Glia activating factor and its production

A recombinant DNA containing a polynucleotide coding for a glia activating factor (GAF), said GAF having the following characteristics:

• (i) Heparin affinity:
• said glia activating factor is eluted from a heparin-Sepharose column at a saline concentration of 0.4 to 0.9M;
• (ii) Activity stability:
• the activity of said glia activating factor is lost by heat treatment at 100.degree. C. for 5 minutes, and partially lost by treatment at pH 2 for 30 minutes;
• (iii) Antigenicity:
• said glia activating factor does not exhibit the any immunological cross reaction with platelet-derived growth factor (PDGF), acidic fibroblast growth factor (aFGF) or basic fibroblast growth factor (bFGF);
• and
• (iv) Biological activity:
• said glia activating factor displays growth promoting activity upon glial cells, fibroblasts and rat pheochromocytoma PC-12 cells;
• said glia activating factor having the following amino acid sequence or a fragment thereof possessing GAF biological activity;
• ##STR13## wherein:
• n is 0 (SEQ ID NO:2) or 1 (SEQ ID NO:3);
• X.sub.1 represents Ala Pro Leu Gly Glu Val Gly Asn Tyr Phe Gly Val Gln Asp Ala Val Pro Phe Gly Asn Val Pro Val Leu Pro Val Asp Ser Pro Val Leu Leu Ser Asp His Leu Gly Gln Ser Glu Ala Gly Gly Leu Pro Arg Gly Pro Ala Val Thr Asp or a fragment thereof;
• and X.sub.2 represents Lys Val Pro Glu Leu Tyr Lys Asp Ile Leu Ser Gln Ser or a fragment thereof.