Cell penetrating peptides (CPPs) are a series of promising carriers for delivering exogenous DNA to living cells. Among them, the combination of the human immunodeficiency virus TAT protein (TAT) with the SV40 large T protein nuclear localization signal (NLS) to form NLS-TAT performs well. In the present study, we took advantage of this new carrier to deliver transforming growth factor-beta 3 (TGF3) genes. TGF3 was expressed by the pEGFP-N1 vector following transfection of rat precartilaginous stem cells (PSCs), which promoted hTGF3 protein self-expression. At 24, 48, 72, and 120h after transfection, the expression levels of hTGF3 were found to be elevated as compared with the control. The expression of hTGF3 was found to mediate the chondrogenic effect of PSCs. Thus, we determined the expression of the chondrogenesis-related genes type II collagen, Sox 9, and aggrecan in PSCs at 24, 48, 72, and 120h after transfection. We found that their transcription and translation was augmented, which indicated a trend of active chondrogenesis in the PSCs. Our results demonstrated that NLS-TAT had the ability to deliver exogenous DNA into rat PSCs and could be actively expressed. This process successfully promoted PSC chondrogenesis. Additionally, PSC, may represent a new type of stem cells, and thus show great potential in regenerative repair following cartilage injury. J. Cell. Biochem. 114: 2588-2594, 2013. (c) 2013 Wiley Periodicals, Inc.