Comparative studies of the nucleotide sequences of pea seed storage protein genes

Abstract

Nucleotide sequence data from several pea (Piswn sativum L.) seed storage protein genes was obtained. Of two legumin genes sequenced, one was shown to be a pseudogene, apparently once coding for a polypeptide belonging to the 'major' legumin class, whilst the other was shown to be a functional gene coding for a polypeptide of the 'minor' legumin class. Sequence data was also obtained for two vicilin genes. Complete sequencing of one revealed it to be truncated by sequence of unknown origin at its 3' end, whilst partial sequence for the other suggested the presence of a stop codon in the coding region. These findings implied that both vicilin genes are no longer functional. Additionally, various comparisons of nucleic acid and amino acid sequence data were made between these genes and also with other legume seed storage protein genes. Results showed these genes conform with the major structural features of eukaryotic genes, and also revealed the presence of potential tissue -specific regulatory elements in the 5' flanking regions of the genes. Dendrograms for legume 11S and 7S classes of globulin seed storage protein genes clearly supported the model theory of each class having arisen by successive duplications from a common ancestral gene.