Open AccessA Deletion Mutation within the Ligand Binding Domain Is Responsible for Activation of Epidermal Growth Factor Receptor Gene in Human Brain Tumors
Author(s) -
Yamazaki Hitoshi,
Ohba Yoshito,
Tamaoki Norikazu,
Shibuya Masabumi
Publication year - 1990
Publication title -
japanese journal of cancer research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.035
H-Index - 141
eISSN - 1349-7006
pISSN - 0910-5050
DOI - 10.1111/j.1349-7006.1990.tb02644.x
Subject(s) - biology , complementary dna , epidermal growth factor , microbiology and biotechnology , mutation , receptor , intron , tyrosine kinase , receptor tyrosine kinase , epidermal growth factor receptor , gene , genetics
Two transplantable cell lines of human glioblastoma multiforme GL‐3 and GL‐5 carried an amplification and overexpression of structurally altered epidermal growth factor (EGF) receptor gene: the 140 kilodalton EGF receptors in these cases exhibited a constitutively expressed tyrosine kinase activity without the ligand. Here, we isolated the abnormal EGF receptor cDNA from GL‐5 cell line, and demonstrated that this cDNA bears a single large intramolecular deletion mutation 801 base pairs long within the ligand binding domain of EGF receptor. In other regions no amino acid substitution was observed. At the level of genomic DNA, this deletion appeared to start from the 1st intron and terminate in the 6th intron of the EGF receptor gene. However, in the two lines of glioblastoma, GL‐3 and GL‐5, the positions of the start or the end of the deletion mutation in these introns were not identical, suggesting an involvement of a unique recombination mechanism in the formation of deletion mutation. A weak but ligand‐independent transforming activity was observed in the deletion‐carrying EGF receptor cDNA.