Developmental biochemistry of cottonseed embryogenesis and germination XVIII cDNA and amino acid sequences of members of the storage protein families

Abstract

We have sequenced cDNA clones representing each of the three distinct groups of storage proteins of the cotton seed. Characteristics of their mRNAs and derived proteins are given. Dot matrix analysis of the nucleotide and amino acid sequences shows that 2 of these groups of proteins have a great deal of vestigial homology at low stringency and should be considered subfamilies of a single storage protein gene family. The remaining group is quite distinct and should be considered a separate multigene family. It also can be divived into 2 subfamilies based on the presence or absence of glycosyl residues and other sequence differences. These proteins are processed to smaller species during embryogenesis, and all of the mature storage proteins of cotton can be traced back to these 2 gene families. In view of these relationships we propose that these 2 families be called the α and β globulins of cotton storage proteins, each comprised of an A and B subfamily.