CDNA SEQUENCE-ANALYSIS OF THE HUMAN BRAIN INSULIN-RECEPTOR

Brain tissue mRNA was amplified using polymerase chain reaction (PCR) with eight overlapping sets of primers that span the cDNA coding seque nce for the human placental insulin receptor. Only the A isoform (Irki ng exon 11) of the receptor was detected. No difference was found in t he predicted amino acid sequence of brain derived insulin receptor cDN A compared with the receptor from human placenta. A silent polymorphis m was detected at nucleotide position 1698 (amino acid 523), confirmin g that mRNA corresponding to both alleles of the human brain receptor was sequenced. Our findings indicate that the unique glycosylation pro perties of brain insulin receptors do not stem from differences in pri mary structure, but rather are due to tissue-specific differences in p ost-translational processing. (C) 1995 Academic Press. Inc.