Restriction digests of the clone give the following sizes (kb): EcoRI--4.1, 2.7; PvuII--4.0, 2.5, less than 0.5; HindIII--6.8; SalI--6.8; BamHI--3.6, 3.2. Restriction digests of the clone give the following sizes (kb): BglI--3.7, 1.3, 1.2, 0.78. The insert extends from the EcoRI site at nucleotide 1013 (amino acid 294) through the 3' untranslated region, including poly(A). This insert does not encode the cysteine-rich region which is part of the alpha subunit. The insert does encode a portion of the 3' end of the alpha subunit and all of the beta subunit including the transmembrane and tyrosine kinase domains. A 1.3 kb BglI fragment (12.1B1.3, 1601 - 2963) detects a 3-allele SstI RFLP not detected by the 1.6 kb PstI fragment (12.1P1.6, 2744 - 4343). The BglI fragment encodes the 3' region of the alpha chain and the 5' region of the beta chain. The 7.0/6.2 kb RsaI polymorphism has been detected with the 1.3 kb BglI fragment probe (12.1B1.3, 1601 - 2963). The polymorphic site maps between nucleotides 1928 and 2478 of the cDNA. The 2.4/2.2 kb RsaI polymorphism has been detected with the 1.3 kb BglI fragment (12.1B1.3, nt 1601-2963). The polymorphic site maps between nt 2744 and 2963 of the cDNA. In American Blacks, a 6.4 kb fragment is sometimes (0.6%) detected in RsaI digests. This probably results from another polymorphic RsaI site 0.6 kb from the 7.0 kb fragment. In Pima Indians, a 3.4 kb fragment is detected (34%) in RsaI digests using the 1.3 kb BglI probe. This probably represents another polymorphic site 3.4 kb from one end of both 6.2 and 7.0 kb fragments. The SacI site polymorphism (alleles 9.4 kb/7 + 2.4 kb) appears to be private to Caucasian populations (the 7 + 2.4 kb allele detected in only 1/48 Pima Indians and 1/48 American Blacks). The polymorphic BglII site has been detected using the intact insert or the 1.6 kb PstI fragment (12.1P1.6, 2744-4343). The polymorphic site maps between nucleotides 2744 and 2963 of the cDNA sequence. |
