Isolation and characterization of a mouse cDNA clone that expresses mast-cell growth-factor activity in monkey cells

A cDNA sequence coding for mouse mast-cell growth-factor (MCGF) has been cloned from a cDNA library prepared from mRNA derived from a concanavalin A-activated mouse T-cell clone. Cloning was achieved using the pcD vector that permits expression of cDNA inserts in mammalian cells. The DNA sequence codes for a polypeptide of 166 amino acid residues including a putative signal peptide. The supernatant fluid obtained after transfection of COS-7 monkey cells with the pcD-MCGF plasmid had mouse MCGF activity. The MCGF amino acid sequence between amino acids 33 and 41, deduced from the nucleotide sequence of its cDNA, is identical to the NH2-terminal sequence of the mouse lymphokine, interleukin 3, suggesting that MCGF is related to interleukin 3.