Sequence and characterization of 6 Lea proteins and their genes from cotton

Lea genes code for mRNAs and proteins that are late embryogenesis abundant in higher plant seed embryos. They appear to be ubiquitous in higher plants and may be induced to high levels of expression in other tissues and at other times of ontogeny by ABA and/or desiccation. Presented here are the genomic and cDNA sequences for 6 of these genes from cotton seed embryos and the derived amino acid sequences of the corresponding proteins.The Lea genes contain the standard sequence features of eucaryotic genes (TATA box and poly (A) addition sequences) and have 1 or more introns. Sequences differences between cDNA and genomic DNA confirm the existence of small multigene families for several Lea genes. The amino acid composition and sequence for the Lea proteins are unusual. Five are extremely hydrophilic, four contain no cys or trp and 4 have sequence domains that suggest amphiphilic helical structures. Hypothetical functions in desiccation survival, based on amino acid sequence, are discussed.