RESUMEN
Objective To establish a doxycycline-controlled immortalized pre-cartilaginons stem cells (IPCSCs) strains, clone parathroid hormone-related peptide[PTHrP(1-36)] gene and construct re- sponsive plasmid, pTRE-PTHrP (1-36). Methods Plasmid pTet-on was transfected into IPCSCs by using LipoinfectaminTM 2000 and then the stable clones were obtained by G418 screening. The doxycyc- line was added into the medium of monoclonal cells that were transiently transfected with plasmid pTRE- 2Hyg-Lue. The total RNA was extracted from PCSCs and the PTHrP(1-36) gene obtained by RT-PCR method. Then, the PTHrP (1-36) gene was subcloned to plasmids of Tet-responsive element with the se- lection marker of hygromycin pTRE-2Hyg to construct recombinant eukaryotic expression plasmid pTRE- PTHrP(1-36). After transferred into E. coli-DH5α, the clone was amplified, the recombinant plasm0ids were purified and identified by double-enzyme digestion. Results The doxycycline induced IPCSCs line was obtained, with 50 times higher than the non-induced cell line. Double enzyme digestion analysis and sequencing showed that the target gene was cloned into recombinant plasmid. Conclusions The induced IPCSCs line can be used to highly express alien genes. The responsive plasmid containing PTHrP (1-36) gene may be premising for rigorous control of PTHrp (1-36) gene expression.