Objective To investigate the H_ 2O_ 2-induced expression of human histone acetyltransferase-like protein (hALP), a telomerase regulation-associated gene, and its effects on the stress-triggered cellular senescence.Methods The induced expression of hALP was measured by semi-quantitative RT-PCR and immunofluorescent histochemistry after treatment of HeLa cells by H_ 2O_ 2.The effects of hALP expression on cellular responses to H_ 2O_ 2 were analyzed by MTT, flowcytometry, and SA-β-gal staining, respectively.Results hALP mRNA could be dose-dependently induced by treatments of 0.2-1.6 mmol/L H_ 2O_ 2, and the induction could be observed after 6 hours and kept for 36 hours in the presence of 0.4 mmol/L H_ 2O_ 2.Meanwhile, the immunofluorescent staining showed marked stronger nuclear intensity of hALP protein in H_ 2O_ 2-treated HeLa cells.In the treatment of H_ 2O_ 2, the ectopic expression of hALP enhanced continuous growth and overcame G_ 2/M arrest as well as decreased senescence-associated β-gal staining.On the contrary, the transfected clones with antisense or blank vector and original HeLa cells presented growth suppression, G_ 2/M delay and higher percentage of SA-β-gal activities in the presence of H_ 2 O_ 2.Conclusions The expression of hALP could be up-regulated by treatment of H_ 2O_ 2, and elevated expression could enhance cellular resistance to H_ 2O_ 2-induced cellular senescence.The data might be of references to elucidation of basic biological function of hALP gene and its associated telomerase activity.
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