OBJECTIVEo clone angiotensin-converting enzyme 2(ACE2) gene, to analyze its amino acids and nucleotides sequence and to investigate tissue distribution of ACE2 in adult mice.

METHODSThe full-length ACE2 encoding sequence was amplified from the RNA of mice kidney tissue by RT-PCR technique, cloned into plasmid pGEM-T easy, then subcloned into plasmid pcDNA3.1+. After identification of DNA sequence, the recombinant plasmid pmACE2 was transfected into Cos7 cells with lipofectin reagent. The transient expression of ACE2 molecule was detected by SDS-PAGE. Sequence analysis was conducted with CLUSTALX program. Tissue distribution of ACE2 in mice was detected by RT-PCR.

RESULTSA fragment about 2.6 kb was amplified and the recombinant plasmid pmACE2 was confirmed by two-enzyme digesting and DNA sequencing. The cloned DNA sequence was consistent with that previously reported, except for 3 variations: A701G, T1102C and T1330C. SDS-PAGE proved that expression of a soluble, truncated products form of ACE2 was a glycoprotein of approximately 80 kD in Cos7 cells. The predicted mice ACE2 sequence contained an N-terminal signal sequence (amino acid residues 1-18), a single HHEMGHIQ zinc-binding domain (amino acid residues 373-380) and C-terminal membrane anchor (amino acid residues 738-765). Mice ACE2 showed 84 % identity with that of human, and 90 % identity with that of rat. Expression of ACE2 was the greatest in lungs, hearts and kidneys, and moderate levels were also detected in testes and livers.

CONCLUSIONMice ACE2 gene has been cloned and successfully expressed in vitro. The tissue-specific expression of ACE2 in different species is not identical.