Complete nucleotide sequence of a soybean actin gene

Abstract
Soybean contains a small multigene family of actin-related sequences. The complete nucleotide sequence of a soybean actin gene carried on the recombinant plasmid pSAc3 was determined. As deduced from the nucleotide sequence, this soybean actin is composed of 376 amino acids. Compared to other eukaryotic actins, pSAc3 actin has a deletion of 1 amino acid between residues 118 and 122. The initiator methionine is followed by alanine, which is not found at this position in other eukaryotic actins. pSAc3 actin differs, in primary sequence, more from fungal and animal actins than any of the known nonplant actins differ from each other. pSAc3 actin apparently is related to both cytoplasmic and muscle specific actins in the location of specific NH2-terminal amino acids. The coding sequence is interrupted by 3 small introns, each < 90 base pairs long. The splice junctions are similar to those found in other eukaryotic genes, suggesting the presence of a similar splicing apparatus in higher plants. Introns 1 and 3 interrupt the reading frame after codons 20 and 355, respectively. Intron 2 splits a glycine codon at position 151. None of these intron positions is conserved relative to the positions of introns in other actin genes examined.