A Preliminary Investigation On BRG1's Role In DNA Damage And Repair

The highly condensed chromatin prevents the binding of transcription factors and cofactors to DNA. Therefore, it's crucial to relief the repressive environment for transcription through chromatin remodeling activities. Recently, chromatin remodeling is carried out by at least two mechanisms: ATP-dependent chromatin remodeling complexes and histone modification complexes. The representive of the former one is the SWI/SNF comlex, the ATPase subunit of which is BRG1 or BRM in human. BRG1 plays an important role in the regulation of gene transcription, replication, recombination and etal. However, it`s still unclear that the function BRG1 carries out in DNA damage and repair.DNA is the basis of genetic material, which may give rise to some kinds of damage in the existence of physical and chemical factors. CPD and 6-4PP are the main photoproducts after UV irradiation. For this kind of damage, nucleutide excision repair (NER) is the major repair pathway.In this article, we mainly discussed the relationship between the BRG1 and DNA damage and repair. Firstly, we set up a UV-induced DNA damage and repair model through distinct dose of UV irradiation and tests to the cellular apoptosis by flow cytometry in order to find suitable UV dose. On the basis of this model, BRG1 expression plasmid and vector plasmid pBJ5 were transfected separately into SW13, which would repair themselves during the distinct repair time of 0h, 6h and 24h after 30J/m2 UV irradiation, then tests were carried out to justify the content of primary cellular apoptosis. The results showed that the percentage of primary cellular apoptosis of SW13 with transfection of BRG1 expression plasmid was lower obviously than that with transfection of vector plasmid pBJ5, especially after the repair time of 24h. All of these above indicated that BRG1 took part in and promoted DNA damage and repair. The results made foundation for the research of the role of BRG1 on DNA damage and repair, also provided clues for further exploring the specific mechanism of BRG1 on this field, and help us to understand generally about varies important roles the chromatin-remodeling complexes play in cells.