ABSTRACT
Objective To investigate the effects of silencing the gene of single-stranded DNA-binding protein 1 (SSB1) on proliferation and DNA repair of rat submandibular gland (SMG) cells after irradiation, and explore the relationship between SSB1 and DNA damage repair. Methods Primary rat SMG cells were obtained by mechanical-enzyme digestion and identified by immunohistochemistry. The cells were divided into three groups, including blank control, negative control and shRNA transfection group. The shRNA was transfected into cells by recombinant adenovirus vector. Real-time quantitative PCR ( qRT-PCR) was used to detect the expression of SSB1 after silencing. The cell viability was detected by CCK-8 assay. Immunofluorescence analysis was performed to observe the dynamic formation of γ-H2AX foci. Results The SMG cells were positively stained for both Pan CK and α-Amylase. The efficiency of shRNA transfection was about 90%at 72 h post-transfection. Compared with the blank control group, the expression of SSB1 was significantly decreased in the cells transfected with shRNA (t=16. 24, P<0. 05). The cell viability of shRNA transfection group without irradiation was decreased indistinctively and became lower than the blank control group significantly until 120 h(t=3. 29, P<0. 05). After radiation with 5 Gy of γ-rays, the cell viability of shRNA transfection group was lower than that of the control groups significantly (F=10. 19-30. 13, P<0. 05). Silencing the expression of SSB1 could increase the number ofγ-H2AX foci in SMG cells at different time of radiation. Conclusions After silencing of the expression of SSB1, the SMG cells could be more radiosensitive, which indicats that SSB1 may play an important role in DNA damage repair after radiation.
ABSTRACT
Objective To investigate the effects of silencing the gene of single-stranded DNA-binding protein 1 (SSB1) on proliferation and DNA repair of rat submandibular gland (SMG) cells after irradiation, and explore the relationship between SSB1 and DNA damage repair. Methods Primary rat SMG cells were obtained by mechanical-enzyme digestion and identified by immunohistochemistry. The cells were divided into three groups, including blank control, negative control and shRNA transfection group. The shRNA was transfected into cells by recombinant adenovirus vector. Real-time quantitative PCR ( qRT-PCR) was used to detect the expression of SSB1 after silencing. The cell viability was detected by CCK-8 assay. Immunofluorescence analysis was performed to observe the dynamic formation of γ-H2AX foci. Results The SMG cells were positively stained for both Pan CK and α-Amylase. The efficiency of shRNA transfection was about 90%at 72 h post-transfection. Compared with the blank control group, the expression of SSB1 was significantly decreased in the cells transfected with shRNA (t=16. 24, P<0. 05). The cell viability of shRNA transfection group without irradiation was decreased indistinctively and became lower than the blank control group significantly until 120 h(t=3. 29, P<0. 05). After radiation with 5 Gy of γ-rays, the cell viability of shRNA transfection group was lower than that of the control groups significantly (F=10. 19-30. 13, P<0. 05). Silencing the expression of SSB1 could increase the number ofγ-H2AX foci in SMG cells at different time of radiation. Conclusions After silencing of the expression of SSB1, the SMG cells could be more radiosensitive, which indicats that SSB1 may play an important role in DNA damage repair after radiation.
ABSTRACT
Although some mutations are beneficial and are the driving force behind evolution, it is important to maintain DNA integrity and stability because it contains genetic information. However, in the oxygen-rich environment we live in, the DNA molecule is under constant threat from endogenous or exogenous insults. DNA damage could trigger the DNA damage response (DDR), which involves DNA repair, the regulation of cell cycle checkpoints, and the induction of programmed cell death or senescence. Dysregulation of these physiological responses to DNA damage causes developmental defects, neurological defects, premature aging, infertility, immune system defects, and tumors in humans. Some human syndromes are characterized by unique neurological phenotypes including microcephaly, mental retardation, ataxia, neurodegeneration, and neuropathy, suggesting a direct link between genomic instability resulting from defective DDR and neuropathology. In this review, rare human genetic disorders related to abnormal DDR and damage repair with neural defects will be discussed.