EXPRESSION OF ENDOTHELIN-2 (ET-2) GENE IN A HUMAN RENAL ADENOCARCINOMA CELL-LINE - PURIFICATION AND CDNA CLONING OF ET-2

It has been found that human renal adenocarcinoma ACHN cells synthesize and secrete immunoreactive endothelin (ir-ET) in the culture medium. Partial characterization of this material with reverse-phase high-performance liquid chromatography (RP-HPLC) suggested that ACHN cells synthesized only human endothelin-2 (ET-2). Isolation and characterization of this ir-ET-2 has revealed that this peptide has almost the same amino acid sequence and molecular weight as that of human ET-2 deduced from the nucleotide sequence of cloned human ET-2 gene. To delineate the precise structure of human ET-2 precursor, ET-2 cDNAs were cloned from a cDNA library constructed with mRNA derived from the ACHN cells, and the nucleotide and deduced amino acid sequences were determined. The ET-2 cDNA that has the longest open reading frame encodes prepro-ET-2 protein, consisting of 178 amino acid residues. The ET-like sequence found in the prepro-ET-1 and -ET-3 was also conserved in this prepro-ET-2. The Northern blot analysis of mRNA revealed that the transcript of the human ET-2 gene was 1.4 kb.