Transpositional behavior of the maize En/Spm element in transgenic tobacco

Abstract
The transposable element Enhancer (En/Spm) of Zea mays encodes the functions necessary for transposition of members of the En‐I family of elements. En constructs were introduced into tobacco and transposition was demonstrated by cloning and DNA sequence analysis. Transcriptional analysis of En transgenic plants revealed 2.5 and 6 kb En homologous transcripts similar in size to those found in maize, in addition to aberrant splice products. Progeny analysis of a primary transformant indicates En transpositional activity after meiosis. In these progeny somatic variegation, at the NPT II gene, was demonstrated to be caused by En excision. Two re‐insertions of En were analyzed and found to reside in unique copy DNA while another was found in middle repetitive DNA.