We have previously shown that the tandemly duplicated 27 kDa maize sto
rage protein locus underwent mitotic rearrangement to yield a single-c
opy allele in isolates of the inbred line A188. This rearrangement con
tains a new LTR retrotransposon, designated Zeon-1. This middle repeti
tive element of 7313 bp had two long terminal repeats, a primer bindin
g site, a polypurine tract and a gag-related open reading frame of 375
amino acids. Transcripts of the gag-related region were detected by t
he polymerase chain reaction (PCR) in certain maize tissues, and Weste
rn blots detected the gag-related protein in the same tissues. Moreove
r, the product of this mitotic rearrangement was shown to contain the
same insertion site and 3' LTR as Zeon-1, suggesting that this rearran
gement occurs with unusual precision. Zeon elements were found to be p
resent in teosinte and not present in the Gramineae wheat, barley, sor
ghum and rye.