Aim:To construct pEGFP-N3 recombinant vectors carrying adrenomedullin(AM)or fragments of the AM gene,and to express AM or fragments of AM from thepEGFP-N3 recombinant vectors(pEGFP-N3-AM 1-2 and pEGFP-N3-AM1-3)andstudy their biological properties on cultured rat renal mesangial cells(RMC).Methods:Total RNA of rat kidney was obtained using TriZol reagent.The cDNAwas synthesized by reverse transcriptase using oligo-deoxythymidine as primer.The fragments of AM gene were then amplified by polymerase chain reaction(PCR)with specific upstream and downstream oligonucleotides.The PCR prod-ucts were digested with EcoRI and BamHI and subcloned into the plasmid pEGFP-N3.Facilitated by cationic liposomes,RMC were transfected with pEGFP-N3-AM1-2 or pEGFP-N3-AM 1-3.After 24 h,green fluorescent protein(GFP)fluores-cent images were examined with a fluorescence microscope.After 48 h,the prolif-eration of RMC was detected using the MTT assay,and the mRNA expression oftransforming growthfactor-β1(TGF-β1)was measured by semiquantitative PCR.Results:DNA sequence reports verified that pEGFP-N3-AM1-2,which carriedthe full length AM gene translation fragment(preproadrenomedullin preproAM_(1-185)),and pEGFP-N3-AM1-3,which carried the translation fragment of preproAM[without adrenotensin(ADT,preproAM_(150-185))],were constructed successfully.After 24 h,green fluorescence was observed in RMC into which either pEGFP-N3-AM 1-2 or pEGFP-N3-AM 1-3 was transfected,while in the control cells no fluores-cence was observed.Either pEGFP-N3-AM1-2 or pEGFP-N3-AM1-3 delivery in-hibited the proliferation of RMC(P<0.01)and decreased the mRNA transcriptionlevel of TGF-~I in RMC(P<0.05).However,no significant difference was ob-served between the effects of pEGFP-N3-AM1-2 and pEGFP-N3-AM1-3.Conclusion:pEGFP-N3-AM 1-2 and pEGFP-N3-AM 1-3 were constructed suc-cessfully and were functionally expressed in RMC.Expressing the fragment ofAM without ADT has similar inhibitory biological effects on RMS proliferationand TGF-β1 transcription with full length preproAM. Aim: To construct pEGFP-N3 recombinant vectors carrying adrenomedullin (AM) or fragments of the AM gene, and to express AM or fragments of AM from the pEGFP-N3 recombinant vectors (pEGFP-N3- AM 1-2 and pEGFP- N3- AM1 -3) and study their biological properties on cultured rat renal mesangial cells (RMC). Methods: Total RNA of rat kidney was obtained using TriZol reagent. The cDNA was synthesized by reverse transcriptase using oligo-deoxythymidine as primer. The fragments of AM gene were amplified by polymerase chain reaction (PCR) with specific upstream and downstream oligonucleotides. The PCR prod-ucts were digested with EcoRI and BamHI and subcloned into the plasmid pEGFP-N3.Facilitated by cationic liposomes, RMC were transfected with pEGFP-N3-AM1- 2 or pEGFP-N3-AM 1-3. After 24 h, green fluorescent protein (GFP) fluores-cent images were examined with a fluorescence microscope. After 48 h, the prolif-eration of RMC was detected using the MTT assay, and the mRNA expression of transforming growth factor-β1 (TGF-β 1) was measured by semiquantitative PCR. Results: DNA sequence reports verified that pEGFP-N3-AM1-2, which carried the full length AM gene translation fragment, and pEGFP-N3- AM1-3, which carried the translation fragment of preproAM [without adrenotensin (ADT, preproAM_ (150-185))], were constructed successfully. After 24 h, green fluorescence was observed in RMC into either either pEGFP-N3- AM 1-2 or pEGFP- N3-AM 1-3 was transfected while in the control cells no fluorescene was observed. Either pEGFP-N3-AM1-2 or pEGFP-N3-AM1-3 delivery in-hibited the proliferation of RMC (P <0.01) and decreased the mRNA transcription level of TGF- ~ I in RMC (P <0.05) .However, no significant difference was ob-served between the effects of pEGFP-N3-AM1-2 and pEGFP-N3-AM1-3.Conclusion: pEGFP -N3-AM 1-2 and pEGFP-N3-AM 1-3 were constructed suc-cessfully and were functionally expressed in RMC. Expressing the fragment of AM without ADT has similar inhibitory biological effects on RMS proliferation and TGF-β1 transcription with full length preproAM.