Abstract: BACKGROUND ＆ AIM： To clone the cDNA of both wide and mutant type of the human tumor suppressor gene PTEN and construct its expression vector respectively; investigate the effects of PTEN on cell growth in human brain glioma U251 cells. MATERIAL AND METHODS:Two DNA fragments were amplified from human placenta tissues and cancer of colon tissues by using RT-PCR and were cloned into pMD 18-T vector. After sequencing, the fragments were linked with expression vector pcDNA3.1(＋) vector. The two vector were transfected into U251. RESULTS: Human wild type and mutant type PTEN cDNA had been cloned and its expression vector had been constructed successfully. The progress of cell cycle was obviously arrested in the U251 transfected with wild PTEN gene, but was not the thing with nutant PTEN gene. CONCLUSION:PTEN may suppress tumor cells growth,the result makes the base for further study on the tumor suppression fumction of PTEN.

Key words: gene clone, tumor suppression gene PTEN, gene suppressor tumor, expression vector