The nucleotide sequence of mouse cDNA for spermidine synthase appeared
to contain 75 nucleotides of 5' untranslated region, an open reading
frame of 909 nucleotides and 297 nucleotides of 3' untranslated region
. The open reading frame encoded a polypeptide of 302 amino acids, dis
playing 95% similarity to human and 33% similarity to E. coli spermidi
ne synthase. The 3' flanking region contained an unusual polyadenylati
on signal AATACA.