Molecular cloning of a cDNA coding for neurofibromatosis type 1 protein isoform lacking the domain related to ras GTPase-activating protein.

Neurofibromatosis type 1 (NF1) is an autosomal dominant neurocutaneous disorder, and a gene linked to NF1 was recently identified. Its gene product (NF1 protein) contains a domain functionally related to mammalian ras GTPase-activating protein (GAP). Here, we cloned a cDNA coding for NF1 protein isoform lacking the region related to GAP from a oligo(dT)-primed cDNA library of human placenta. This cDNA carries the insert of about 2.4 kb, coding for a protein of 551 amino acid residues, which shares the same aminoterminal 547 residues with authentic NF1 protein. We show that NF1 mRNAs of about 2.9, 11, and 13 kb are expressed in human tissues, and that the isolated cDNA may represent the 2.9-kb transcript.