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The G-rich Pu39 region of the P1 promoter of the oncogene BCL-2, an apoptosis regulator, can fold into multiple G-quadruplex (G4) structures. Bcl2-2345 and Bcl2-1245 are two major G4 species forming with high thermal stability and distinct topologies in the Pu39 region, but their folding/unfolding kinetics have not yet been investigated. Here, we used magnetic tweezers to measure the mechanical stability and the folding/unfolding kinetics of the Bcl2-2345 and Bcl2-1245 G4 structures. We report that the hybrid-stranded Bcl2-2345 G4 had a lower mechanical stability than the parallel-stranded Bcl2-1245 G4. We observed that the Bcl2-2345 G4 is a kinetically favored structure, whereas the Bcl2-1245 G4, with a slow unfolding rate, may function as a kinetic barrier for transcription. We also determined that in addition to the Bcl2-2345 and Bcl2-1245 G4s, other stable DNA secondary structures, such as a hybrid-stranded Bcl2-1234 G4, can also form in the Pu39 sequence. The characterization of the folding/unfolding kinetics of specific G4s reported here sheds light on the participation of G4s during gene transcription and provides information for designing G4-targeting small molecules that could modulate BCL-2 gene expression.

To investigate the B lymphocytes(CD20) and T-lymphocyte subsets (CD4, CD8) expression and clinical significance in chronic rhinosinusitis.Immunohistochemical technique was applied to detect the expression of the B lymphocytes (CD20), helper T lymphocytes (CD4) and the cytotoxic T lymphocyte (CD8) in 15 patients with chronic rhinosinusitis without nasal polyps group (CRSsNP). 12 patients of chronic nasal sinusitis with nasal polyp (CRSwNP), 7 cases of recurrent CRSwNP group and 13 patients with inferior turbinate mucosa in the control group. The Mann-Whitney U test was used to analyze CD)20, CD4 and CD8 between the experimental groups and the control group. One- Way ANOVA was used to compare the lymphocyte infiltration between the experiment groups.Patients with CRS had higher infiltration of the B lymphocytes (CD20) and T lymphocyte subsets (CD4, CD88) than the patients of the control group (P0.05). The expression of T lymphocyte subsets (CD4, CD8) in CRSwNP and recurrent CRSwNP groups was significantly higher than in CRSsNP (P0.05). The expression of CD4 in the recurrent CRSwNP group was obviously higher than that in CRSsNP and CRSwNP (P0.01).The B lymphocytes, helper T cells and cytotoxic T cells have the high expression in CRS groups, which involved with the formation of inflammation. Furthermore nasal polyps are closely related to T lymphocyte infiltration.