title: Analysis of the nuclear localization signal of TRF1 in non-small cell lung cancer.
abstract: Several studies revealed a similar down-regulation of telomeric repeat binding factor 1 (TRF1) in tumors. We have previously reported the TRFl expression levels were down-regulation in non-small cell lung cancer (NSCLC). The regulation of TRFl localization is proposed to be important for the function and expression. The nuclear localization signal (NLS) and nuclear export signal (NES) are often important clues to localization of protein. The objective of the present study was to investigate the NLS and NES of TRFl in NSCLC patients. Thirty (30) patients with NSCLCs had undergone radical operations in The First Affiliated Hospital, College of Medicine, Zhejiang University. DNA sequences of NLSs and NESs were amplified by PCR. The PCR products were analyzed by DNA sequencing. There were four NLSs of the TRFl protein, including two monopartite and two bipartite NLSs. The NLSs sequences were included in 337KKERRVGTPQSTKKKKESRR356. The exon 8 and exon 9 of TRFl DNA were covered the NLS sequences. The sequences of predicted NESs were 11WMLDFLCLSL86 and 174NLLKLQALAV183, respectively. The exon 1, exon 3 and exon 4 of TRFl were covered the NES sequences. In NSCLCs, there was no a mutation, deletion, or substitution in NLS and NES of TRFl. We conclude that the NLS and NES sequences in NSCLCs patients did not have mutations. Down-expression of TRFl does not indicate gene mutation of NLS and NES in NSCLCs.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China. hjsl@mail.hz.zj.cn
authors.forename: Jian
authors.initials: J
authors.lastname: Hu
authors.forename: Li
authors.initials: L
authors.lastname: Sun
authors.forename: Lu-Ming
authors.initials: LM
authors.lastname: Wang
authors.forename: Su-Jun
authors.initials: SJ
authors.lastname: Jiang
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics*; D015536:Down-Regulation / Q000235:genetics*; D005091:Exons; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics*; D008297:Male; D049790:Nuclear Export Signals / Q000235:genetics; D019913:Nuclear Localization Signals / Q000235:genetics; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D000089804:Shelterin Complex; D034501:Telomere-Binding Proteins / Q000235:genetics*; D035321:Telomeric Repeat Binding Protein 1 / Q000235:genetics*
chemical_list: D049790:Nuclear Export Signals; D019913:Nuclear Localization Signals; D000089804:Shelterin Complex; C059329:TERF1 protein, human; D034501:Telomere-Binding Proteins; D035321:Telomeric Repeat Binding Protein 1