Modulation effects of HIV-1 Tat on cyclinB1

OBJECTIVE To investigate the effects of HIV-1 Tat on the the cell cycle-related cyclinB1 protein.METHODS A human rhabdomyosarcoma cell lines TE671 and TT2 cells generated from TE671 cells by transfecting with tat gene of the HIV-1 strain were employed.The expressions of cyclinB1 protein when subjected to ionizing radiation anterior-posterior were detected by Western Blot assay,and the Northern-Blot and semiquantitative RT-PCR were employed to analyse the cyclinB1 protein expression on the level of mRNA.The cycloheximide blocking and co-immunoprecipitation assays were carried out to detect the stability of cyclinB1 protein.RESULTS The expression of cyclinB1 protein was significantly enhanced in TT2 cells by transfecting with tat gene of the HIV-1 strain when subjected to ionizing radiation and unionizing radiation.The cycloheximide blocking and co-immunoprecipitation assays demonstrated that the constitutive overexpression of cyclinB1 protein mainly generate to the protein modification after protein synthesis.CONCLUSION HIV-1 Tat is able to enhance the stability of cyclinB1 protein,and decrease the level of cyclinB1 protein polyubiquitinated.these observations may be help to change the process of tumor cell cycle,and then effect clinical therapy via interfering Tat expression by molecular biology method to regulation the expression of cyclinB1 protein.