[Effects of overexpression of human pol-beta on cellular response to DNA damage].

Objective: To investigate the biological effects of overexpression of the human DNA polymerase (pol-beta) on cellular response to DNA damage.

Methods: The cell strain HLFbeta from the stable overexpression of the human pol-beta was contaminated with methyl methanesulfonate (MMS) for investigating the effects of the pol-beta on the cellular responses to DNA damage on the aspects such as the DNA damage, the cell cycle and the induced mutation rate.

Results: The cell HLFbeta from the stable overexpression of the human pol-beta was obtained through the screening.

[Genetic polymorphisms of nucleotide repair gene hMTH1 in southern Chinese Han population].

In order to study the genetic polymorphisms of nucleotide repair gene hMTH1 in southern Chinese Han population, the polymorphisms of the gene's promoter and its five exons among peripheral blood lymphocytes of 172 Chinese Han people were analyzed with polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and DNA sequencing. The sequences of the promoter and exon 1 of hMTH1 gene were conserved. A T to C polymorphism was detected at the 73th base in exon 2.

[Construction of eukaryotic expression vector of hMTH1 gene antisense RNA].

Objective: To construct pEGFP-C1-T vector, an eukaryotic expression plasmid of hMTH1 gene antisense RNA.

Methods: The conservative region of hMTH1 gene was amplified by RT-PCR after total RNA being extracted from human embryo lung fibroblast (HLF) and then cloned into pGEM-T vector. After the recombinant plasmid was certified by DNA sequencing, the conservative region of hMTH1 gene was inserted into pEGFP-C1 vector reversedly and pEGFP-C1-T vector was constructed.

[Effects of hydroquinone on DNA and nucleus damage in human embryo lung fibroblasts].

Objective: To study DNA and nucleus damage in human embryo lung fibroblast (HLF) exposed to hydroquinone (HQ) and its genotoxicity.

Methods: HLF were treated with HQ (0, 10, 20, 40, 80 micro mol/L, respectively) for 3 h and DNA damage was detected by comet assay. HLF was also treated with the same concentrations of HQ for 1 h and micronucleus test was performed after they were cultured for 24 h.