exogenous gene may block the coalition of telomerase RNA and its catalytic subunit(hTRT) and block the coalition of telomerase RNA template and telomere DNA, thus affecting telomerase activity and repressing cell proliferation.
Cells, Cultured ; Gene Expression ; Humans ; Leukocytes ; cytology ; enzymology ; metabolism ; RNA ; biosynthesis ; genetics ; Telomerase ; biosynthesis ; genetics ; Transfection

Bone Marrow Cells ; metabolism ; DNA-Activated Protein Kinase ; genetics ; metabolism ; Humans ; Leukemia ; genetics ; Nuclear Proteins ; genetics ; metabolism ; PTEN Phosphohydrolase ; genetics ; metabolism ; RNA, Messenger ; Telomerase ; genetics ; metabolism

The study was supposed to investigate the inhibitory effect of antisense phosphorothioate oligodeoxynucleotide (ASPSODN) targeting hTERT mRNA on gene of interest in K562 cells and influence of ASPSODN on telomerase activity and apoptosis of K562 cells. Human leukemia cell line K562 was transfected by liposome with ASPSODN and SPSODN (sense phosphorothioate oligodeoxynucleotide) at different concentrations (0.2, 0.6, 1.0 micromol/L). At the same time, blank control, liposome control and SPSODN groups were designed for comparison. The transfected cells were collected and detected at 24 and 48 hours; the expression of target gene hTERT mRNA and telomerase activity were detected by RT-PCR and TRAP-ELISA respectively, and cell apoptosis was assayed by flow cytometry. The results showed that after K562 cells were transfected for 24 hours, the expression of hTERT mRNA had no difference between liposome control (0.80+/-0.24), 0.2 micromol/L ASPSODN (0.69+/-0.12), 0.2 micromol/L SPSODN (0.72+/-0.25) and blank control (0.85+/-0.28), but the expression of hTERT mRNA in 0.6 micromol/L ASPSODN group (0.42+/-0.16) remarkably decreased as compared with liposome control group, 0.6 micromol/L SPSODN (0.69 +/- 0.26) had no obvious effect on the expression of hTERT mRNA, the expression of hTERT mRNA in 1.0 micromol/L ASPSODN and SPSODN groups both decreased; mortality of K562 cells transfected by liposome with 1.0 micromol/L ASPSODN and SPSODN remarkably increased. After 24 hours, telomerase relative activity of K562 cells showed no significant difference between blank control (88.9%) and liposome control (77.7%). The telomerase relative activities of K562 cells treated with 0.2, 0.6, 1.0 micromol/L ASPSODN were 60.6%, 52%, 58.2% respectively. There was significant difference as compared with blank control; 0.6 micromol/L ASPSODN showed significant difference (p=0.037), as compared with liposome control group. The telomerase relative activities in K562 cells treated with 0.2, 0.6, 1.0 micromol/L SPSODN were 76.1%, 72.2%, 65.7% respectively, but the telomerase relative activities of K562 cells in 0.2, 0.6 micromol/L SPSODN groups was not inhibited obviously. When K562 cells were treated for 48 hours, telomerase relative activity of K562 cells in each ASPSODN groups restored. It showed that telomerase relative activities of K562 cells treated with 0.2, 0.6, 1.0 micromol/L ASPSODN were 84.1%, 82.3%, 79.6% respectively, while telomerase relative activities of K562 cells treated with 0.2, 0.6, 1.0 micromol/L SPSODN for 48 hours were 74.8%, 74.5%, 67.9% respectively. Telomerase activity of K562 cells could not be inhibited by 0.2 and 0.6 micromol/L SPSODN. After culturing for 48 hours, the cell apoptosis rates of K562 in 0.6 micromol/L ASPSODN, 0.6 micromol/L SPSODN, liposome control and blank control groups were (4.82+/-0.39)%, (1.83+/-0.34)%, 1.84+/-1.04)%, (1.07+/-0.74)% respectively. There was difference between ASPSODN and SPSODN groups (p<0.05), but the significant difference was found in ASPSODN group as compared with liposome control and blank control (p<0.01). It is concluded that the ASPSODN targeting hTERT can specifically inhibit the expression of hTERT mRNA in K562 cells and significantly suppress the telomerase activity of K562 cells at 0.6 micromol/L, which inhibitory time is short. The ASPSODN at high concentration (1.0 micromol/L) shows definite cytotoxicity. 0.6 micromol/L of ASPSODN significantly induces cell apoptosis, while no such effect was seen in SPSODN group.
Apoptosis ; drug effects ; Humans ; K562 Cells ; Oligonucleotides, Antisense ; pharmacology ; Telomerase ; genetics ; metabolism

OBJECTIVESTo study the expression and the significance of telomerase gene hTERT in testes of infertile male.

METHODSBy using in situ hybridization(ISH) techniques, the expression of telomerase gene hTERT mRNA in testes of 47 infertile male and 10 normal testicular tissues were observed.

RESULTSIn male testes, there was a positive correlation between the expression of hTERT and the quantity and density of germ cells(spermatogonia, spermatocyte, spermatid). The expression of hTERT in some germinal cell of maturation arrest patients were not significantly different with those of normal.

CONCLUSIONSOur results suggest that the deficiency of telomerase might be a factor for germinal cell maturation arrest and there might be some other etiological factors in these patients. Our study provides experimental groundwork for the gene therapy of male infertility.

Humans ; Infertility, Male ; enzymology ; Male ; Spermatids ; Spermatocytes ; Spermatogenesis ; Spermatogonia ; Telomerase ; deficiency ; genetics ; metabolism ; Testis ; enzymology ; physiology

OBJECTIVETo investigate the expression of human telomerase reverse transcriptase (hTERT) in renal cell carcinoma (RCC) and its clinical significance.

METHODSThe expression levels of hTERT mRNA and protein were detected using RT-RCR and Western blotting in 45 RCC tissues, 45 adjacent tissues and 786-0 cell line, and the associations of hTERT expression with the tumor size, clinical stage, pathological type and grade were evaluated.

RESULTShTERT mRNA and protein was expressed at significantly higher levels in RCC tissues than in the adjacent tissues (P=0.000), and no correlation of hTERT expression was found with the tumor size, clinical stage, pathological type or grade.

CONCLUSIONhTERT might serve as a diagnostic and prognostic marker for RCC, and also shed light on the new clues for gene therapy of RCC.

Adult ; Aged ; Biomarkers, Tumor ; genetics ; metabolism ; Carcinoma, Renal Cell ; genetics ; metabolism ; pathology ; Female ; Humans ; Male ; Middle Aged ; RNA, Messenger ; genetics ; metabolism ; Telomerase ; genetics ; metabolism

Adenocarcinoma, Follicular ; genetics ; metabolism ; pathology ; Biomarkers, Tumor ; genetics ; Diagnosis, Differential ; Humans ; Matrix Metalloproteinase 1 ; biosynthesis ; genetics ; Telomerase ; biosynthesis ; genetics ; Thyroid Neoplasms ; genetics ; metabolism ; pathology ; ras Proteins ; biosynthesis ; genetics

OBJECTIVETo study hTERT mRNA expression in ameloblastoma (AB) and odontogenic keratocyst (OKC) and to investigate genesis, development and biological characteristics of AB and OKC.

METHODShTERT mRNA expression in 54 cases of AB, 16 cases of OKC, 7 cases of oral normal mucosa was detected by in situ hybridization.

RESULTSThe positive rates of hTERT mRNA in AB, OKC, and oral normal mucosa were 94.4% (51/54), 87.5% (14/16), 1/7, respectively. There was significant statistical difference (P < 0.001). About clinicalpathology of AB, there was no difference for hTERT expression (P > 0.05) hTERT mRNA was positive in peripheral and stellate reticula cells.

CONCLUSIONS(1) hTERT activity plays an important role in genesis, development of AB. (2) hTERT positive rate is related to cell differentiation and clinical biological behavior.

Ameloblastoma ; DNA-Binding Proteins ; metabolism ; Humans ; Jaw Neoplasms ; Odontogenic Cysts ; Odontogenic Tumors ; metabolism ; RNA, Messenger ; metabolism ; Telomerase ; genetics