Expression of full length or truncated epidermal growth factor precursor transforms NIH3T3 fibroblasts.

Epidermal growth factor (EGF) is derived from a large precursor (EGFP) of unusual structure. As EGFP remains unprocessed in certain tissues, it is of biological relevance to study its activity. Activation of the EGF receptor by EGF is involved in transformation of NIH3T3 fibroblasts. We isolated clones of NIH3T3 expressing full length, cytoplasmic region deleted or EGF-repeats deleted EGFP. All clones formed colonies in soft agarose and tumors in nude mice. Two clones expressing EGF-repeats deleted EGFP formed more and larger colonies. To conclude, EGFP is biologically active. Deletion of the 8 EGF repeats may enhance anchorage independent growth in NIH3T3.