AvrXa27 binding influences unwinding of the double-stranded DNA in the UPT box

Development of a Transcriptional Activator-Like Effector Protein to Accurately Discriminate Single Nucleotide Difference

Transcriptional activator-like effector (TALE), a DNA-binding protein, is widely used in genome editing. However, the recognition of the target sequence by the TALE is adversely affected by the number of mismatches. Therefore, the association constant of DNA-TALE complex formation can be controlled by appropriately introducing a mismatch into the TALE recognition sequence. This study aimed to construct a TALE that can distinguish a single nucleotide difference. Our results show that a single mismatch present in repeats 2 or 3 of TALE did not interfere with the complex formation with DNA, whereas continuous mismatches present in repeats 2 and 3 significantly reduced association with the target DNA. Based on these findings, we constructed a detection system of the one nucleotide difference in gene with high accuracy and constructed a TALE-nuclease (TALEN) that selectively cleaves DNA with a single mismatch.

Expression of miR-34a and Ki67 in nasopharyngeal carcinoma and the relationship with clinicopathological features and prognosis

Expression levels of miR-34a and Ki67 in nasopharyngeal carcinoma (NPC) and the relationship with clinicopathological features and prognosis were studied. A prospective study was performed on 56 cases of NPC tissues and 56 cases of adjacent tissues collected in Xiangyang No. 1 People's Hospital. The expression levels of miR-34a, Ki67 in NPC and adjacent tissues were detected by RT-qPCR. The association among the expression levels of miR-34a and Ki67, the clinicopathological features and prognosis of patients was analyzed. The relative expression levels of miR-34a in 56 cases of NPC were lower than those of the adjacent tissues. The expression of miR-34a in NPC was significantly associated with bone metastasis and TNM staging (P<0.001). The relative expression of Ki67 in 56 cases of NPC was higher than that of the adjacent tissues. The expression of Ki67 in NPC was significantly associated with lymphatic metastasis and TNM staging (P<0.001). The 5-year survival of patients with low expression of miR-34a was significantly lower than that of patients with high expression, and the survival of patients with high expression of Ki67 was significantly lower than that of patients with low expression. According to Pearson's correlation analysis, Ki67 expression was negatively correlated with miR-34a expression in NPC tissues. In conclusion, the expression of Ki67 in NPC was upregulated, while the expression of miR-34a in NPC was downregulated. miR-34a expression in NPC was significantly associated with bone metastasis and TNM staging, and Ki67 expression in NPC was significantly associated with lymphatic metastasis and TNM staging. In addition, there was a negative correlation between miR-34a and Ki67 expression levels, and the two can be used as predictors of NPC-associated mortality. The expression levels of miR-34a and Ki67, as well as TNM staging were associated with the prognosis of NPC patients.

Prognostic analysis of patients with locally advanced nasopharyngeal carcinoma following intensity modulated radiation therapy

The present study retrospectively analyzed the prognostic factors of 135 patients with locally advanced nasopharyngeal carcinoma (NPC) who received intensity modulated radiation therapy between August 2008 and January 2012 at Xiangya Hospital of Central South University. Patients were staged from III-IVA according to the 7th American Joint Committee on Cancer staging system. Using Statistical Analysis System 9.3 software, the present study demonstrated that, among these 135 patients, the 5-year overall survival, the 5-year local relapse-free survival, and the 5-year disease metastasis-free survival were 84, 82, and 78%, respectively. Multivariate Cox regression analysis identified that targeted treatment [hazard ratio (95% confidence interval), 2.642 (1.001, 6.972); P=0.0497] served as an independent negative prognostic factor in locally advanced NPC. The results of immunostaining revealed that the staining intensity of the radiation-resistant group was increased compared with that of the radiation-sensitive group. These results demonstrate that a high expression of EGFR may be associated with radiation resistance, and targeted treatment may not be effective in patients with locally advanced nasopharyngeal carcinoma with low expression of EGFR.