A wheat HMW glutenin subunit gene reveals a highly repeated structure

A wheat genomic library was screened with two synthetic oligonucleotides (24 and 25 bases in length) complementary to a partial cDNA clone encoding a glutenin gene [Thompson et al. (1983) Theor. Appl. Genet. 67, 87-96]. Glutenins are large molecular weight aggregated proteins of grain endosperm, and major determinants of bread making quality of wheat. Of the two clones obtained one was fully characterized. It contained the sequence of the high molecular weight subunit of glutenin. The amino acid sequence derived from the gene sequence reveals a mature protein (817 amino acids) with a highly repeated structure of two different motifs corresponding to the high glutamine (35.7%), glycine (20.1%) and proline (13.1%) content. The gene does not contain an intron, and possesses a typical eukaryotic promoter; the RNA initiation site is 25-30 bases downstream.